max / makeover

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1	//! Shared theme loading + intent resolution for TOML-based theme files.
2	//!
3	//! Used by GoingsOn, Balanced Breakfast (Tauri apps), audiofiles (egui), and the
4	//! MNW web server. Themes are authored by intent ("human design"): colors are
5	//! declared by role (surface / content / action / status / line / category), not
6	//! by hue. This crate is the single place that resolves an authored theme into a
7	//! full set of intent tokens — including the derived interactive states
8	//! (hover/active/selection/row-stripe/contrast) that each app used to recompute
9	//! itself — and emits them as CSS variables or RGB tuples.
10	//!
11	//! Theme file shape:
12	//! ```text
13	//! [meta]
14	//! name = "Nord"
15	//! variant = "dark" # or "light"
16	//!
17	//! [surface] # container backgrounds by role/elevation
18	//! page = "#2e3440"; raised = "#3b4252"; sunken = "#434c5e"; overlay = "#3b4252"
19	//!
20	//! [content] # the ink. Its emphasis steps are derived, not authored:
21	//! primary = "#d8dee9" # `content-secondary` and `content-muted` are tonal
22	//! # steps of this toward `surface.page`. See `Emphasis`.
23	//!
24	//! [action] # interactive / brand color
25	//! primary = "#81a1c1"
26	//!
27	//! [status] # state semantics
28	//! danger = "#bf616a"; success = "#a3be8c"; warning = "#ebcb8b"; info = "#88c0d0"
29	//!
30	//! [line]
31	//! border = "#4c566a"
32	//!
33	//! [category] # distinct decorative colors for tags/badges/charts
34	//! one = "#bf616a"; two = "#a3be8c"; three = "#81a1c1"
35	//! four = "#ebcb8b"; five = "#b48ead"; six = "#88c0d0"
36	//! ```
37
38	// Color-space math: single-letter channel names (r/g/b/l/m/s) and the published
39	// high-precision OKLab/sRGB matrix constants are the domain vocabulary here.
40	#![allow(clippy::many_single_char_names, clippy::unreadable_literal)]
41
42	use serde::Serialize;
43	use std::collections::{BTreeMap, HashMap};
44	use std::path::{Path, PathBuf};
45
46	/// The color sections an authored theme may declare.
47	pub const COLOR_SECTIONS: &[&str] = &["surface", "content", "action", "status", "line", "category"];
48
49	/// Theme metadata parsed from the `[meta]` section.
50	#[derive(Debug, Clone, Serialize)]
51	#[serde(rename_all = "camelCase")]
52	pub struct ThemeMeta {
53	pub id: String,
54	pub name: String,
55	pub variant: String,
56	pub is_custom: bool,
57	}
58
59	/// A loaded theme: metadata plus the authored colors, flattened to dotted keys
60	/// (e.g. `"surface.page"`, `"status.danger"`, `"category.one"`).
61	#[derive(Debug, Serialize)]
62	#[serde(rename_all = "camelCase")]
63	pub struct ThemeColors {
64	pub meta: ThemeMeta,
65	pub colors: HashMap<String, String>,
66	}
67
68	// ============================================================================
69	// Color math — perceptual (OKLab) derivations + WCAG contrast.
70	//
71	// Interactive states (hover/active/selection/surfaces) are derived in OKLab so
72	// equal steps look equal across every theme's hues (Ottosson 2020; the modern
73	// CIELAB). Text-on-color is picked by the WCAG 2.x contrast ratio, not a naive
74	// luminance threshold, so the choice actually meets AA where achievable.
75	// This is the single source of truth shared by every product.
76	// ============================================================================
77
78	/// An sRGB color. Hex round-trips losslessly.
79	#[derive(Clone, Copy, Debug, PartialEq, Eq)]
80	pub struct Rgb {
81	pub r: u8,
82	pub g: u8,
83	pub b: u8,
84	}
85
86	impl Rgb {
87	/// Parse `#rgb` or `#rrggbb` (case-insensitive). Returns `None` otherwise.
88	pub fn from_hex(s: &str) -> Option<Rgb> {
89	let h = s.strip_prefix('#')?;
90	let (r, g, b) = match h.len() {
91	6 => (
92	u8::from_str_radix(&h[0..2], 16).ok()?,
93	u8::from_str_radix(&h[2..4], 16).ok()?,
94	u8::from_str_radix(&h[4..6], 16).ok()?,
95	),
96	3 => {
97	let d = \|c: &str\| u8::from_str_radix(c, 16).ok().map(\|v\| v * 17);
98	(d(&h[0..1])?, d(&h[1..2])?, d(&h[2..3])?)
99	}
100	_ => return None,
101	};
102	Some(Rgb { r, g, b })
103	}
104
105	/// Lowercase `#rrggbb`.
106	pub fn to_hex(self) -> String {
107	format!("#{:02x}{:02x}{:02x}", self.r, self.g, self.b)
108	}
109
110	pub fn tuple(self) -> (u8, u8, u8) {
111	(self.r, self.g, self.b)
112	}
113	}
114
115	/// A color in OKLab (perceptually uniform): `l` lightness in [0,1], `a`/`b` opponent axes.
116	#[derive(Clone, Copy, Debug)]
117	pub struct Oklab {
118	pub l: f32,
119	pub a: f32,
120	pub b: f32,
121	}
122
123	fn srgb_to_linear(c: u8) -> f32 {
124	let c = c as f32 / 255.0;
125	if c <= 0.04045 {
126	c / 12.92
127	} else {
128	((c + 0.055) / 1.055).powf(2.4)
129	}
130	}
131
132	fn linear_to_srgb(c: f32) -> u8 {
133	let c = c.clamp(0.0, 1.0);
134	let v = if c <= 0.0031308 {
135	c * 12.92
136	} else {
137	1.055 * c.powf(1.0 / 2.4) - 0.055
138	};
139	(v * 255.0).round().clamp(0.0, 255.0) as u8
140	}
141
142	impl Rgb {
143	/// Convert to OKLab (Ottosson's sRGB matrices).
144	///
145	/// The matrix coefficients are quoted at their published precision so they
146	/// can be diffed against the reference. `f32` rounds them at compile time;
147	/// truncating the literals would only make them harder to check.
148	#[allow(clippy::excessive_precision)]
149	pub fn to_oklab(self) -> Oklab {
150	let (r, g, b) = (
151	srgb_to_linear(self.r),
152	srgb_to_linear(self.g),
153	srgb_to_linear(self.b),
154	);
155	let l = 0.4122214708 * r + 0.5363325363 * g + 0.0514459929 * b;
156	let m = 0.2119034982 * r + 0.6806995451 * g + 0.1073969566 * b;
157	let s = 0.0883024619 * r + 0.2817188376 * g + 0.6299787005 * b;
158	let (l_, m_, s_) = (l.cbrt(), m.cbrt(), s.cbrt());
159	Oklab {
160	l: 0.2104542553 * l_ + 0.7936177850 * m_ - 0.0040720468 * s_,
161	a: 1.9779984951 * l_ - 2.4285922050 * m_ + 0.4505937099 * s_,
162	b: 0.0259040371 * l_ + 0.7827717662 * m_ - 0.8086757660 * s_,
163	}
164	}
165
166	/// Convert from OKLab back to the nearest in-gamut sRGB.
167	///
168	/// Published precision, as in [`Rgb::to_oklab`].
169	#[allow(clippy::excessive_precision)]
170	pub fn from_oklab(c: Oklab) -> Rgb {
171	let l_ = c.l + 0.3963377774 * c.a + 0.2158037573 * c.b;
172	let m_ = c.l - 0.1055613458 * c.a - 0.0638541728 * c.b;
173	let s_ = c.l - 0.0894841775 * c.a - 1.2914855480 * c.b;
174	let (l, m, s) = (l_ * l_ * l_, m_ * m_ * m_, s_ * s_ * s_);
175	Rgb {
176	r: linear_to_srgb(4.0767416621 * l - 3.3077115913 * m + 0.2309699292 * s),
177	g: linear_to_srgb(-1.2684380046 * l + 2.6097574011 * m - 0.3413193965 * s),
178	b: linear_to_srgb(-0.0041960863 * l - 0.7034186147 * m + 1.7076147010 * s),
179	}
180	}
181	}
182
183	/// WCAG 2.x relative luminance of an sRGB color.
184	fn rel_luminance(c: Rgb) -> f32 {
185	0.2126 * srgb_to_linear(c.r) + 0.7152 * srgb_to_linear(c.g) + 0.0722 * srgb_to_linear(c.b)
186	}
187
188	/// WCAG 2.x contrast ratio between two colors, in [1, 21].
189	pub fn wcag_contrast(a: Rgb, b: Rgb) -> f32 {
190	let (la, lb) = (rel_luminance(a), rel_luminance(b));
191	let (hi, lo) = if la >= lb { (la, lb) } else { (lb, la) };
192	(hi + 0.05) / (lo + 0.05)
193	}
194
195	/// Pick black or white for legible text on `bg`, by the higher WCAG contrast
196	/// ratio (so the choice meets AA wherever the background allows it).
197	pub fn readable_on(bg: Rgb) -> Rgb {
198	let white = Rgb {
199	r: 255,
200	g: 255,
201	b: 255,
202	};
203	let black = Rgb { r: 0, g: 0, b: 0 };
204	if wcag_contrast(white, bg) >= wcag_contrast(black, bg) {
205	white
206	} else {
207	black
208	}
209	}
210
211	/// Shift OKLab lightness by `delta` (perceptually uniform). Positive lightens.
212	pub fn lighten(c: Rgb, delta: f32) -> Rgb {
213	let mut lab = c.to_oklab();
214	lab.l = (lab.l + delta).clamp(0.0, 1.0);
215	Rgb::from_oklab(lab)
216	}
217
218	/// Shift OKLab lightness down by `delta` (perceptually uniform).
219	pub fn darken(c: Rgb, delta: f32) -> Rgb {
220	lighten(c, -delta)
221	}
222
223	/// Interpolate between `a` and `b` by `t` in [0,1] in OKLab (perceptual blend).
224	pub fn mix(a: Rgb, b: Rgb, t: f32) -> Rgb {
225	let (x, y) = (a.to_oklab(), b.to_oklab());
226	Rgb::from_oklab(Oklab {
227	l: x.l + (y.l - x.l) * t,
228	a: x.a + (y.a - x.a) * t,
229	b: x.b + (y.b - x.b) * t,
230	})
231	}
232
233	// ============================================================================
234	// Tonal steps
235	// ============================================================================
236
237	/// How far a tonal step sits from the token it is a step of.
238	///
239	/// The named ratios. [`tonal`] is the same operation with the number written
240	/// out, and this is the small set of steps the vocabulary has agreed on, so a
241	/// consumer asking for "the muted form of this" names it rather than picking a
242	/// number and disagreeing with the next consumer to pick one.
243	///
244	/// The rule these encode, stated as the three-tone convention:
245	///
246	/// \| step \| what it means \|
247	/// \|------\|---------------\|
248	/// \| [`Full`](Self::Full) \| active, emphasised, the thing itself \|
249	/// \| [`Secondary`](Self::Secondary) \| inactive but usable: a control that still answers \|
250	/// \| [`Muted`](Self::Muted) \| inert: disabled, or not a control at all \|
251	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
252	pub enum Emphasis {
253	/// The token unchanged.
254	Full,
255	/// One step back. Still legible as content, not competing with `Full`.
256	Secondary,
257	/// Two steps back. Present, and saying it is not the point.
258	Muted,
259	}
260
261	impl Emphasis {
262	/// The fraction of the way to the ground this step travels.
263	///
264	/// Both numbers are the shipped corpus' own, not invented: across the 31
265	/// bundled themes, hand-authored `content.secondary` sat at a median 0.115
266	/// of the way from `content.primary` to `surface.page`, and `content.muted`
267	/// at 0.424. So the derivation reproduces what theme authors converged on
268	/// by eye, and the themes that move are the ones that were off the cluster.
269	#[must_use]
270	pub const fn ratio(self) -> f32 {
271	match self {
272	Self::Full => 0.0,
273	Self::Secondary => 0.12,
274	Self::Muted => 0.42,
275	}
276	}
277
278	/// The suffix a derived token takes, or `None` for the token itself.
279	///
280	/// `content` + [`Muted`](Self::Muted) is `content-muted`, which is the
281	/// naming every consumer already spells by hand. Grouping a family this way
282	/// is what makes `danger-muted` or `action-secondary` nameable without a
283	/// second table saying what they mean.
284	#[must_use]
285	pub const fn suffix(self) -> Option<&'static str> {
286	match self {
287	Self::Full => None,
288	Self::Secondary => Some("-secondary"),
289	Self::Muted => Some("-muted"),
290	}
291	}
292
293	/// The derived token key for `token` at this step.
294	#[must_use]
295	pub fn token(self, token: &str) -> String {
296	match self.suffix() {
297	Some(suffix) => format!("{token}{suffix}"),
298	None => token.to_string(),
299	}
300	}
301	}
302
303	/// The contrast a tonal step must clear against the token it is a step of.
304	///
305	/// A ratio says how far to travel, not how far that lands, and the two are the
306	/// same thing only when the base has room to travel in. Across the bundled
307	/// themes a derived `content.secondary` sits between 1.21 and 1.44 of its ink;
308	/// the exceptions were the two themes whose ink is `#000000`, where OKLab L is
309	/// 0, 12 percent of nothing is nothing, and the sRGB transfer curve compresses
310	/// what is left into a 3/255 move. So the floor is the bottom of the band the
311	/// healthy themes already reach, and a theme inside it does not move.
312	///
313	/// Deliberately below [`DISTINCT`]: that is the 3:1 two areas need to read as
314	/// separate, and an emphasis step is one voice quieter rather than a second
315	/// region. Asking 3:1 of it would flatten every theme's ramp into three widely
316	/// spaced greys.
317	pub const STEP_FLOOR: f32 = 1.21;
318
319	/// A tonal step of `base`, `ratio` of the way toward the `ground` it is read
320	/// against.
321	///
322	/// The numerical form of [`Emphasis`], for a consumer that wants a step the
323	/// named set does not have. `ratio` is clamped to [0,1]: past 1 the step is no
324	/// longer a step of `base` but a colour beyond the ground, which is a different
325	/// operation wearing this one's name.
326	///
327	/// # Toward the ground, not toward grey
328	///
329	/// A tonal step is a reduction in contrast against what it is read on, so it
330	/// interpolates toward the surface rather than desaturating or lightening. That
331	/// is why it takes two colours: lightening is wrong on a light theme and
332	/// darkening is wrong on a dark one, and mixing toward the ground is correct on
333	/// both without asking which theme this is. It is also why the ground is a
334	/// parameter rather than assumed — text in a well is read against the well.
335	///
336	/// # It composes
337	///
338	/// Two steps toward the same ground are one step toward that ground, since
339	/// OKLab interpolation is linear: `tonal(tonal(c, g, a), g, b)` is
340	/// `tonal(c, g, a + b - a*b)`. So a family can be derived recursively — the
341	/// muted form of a secondary is a well-defined colour and not a compounding
342	/// error — and re-deriving a token that was already derived is stable rather
343	/// than a slow slide into the background.
344	#[must_use]
345	pub fn tonal(base: Rgb, ground: Rgb, ratio: f32) -> Rgb {
346	mix(base, ground, ratio.clamp(0.0, 1.0))
347	}
348
349	/// A named tonal step of `base` against the `ground` it is read on.
350	///
351	/// [`tonal`] with [`Emphasis::ratio`], and the form to reach for: the two
352	/// spellings of "muted" a pair of consumers pick independently are the drift
353	/// this replaces.
354	#[must_use]
355	pub fn emphasized(base: Rgb, ground: Rgb, emphasis: Emphasis) -> Rgb {
356	tonal(base, ground, emphasis.ratio())
357	}
358
359	// ============================================================================
360	// Low-color terminals
361	// ============================================================================
362
363	/// The 16 colors an ANSI terminal addresses by index, in the PC/VGA
364	/// arrangement the Linux console and most emulators start from.
365	///
366	/// 0-7 are the normal colors and 8-15 the bright ones. Index 7 is a light gray
367	/// rather than white, which is the entry a themed surface usually lands on, and
368	/// index 15 is the true white.
369	///
370	/// Emulators let the user repaint all sixteen, so this is the standard
371	/// arrangement rather than a promise about any one terminal. The Linux console
372	/// keeps it, which is the case that matters: a console app cannot fall back to
373	/// 24-bit color there.
374	pub const ANSI_16: [Rgb; 16] = [
375	Rgb {
376	r: 0x00,
377	g: 0x00,
378	b: 0x00,
379	},
380	Rgb {
381	r: 0xaa,
382	g: 0x00,
383	b: 0x00,
384	},
385	Rgb {
386	r: 0x00,
387	g: 0xaa,
388	b: 0x00,
389	},
390	Rgb {
391	r: 0xaa,
392	g: 0x55,
393	b: 0x00,
394	},
395	Rgb {
396	r: 0x00,
397	g: 0x00,
398	b: 0xaa,
399	},
400	Rgb {
401	r: 0xaa,
402	g: 0x00,
403	b: 0xaa,
404	},
405	Rgb {
406	r: 0x00,
407	g: 0xaa,
408	b: 0xaa,
409	},
410	Rgb {
411	r: 0xaa,
412	g: 0xaa,
413	b: 0xaa,
414	},
415	Rgb {
416	r: 0x55,
417	g: 0x55,
418	b: 0x55,
419	},
420	Rgb {
421	r: 0xff,
422	g: 0x55,
423	b: 0x55,
424	},
425	Rgb {
426	r: 0x55,
427	g: 0xff,
428	b: 0x55,
429	},
430	Rgb {
431	r: 0xff,
432	g: 0xff,
433	b: 0x55,
434	},
435	Rgb {
436	r: 0x55,
437	g: 0x55,
438	b: 0xff,
439	},
440	Rgb {
441	r: 0xff,
442	g: 0x55,
443	b: 0xff,
444	},
445	Rgb {
446	r: 0x55,
447	g: 0xff,
448	b: 0xff,
449	},
450	Rgb {
451	r: 0xff,
452	g: 0xff,
453	b: 0xff,
454	},
455	];
456
457	/// The 256 colors an xterm-compatible terminal addresses by index, so that
458	/// entry `i` is what the terminal paints for `38;5;i`.
459	///
460	/// Three regions, and they are not equally trustworthy. 0-15 are the [`ANSI_16`]
461	/// system colors, which every emulator lets the user repaint. 16-231 are a
462	/// 6x6x6 RGB cube and 232-255 a 24-step gray ramp, and those 240 are fixed.
463	///
464	/// So a color whose whole job is to be told apart from another should quantize
465	/// against [`ANSI_240`] rather than against this table: a match landing in the
466	/// low sixteen is a match against a color the user may have moved.
467	pub const ANSI_256: [Rgb; 256] = build_ansi_256();
468
469	/// The fixed region of [`ANSI_256`]: the 6x6x6 cube and the gray ramp, without
470	/// the sixteen repaintable system colors.
471	///
472	/// Quantizing against this returns an index into this slice; add
473	/// [`ANSI_240_OFFSET`] to get the index the terminal wants.
474	pub const ANSI_240: &[Rgb] = ANSI_256.split_at(16).1;
475
476	/// What to add to an [`ANSI_240`] index to get an [`ANSI_256`] one.
477	pub const ANSI_240_OFFSET: usize = 16;
478
479	/// The twelve chromatic ANSI slots, as the intents that paint them.
480	///
481	/// Indexed 1-6 and 9-14. The hues do not depend on whether the theme is light
482	/// or dark, since red is the theme's danger tone either way, which is exactly
483	/// why the four achromatic slots are not in this table.
484	///
485	/// Lifted from Alloy's `skelgen` on 2026-07-31, which had folded three
486	/// disagreeing hand-maintained copies into one and is the reason the
487	/// arrangement is trusted. It moved here so a program that paints its own
488	/// palette at runtime, rather than reading a generated config, resolves the
489	/// same slots. Slot 14 was the one the copies disagreed on and is
490	/// `category.six`, which both the Linux console table and the retired
491	/// `vtrgb.py` had.
492	const CHROMATIC: [(usize, &str); 12] = [
493	(1, "status.danger"),
494	(2, "status.success"),
495	(3, "status.warning"),
496	(4, "status.info"),
497	(5, "category.five"),
498	(6, "category.six"),
499	(9, "action.primary"), // bright red, the theme's warm accent
500	(10, "status.success"),
501	(11, "status.warning"),
502	(12, "status.info"),
503	(13, "category.five"),
504	(14, "category.six"),
505	];
506
507	/// The four achromatic slots, 0, 7, 8 and 15, which invert with the theme.
508	///
509	/// These are the slots a naive table gets wrong. ANSI 0 is "black" and 7 is
510	/// "white", but what a terminal wants there is the darkest tone and *the
511	/// lightest tone*, and which intent that is flips with the theme's polarity. A
512	/// light theme's darkest tone is its ink; a dark theme's is its deepest
513	/// surface. Pinning slot 0 to `content.primary` reads correctly on a light
514	/// theme and hands a dark one a pale cream as "black".
515	///
516	/// Slot 7 is a surface and not a text tone, because it is what a program with
517	/// no way to name anything else draws its container on: a greeter's login card
518	/// is a light card on the darker field slot 0 paints.
519	///
520	/// Anything that is not `dark`, including `high-contrast`, follows the light
521	/// anchors.
522	fn achromatic_slot(index: usize, variant: &str) -> Option<&'static str> {
523	let dark = variant == "dark";
524	Some(match (index, dark) {
525	(0, false) => "content.primary", // darkest text tone
526	(0, true) => "surface.sunken", // darkest surface
527	(7, false) => "surface.raised", // the login card
528	(7, true) => "content.secondary", // a readable light tone
529	(8, _) => "content.muted", // muted chrome, either way
530	(15, false) => "surface.overlay", // lightest surface
531	(15, true) => "content.primary", // lightest text tone
532	_ => return None,
533	})
534	}
535
536	/// The authored intent painting ANSI slot `index` under a theme of `variant`,
537	/// as a dotted key into [`ThemeColors::colors`].
538	///
539	/// `None` for an index outside 0-15. Every slot in range resolves, so a caller
540	/// that has the intent can fill all sixteen.
541	///
542	/// This is what makes a bare console, a terminal emulator and a generated
543	/// config agree on what red means. They disagreed for as long as each kept its
544	/// own table.
545	#[must_use]
546	pub fn ansi_intent(index: usize, variant: &str) -> Option<&'static str> {
547	achromatic_slot(index, variant).or_else(\|\| {
548	CHROMATIC
549	.iter()
550	.find(\|(slot, _)\| *slot == index)
551	.map(\|(_, intent)\| *intent)
552	})
553	}
554
555	const fn build_ansi_256() -> [Rgb; 256] {
556	let mut table = [Rgb { r: 0, g: 0, b: 0 }; 256];
557
558	let mut i = 0;
559	while i < 16 {
560	table[i] = ANSI_16[i];
561	i += 1;
562	}
563
564	// The cube's six levels are not evenly spaced. The step from black to the
565	// first is more than twice any later one, which is xterm's arrangement
566	// rather than a choice available here, and it is why the darkest tones a
567	// theme can reach on 256 colors come from the gray ramp instead.
568	const LEVELS: [u8; 6] = [0, 95, 135, 175, 215, 255];
569	let mut r = 0;
570	while r < 6 {
571	let mut g = 0;
572	while g < 6 {
573	let mut b = 0;
574	while b < 6 {
575	table[16 + 36 * r + 6 * g + b] = Rgb {
576	r: LEVELS[r],
577	g: LEVELS[g],
578	b: LEVELS[b],
579	};
580	b += 1;
581	}
582	g += 1;
583	}
584	r += 1;
585	}
586
587	// 8 to 238 in steps of 10. Neither end is black or white; both of those are
588	// in the cube, so the ramp is 24 steps of gray between them rather than 24
589	// steps of the whole range.
590	let mut k = 0;
591	while k < 24 {
592	let v = 8 + 10 * k as u8;
593	table[232 + k as usize] = Rgb { r: v, g: v, b: v };
594	k += 1;
595	}
596
597	table
598	}
599
600	/// The contrast ratio two colors must clear to read as separate areas.
601	///
602	/// WCAG 2.x asks 3:1 of user interface components and graphics, which is what
603	/// a border, a rule, or a focus ring is. Text wants more, and a caller drawing
604	/// text can ask for more by checking [`wcag_contrast`] itself.
605	pub const DISTINCT: f32 = 3.0;
606
607	/// Perceptual distance between two colors, for choosing the closest of a set.
608	fn oklab_distance(a: Rgb, b: Rgb) -> f32 {
609	let (x, y) = (a.to_oklab(), b.to_oklab());
610	((x.l - y.l).powi(2) + (x.a - y.a).powi(2) + (x.b - y.b).powi(2)).sqrt()
611	}
612
613	/// Index of the entry in `palette` that looks most like `c`.
614	///
615	/// OKLab distance rather than distance in sRGB, for the same reason [`mix`]
616	/// interpolates there: sRGB's numbers are not spaced the way seeing is, so a
617	/// nearest match computed in it picks visibly wrong entries in the mid tones.
618	///
619	/// # Panics
620	///
621	/// If `palette` is empty.
622	pub fn quantize(c: Rgb, palette: &[Rgb]) -> usize {
623	assert!(!palette.is_empty(), "a palette needs at least one color");
624	let mut best = 0;
625	let mut best_distance = f32::INFINITY;
626	for (index, entry) in palette.iter().enumerate() {
627	let distance = oklab_distance(c, *entry);
628	if distance < best_distance {
629	best = index;
630	best_distance = distance;
631	}
632	}
633	best
634	}
635
636	/// Index of the entry in `palette` closest to `fg` that still reads against
637	/// `bg`.
638	///
639	/// [`quantize`] answers about one color at a time, and two colors that differ
640	/// can quantize to the same entry: a themed page and a border drawn on it are
641	/// often a few steps apart in a 24-bit theme and land together on a 16-color
642	/// terminal, leaving one flat area where there was a frame. Alloy's console
643	/// showed exactly this, and it is not a contrived pairing: a light page and the
644	/// mid-tone border derived from it both land on index 7.
645	///
646	/// So the background is quantized first, because what the border must be
647	/// distinguished from is the entry the terminal will actually paint, not the
648	/// color the theme asked for. Then the nearest entry to `fg` clearing
649	/// [`DISTINCT`] against it wins. When nothing clears it, the entry that gets
650	/// furthest does: at that point the palette cannot honor the design, and the
651	/// most legible approximation beats the closest invisible one.
652	///
653	/// Only for colors whose whole job is to be told apart from their background.
654	/// Applied to every token it would push a deliberately quiet one until it
655	/// shouted.
656	///
657	/// # Panics
658	///
659	/// If `palette` is empty.
660	pub fn quantize_against(fg: Rgb, bg: Rgb, palette: &[Rgb]) -> usize {
661	assert!(!palette.is_empty(), "a palette needs at least one color");
662	let shown = palette[quantize(bg, palette)];
663
664	let mut order: Vec<usize> = (0..palette.len()).collect();
665	order.sort_by(\|a, b\| {
666	oklab_distance(fg, palette[a]).total_cmp(&oklab_distance(fg, palette[b]))
667	});
668
669	order
670	.iter()
671	.copied()
672	.find(\|index\| wcag_contrast(palette[*index], shown) >= DISTINCT)
673	.unwrap_or_else(\|\| {
674	order
675	.iter()
676	.copied()
677	.max_by(\|a, b\| {
678	wcag_contrast(palette[a], shown).total_cmp(&wcag_contrast(palette[b], shown))
679	})
680	.expect("the palette is not empty")
681	})
682	}
683
684	// ============================================================================
685	// Intent resolution
686	// ============================================================================
687
688	/// Base intents: (TOML dotted source key, canonical token key). The token key
689	/// is the CSS-var stem (`--{token}`) and the `rgb()` lookup key.
690	///
691	/// Read straight from the loaded theme, which is not quite the same as read
692	/// from the file: `content.secondary` and `content.muted` are tonal steps of
693	/// `content.primary` and are filled in at load by [`derive_tonal_steps`], so
694	/// they arrive here already computed and take this path like any other.
695	pub const BASE_INTENTS: &[(&str, &str)] = &[
696	("surface.page", "surface-page"),
697	("surface.raised", "surface-raised"),
698	("surface.sunken", "surface-sunken"),
699	("surface.overlay", "surface-overlay"),
700	("content.primary", "content"),
701	("content.secondary", "content-secondary"),
702	("content.muted", "content-muted"),
703	("action.primary", "action"),
704	("status.danger", "danger"),
705	("status.success", "success"),
706	("status.warning", "warning"),
707	("status.info", "info"),
708	("line.border", "border"),
709	("category.one", "category-one"),
710	("category.two", "category-two"),
711	("category.three", "category-three"),
712	("category.four", "category-four"),
713	("category.five", "category-five"),
714	("category.six", "category-six"),
715	];
716
717	/// A fully resolved intent layer: every token key → concrete `#rrggbb`.
718	/// Includes both authored base intents and the computed derived intents.
719	#[derive(Debug, Clone, Serialize)]
720	#[serde(rename_all = "camelCase")]
721	pub struct SemanticTokens {
722	pub meta: ThemeMeta,
723	/// token-key → resolved hex. Stable, deterministic ordering.
724	pub intents: BTreeMap<String, String>,
725	}
726
727	impl SemanticTokens {
728	/// Resolved hex for a token key, if present.
729	pub fn hex(&self, key: &str) -> Option<&str> {
730	self.intents.get(key).map(String::as_str)
731	}
732
733	/// Resolved RGB tuple for a token key (for egui / native consumers).
734	///
735	/// `None` for a translucent token. Two intents are emitted as `rgba(...)`
736	/// rather than hex, `overlay` and `elevation`, and dropping the alpha would
737	/// hand a native consumer an opaque near-black where it asked for a scrim.
738	/// Those want [`rgba`](Self::rgba).
739	pub fn rgb(&self, key: &str) -> Option<(u8, u8, u8)> {
740	self.intents
741	.get(key)
742	.and_then(\|h\| Rgb::from_hex(h))
743	.map(Rgb::tuple)
744	}
745
746	/// Resolved RGBA tuple for a token key, alpha as 0-255.
747	///
748	/// Reads both spellings, so a caller that does not care whether an intent
749	/// happens to be translucent can use this for everything: an opaque token
750	/// comes back at 255.
751	///
752	/// It exists because a CSS consumer can take `rgba(...)` as a string
753	/// straight out of [`hex`](Self::hex) and a native one cannot. Without it
754	/// the two translucent intents are reachable from a stylesheet and from
755	/// nowhere else, which is the coupling deriving in the crate was meant to
756	/// avoid.
757	pub fn rgba(&self, key: &str) -> Option<(u8, u8, u8, u8)> {
758	let value = self.intents.get(key)?;
759	if let Some(rgb) = Rgb::from_hex(value) {
760	let (r, g, b) = rgb.tuple();
761	return Some((r, g, b, 255));
762	}
763	let inner = value.strip_prefix("rgba(")?.strip_suffix(')')?;
764	let mut parts = inner.split(',').map(str::trim);
765	let r = parts.next()?.parse().ok()?;
766	let g = parts.next()?.parse().ok()?;
767	let b = parts.next()?.parse().ok()?;
768	let alpha: f32 = parts.next()?.parse().ok()?;
769	if parts.next().is_some() \|\| !(0.0..=1.0).contains(&alpha) {
770	return None;
771	}
772	Some((r, g, b, (alpha * 255.0).round() as u8))
773	}
774	}
775
776	/// Resolve an authored theme into the full intent token set.
777	///
778	/// 1. Copy each present base intent from the authored colors.
779	/// 2. Compute the derived interactive states from the base intents, using the
780	/// same math the apps used to apply individually (so output is identical).
781	///
782	/// Each derived token is emitted only when its source intents exist, mirroring
783	/// the skip-missing behavior of the rest of the crate.
784	pub fn resolve(theme: &ThemeColors) -> SemanticTokens {
785	let mut intents: BTreeMap<String, String> = BTreeMap::new();
786
787	// 1. Base intents (authored). Copy only values that parse as a hex color and
788	// re-emit them in canonical `#rrggbb` form, so an authored value can never
789	// carry arbitrary bytes into the emitted CSS (the resolved tokens are inlined
790	// raw into a `<style>` block by the web server). A malformed value is skipped,
791	// mirroring the skip-missing behavior for absent intents.
792	for (src, token) in BASE_INTENTS {
793	if let Some(rgb) = theme.colors.get(*src).and_then(\|v\| Rgb::from_hex(v)) {
794	intents.insert((*token).to_string(), rgb.to_hex());
795	}
796	}
797
798	// Helper: parse an already-resolved token to Rgb.
799	let get = \|m: &BTreeMap<String, String>, k: &str\| m.get(k).and_then(\|h\| Rgb::from_hex(h));
800
801	// 2. Derived intents — perceptual (OKLab) steps + WCAG-picked text.
802	// Lightness deltas are in OKLab L units; mix ratios interpolate in OKLab.
803	let mut derived: Vec<(String, Rgb)> = Vec::new();
804	if let Some(action) = get(&intents, "action") {
805	derived.push(("action-hover".into(), lighten(action, 0.05)));
806	derived.push(("content-on-action".into(), readable_on(action)));
807	// The focus ring is the action colour itself, not a tint of it: a ring
808	// is a statement that the keyboard is here, and a faded one reads as a
809	// disabled control rather than an emphatic one.
810	//
811	// One ring, not one per primitive. Where the ring sits is a depth
812	// question and not a per-component choice: a well takes it inside its
813	// own edge and a raised surface takes it outside. That is one decision
814	// with two renderings rather than one decision per component, which is
815	// how the three apps ended up with three rings. This token is the one
816	// shared artifact; which thing wears it, and how it is drawn, is each
817	// renderer's own (see `makeover_layout`'s crate header, "reach, focus
818	// and the focus ring").
819	derived.push(("focus-ring".into(), action));
820	}
821	if let Some(page) = get(&intents, "surface-page") {
822	// Modal scrim: a near-black tone carrying a faint hint of the theme's
823	// hue, at 50% alpha. Anchored very dark (OKLab L=0.08) so it dims the
824	// page on light and dark themes. Emitted as rgba (not a flat hex), so
825	// it is inserted directly rather than through the hex loop below.
826	let mut o = page.to_oklab();
827	o.l = 0.08;
828	let s = Rgb::from_oklab(o);
829	intents.insert(
830	"overlay".into(),
831	format!("rgba({}, {}, {}, 0.5)", s.r, s.g, s.b),
832	);
833
834	// What a surface that FLOATS OVER the page is cast onto it with.
835	//
836	// The one intent here about a surface's relationship to the page rather
837	// than about the surface itself, which is why it is derived from `page`
838	// and not from `surface-raised`. A shadow is not the thing, it is the
839	// absence of light on what is behind the thing.
840	//
841	// SCOPE, and it is the whole point of this intent existing rather than
842	// a general "shadow": a surface that overlays the page takes this, a
843	// surface IN the page takes a bevel. Menus, toasts, popovers and
844	// dropdowns overlay. A card, a plate and a framed image do not, and
845	// reaching for this on one of those is how a pre-Platinum look survives
846	// a conversion wearing a token's name. `.raised` is the answer there.
847	//
848	// Same anchor as the scrim above and for the same reason: a tone read
849	// off the theme's hue but pinned very dark, so it reads as absence of
850	// light on a light theme and on a dark one alike. A shadow tinted to a
851	// dark theme's own lightness would not be a shadow.
852	//
853	// The alpha is the only number here that is a look decision rather than
854	// a derivation. 0.18 sits between the two literal scales it replaces:
855	// the MNW server's --shadow-2 (0.10) reads as nothing under a menu, and
856	// its --shadow-3 (0.15) was measured invisible at plate size. Geometry
857	// stays with the consumer, the way bevel thickness does.
858	intents.insert(
859	"elevation".into(),
860	format!("rgba({}, {}, {}, 0.18)", s.r, s.g, s.b),
861	);
862	}
863	if let Some(raised) = get(&intents, "surface-raised") {
864	// The two edges of a bevel: a raised control is lit from the top left,
865	// so its top and left edges take `bevel-light` and its bottom and right
866	// edges `bevel-dark`. Inverting the pair gives a pressed state and an
867	// inset well, which is what makes the idiom cheap for a consumer.
868	//
869	// Derived here rather than composed per-app because the two webviews
870	// could do it in `color-mix()` and audiofiles, which is egui, could not.
871	// Geometry (thickness, radius, which side gets which) stays app-side.
872	//
873	// The deltas are asymmetric because the eye is: an equal step down reads
874	// as a smaller change than the same step up, so the shadow is cut deeper
875	// than the highlight is raised.
876	//
877	// A face already at the top of the ramp cannot hold a highlight — the
878	// lightening clamps and the control bevels on two sides without ever
879	// resolving as lit. That is a property of the theme, not of this
880	// derivation; `bevel_edges_are_distinct_from_their_face` names the
881	// shipped themes it currently bites.
882	derived.push(("bevel-light".into(), lighten(raised, 0.14)));
883	derived.push(("bevel-dark".into(), darken(raised, 0.18)));
884
885	// An inset well: the content surface inside a raised container, so a
886	// list reads as content in a container rather than as bands on a panel.
887	// `surface-sunken` cannot serve, because a theme is free to author it
888	// darker than raised (goingson does) and a well has to go the other way.
889	//
890	// Which way is "the other way" depends on the theme, and this is the one
891	// derivation here that inverts. A well is lighter than its face on a
892	// light theme and darker on a dark one, where the bevel pair sidesteps
893	// the question by emitting both directions at once.
894	//
895	// Read the direction off `content` rather than off `Variant`. A theme
896	// whose text is dark is a theme whose surfaces are light, whatever its
897	// `variant` field claims, so this resolves correctly even when that
898	// field is wrong and it keeps the branch on measured color rather than
899	// on metadata.
900	//
901	// Deltas are asymmetric for the same reason the bevel's are, and smaller
902	// than the bevel's because a well is an area rather than an edge. The
903	// step up is the specimen's, measured: #D9DDF4 to #F3F5FD is 0.069.
904	//
905	// A face at the top of its ramp cannot hold a lighter well, the same
906	// clamp `bevel-light` hits; `well_is_visible_against_its_face` names the
907	// shipped themes where it bites.
908	if let Some(content) = get(&intents, "content") {
909	let content_is_darker = content.to_oklab().l < raised.to_oklab().l;
910	let well = if content_is_darker {
911	lighten(raised, 0.07)
912	} else {
913	darken(raised, 0.09)
914	};
915	derived.push(("surface-well".into(), well));
916	}
917	}
918	if let Some(sunken) = get(&intents, "surface-sunken") {
919	derived.push(("hover-surface".into(), sunken));
920	}
921	if let Some(border) = get(&intents, "border") {
922	derived.push(("border-strong".into(), darken(border, 0.05)));
923	}
924
925	for (token, rgb) in derived {
926	intents.insert(token, rgb.to_hex());
927	}
928
929	SemanticTokens {
930	meta: theme.meta.clone(),
931	intents,
932	}
933	}
934
935	/// Emit the resolved intent layer as CSS declarations (no selector), one
936	/// ` --token: #hex;` line each, in deterministic (BTreeMap) order.
937	pub fn intent_css_declarations(tokens: &SemanticTokens) -> String {
938	let mut out = String::new();
939	for (token, hex) in &tokens.intents {
940	out.push_str(" --");
941	out.push_str(token);
942	out.push_str(": ");
943	out.push_str(hex);
944	out.push_str(";\n");
945	}
946	out
947	}
948
949	/// Emit the resolved intent layer as a `:root { … }` block — the single TOML →
950	/// CSS mapping every web surface injects.
951	pub fn intent_css_vars(tokens: &SemanticTokens) -> String {
952	format!(":root {{\n{}}}\n", intent_css_declarations(tokens))
953	}
954
955	// ============================================================================
956	// Typography — layer 1 of the house font model.
957	//
958	// Wiki `typography-standard`. The model is three layers: an app override, the
959	// house default, then a system generic, and this is the middle one. Two needs,
960	// two names, and no others in the suite:
961	//
962	// --font-mono Quasi Mono -> monospace
963	// --font-sans Quasi Body -> sans-serif
964	//
965	// Both are cut by `quasi-type` from the Atkinson Hyperlegible superfamily plus
966	// the house glyph set. This crate does not cut them and cannot: quasi-type is
967	// `publish = false` and makeover is on crates.io, so the cut lives in each
968	// consumer's own build script (`quasi_type::cut`, taken as a git dependency,
969	// the way `shop-font` does it). What lives here is the vocabulary, which is
970	// the half that was scattered.
971	//
972	// Font is not a theme's business and none of this is themeable. A theme
973	// declares colour by role; nothing in a theme file names a face, and the two
974	// tokens below are the same in every theme. That is why they are constants
975	// rather than another section of `SemanticTokens`, and why they belong in a
976	// stylesheet generated once at build time rather than in the block that gets
977	// re-injected on a theme switch.
978	//
979	// The brand/display tier is out of scope, per product and by decision: Young
980	// Serif on MNW, Reglo in GoingsOn, Departure Mono on Alloy, audiofiles' logo
981	// face. No renderer emits them and no described screen resolves a token to
982	// one, so they keep their own `font-family` until the app-override layer
983	// lands and gives them a place to be declared.
984	// ============================================================================
985
986	/// The mono slot: code, data, identifiers, cell grids, anything monospaced.
987	pub const FONT_MONO: &str = "\"Quasi Mono\", monospace";
988
989	/// The body / UI slot. Everything that is not the mono slot or brand tier.
990	pub const FONT_SANS: &str = "\"Quasi Body\", sans-serif";
991
992	/// Filename a consumer writes the cut mono face to, under its own font URL.
993	///
994	/// `quasi-type` writes `QuasiMono[wght].woff2`, naming the variable axis the
995	/// way a font tool expects. Those brackets have to be percent-encoded to
996	/// survive a URL and are a bug waiting to be written, so the web copy takes a
997	/// plain name and the two places that have to agree — the build script that
998	/// writes the file and the `@font-face` that fetches it — agree through this
999	/// constant rather than by both spelling it out.
1000	pub const WEBFONT_MONO_FILE: &str = "QuasiMono.woff2";
1001
1002	/// Filename a consumer writes the cut body face to. See [`WEBFONT_MONO_FILE`].
1003	pub const WEBFONT_SANS_FILE: &str = "QuasiBody.woff2";
1004
1005	/// The house font tokens as CSS declarations (no selector), for a caller that
1006	/// is composing its own block.
1007	pub fn typography_css_declarations() -> String {
1008	format!(" --font-mono: {FONT_MONO};\n --font-sans: {FONT_SANS};\n")
1009	}
1010
1011	/// The house font tokens as a `:root { … }` block.
1012	///
1013	/// Inlined by surfaces that cannot link a stylesheet — the MNW embeds are the
1014	/// live case — and written to a file by everything else, through
1015	/// `makeover_build::typography_css`.
1016	pub fn typography_css_vars() -> String {
1017	format!(":root {{\n{}}}\n", typography_css_declarations())
1018	}
1019
1020	/// The `@font-face` rules for both slots, fetching from `base_url`.
1021	///
1022	/// `base_url` is the directory the consumer serves its fonts from, without a
1023	/// trailing slash: `/static/fonts` on the MNW server, `fonts` for a Tauri
1024	/// frontend loading relative to its index.
1025	///
1026	/// # `font-weight: 200 800`, which is the part that bites
1027	///
1028	/// Both faces are variable over `wght` 200-800 in one file, and the mono
1029	/// face's default instance is ExtraLight — that is upstream Atkinson's
1030	/// default and the cut keeps the axis rather than pinning a master, so a
1031	/// consumer that loads the file and takes what it opens at draws its whole UI
1032	/// at 200. Declaring the range here is what makes the browser resolve `normal`
1033	/// to 400 and `bold` to 700 instead. shop hit the same trap from the other
1034	/// side and names `wght` 400 explicitly in its shaper; this is the web's
1035	/// version of that fix, stated once for every consumer.
1036	///
1037	/// `font-display: swap` on both: the faces are 31KB and 50KB, they are cached
1038	/// hard after the first paint, and a flash of the fallback beats invisible
1039	/// text either way.
1040	pub fn font_face_css(base_url: &str) -> String {
1041	use std::fmt::Write as _;
1042
1043	let base = base_url.trim_end_matches('/');
1044	let mut out = String::new();
1045	for (family, file) in [
1046	("Quasi Mono", WEBFONT_MONO_FILE),
1047	("Quasi Body", WEBFONT_SANS_FILE),
1048	] {
1049	let _ = write!(
1050	out,
1051	"@font-face {{\n \
1052	font-family: \"{family}\";\n \
1053	src: url(\"{base}/{file}\") format(\"woff2\");\n \
1054	font-weight: 200 800;\n \
1055	font-style: normal;\n \
1056	font-display: swap;\n\
1057	}}\n\n"
1058	);
1059	}
1060	out
1061	}
1062
1063	// ============================================================================
1064	// Typography — layer 0, the app override.
1065	//
1066	// Wiki `typography-standard`, GO makeover `174ab3c1`. Layer 1 above is what
1067	// every product shares; this is the one declaration a product is allowed to
1068	// make for itself:
1069	//
1070	// layer 0 app override per product, optional MNW display -> Young Serif
1071	// layer 1 house default the quasi-* slot font quasi-mono -> Quasi Mono
1072	// layer 2 system generic one hop, no further monospace / sans-serif
1073	//
1074	// The brand tier was already exempt by decision (`cdf8ac09`), and the exemption
1075	// was enforced by those faces simply not being in the vocabulary — so each
1076	// product reached its own face through a hardcoded `font-family` and an
1077	// `@font-face` block it maintained by hand, which is the exact shape the
1078	// unification is deleting everywhere else. This turns the carve-out into a
1079	// mechanism: the per-product face is declared once, in the build script that
1080	// already writes the typography layer, and is readable as an override rather
1081	// than as a stylesheet nobody unified.
1082	//
1083	// It permits overriding `mono` and `sans` too. No product wants that today,
1084	// and a layer that only allows overriding the slot nobody describes is not a
1085	// layer, it is the exemption restated.
1086	//
1087	// One declaration per product per slot. [`Typography::with_override`]
1088	// panics on a second override of the same slot rather than letting the last
1089	// one win: a product with two answers for a slot has the vocabulary wrong, and
1090	// that is the thing to fix.
1091	//
1092	// # What a renderer does when it cannot honour one
1093	//
1094	// Declare once, renderers honour what they can. Today only the webview surface
1095	// has a face to honour at all — neither `makeover-tui` nor `makeover-immediate`
1096	// emits a `font-family` from anywhere, because the terminal owns the face in
1097	// one and the app loads its own font stack in the other. So an override is
1098	// honoured by the generated stylesheet and ignored, silently and correctly, by
1099	// the other two. A renderer that gains font control later reads
1100	// [`Typography::resolve`] rather than the CSS, which is why the resolution is
1101	// a method on the data and not a string-building detail. Loading a file needs
1102	// one thing more than the stack — the family name and the source to load it
1103	// from — so [`Typography::faces`] is the same data read the other way, and
1104	// between them an egui or TUI surface can honour an override without a
1105	// stylesheet anywhere in the path. audiofiles is the first to do it.
1106	// ============================================================================
1107
1108	/// A slot in the house font vocabulary — the unit an override replaces.
1109	///
1110	/// Three, and the third is deliberately empty by default: `display` is the
1111	/// brand tier, it has no house answer, and a product that does not override it
1112	/// leaves the token undefined so whatever the consumer wrote as a fallback
1113	/// renders. The MNW embeds rely on exactly that.
1114	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1115	pub enum FontSlot {
1116	/// Code, data, identifiers, cell grids. [`FONT_MONO`] by default.
1117	Mono,
1118	/// Body and UI text: everything that is not mono or brand. [`FONT_SANS`].
1119	Sans,
1120	/// The brand / display tier. No house default, per `cdf8ac09`.
1121	Display,
1122	}
1123
1124	impl FontSlot {
1125	/// Every slot, in the order they are emitted.
1126	pub const ALL: [FontSlot; 3] = [FontSlot::Mono, FontSlot::Sans, FontSlot::Display];
1127
1128	/// The custom property this slot is read through.
1129	pub fn token(self) -> &'static str {
1130	match self {
1131	FontSlot::Mono => "--font-mono",
1132	FontSlot::Sans => "--font-sans",
1133	FontSlot::Display => "--font-display",
1134	}
1135	}
1136
1137	/// The house stack, or `None` for the brand tier.
1138	pub fn house_default(self) -> Option<&'static str> {
1139	match self {
1140	FontSlot::Mono => Some(FONT_MONO),
1141	FontSlot::Sans => Some(FONT_SANS),
1142	FontSlot::Display => None,
1143	}
1144	}
1145	}
1146
1147	/// One `@font-face` an override brings with it.
1148	///
1149	/// A product overriding a slot usually has to ship the face too, and the two
1150	/// halves have to agree on a family name. Declaring them together is what
1151	/// makes that agreement structural rather than a string typed twice.
1152	#[derive(Debug, Clone)]
1153	pub struct FontFace {
1154	family: String,
1155	sources: Vec<String>,
1156	weight: Option<String>,
1157	style: Option<String>,
1158	}
1159
1160	impl FontFace {
1161	/// A face named `family`, fetched from `sources`.
1162	///
1163	/// Each source is either a bare filename, resolved against the
1164	/// [`Typography`] base URL, or an absolute one (`/…` or `https://…`) taken
1165	/// as written. The `format()` hint is inferred from the extension —
1166	/// `woff2`, `woff`, `ttf`, `otf` — and omitted for anything else rather
1167	/// than guessed, since a wrong hint is worse than none.
1168	pub fn new<S: Into<String>>(
1169	family: impl Into<String>,
1170	sources: impl IntoIterator<Item = S>,
1171	) -> Self {
1172	Self {
1173	family: family.into(),
1174	sources: sources.into_iter().map(Into::into).collect(),
1175	weight: None,
1176	style: None,
1177	}
1178	}
1179
1180	/// `font-weight`, as CSS writes it: `"700"`, or `"200 800"` for a variable
1181	/// axis. Omitted when unset, which means `normal`.
1182	///
1183	/// A variable face MUST name its range here for the same reason the house
1184	/// faces do: a `@font-face` with no range makes the browser resolve every
1185	/// weight to the file's default instance.
1186	#[must_use]
1187	pub fn weight(mut self, weight: impl Into<String>) -> Self {
1188	self.weight = Some(weight.into());
1189	self
1190	}
1191
1192	/// `font-style`. Omitted when unset, which means `normal`.
1193	#[must_use]
1194	pub fn style(mut self, style: impl Into<String>) -> Self {
1195	self.style = Some(style.into());
1196	self
1197	}
1198
1199	/// The family name, as the stack has to spell it.
1200	///
1201	/// For a renderer that loads faces rather than emitting CSS this is the
1202	/// name it registers the file under, and reading it here is what keeps
1203	/// that name from being typed a second time.
1204	pub fn family(&self) -> &str {
1205	&self.family
1206	}
1207
1208	/// The sources, unresolved — bare filenames as they were declared, not
1209	/// joined to any base URL. A renderer loading from disk or from an
1210	/// `include_bytes!` wants the filename; only the CSS wants the URL.
1211	pub fn sources(&self) -> &[String] {
1212	&self.sources
1213	}
1214
1215	fn css(&self, base: &str) -> String {
1216	use std::fmt::Write as _;
1217
1218	let src = self
1219	.sources
1220	.iter()
1221	.map(\|s\| {
1222	let url = if s.starts_with('/') \|\| s.contains("://") {
1223	s.clone()
1224	} else {
1225	format!("{base}/{s}")
1226	};
1227	match font_format(s) {
1228	Some(fmt) => format!("url(\"{url}\") format(\"{fmt}\")"),
1229	None => format!("url(\"{url}\")"),
1230	}
1231	})
1232	.collect::<Vec<_>>()
1233	.join(",\n ");
1234
1235	let mut out = format!(
1236	"@font-face {{\n font-family: \"{}\";\n src: {src};\n",
1237	self.family
1238	);
1239	if let Some(w) = &self.weight {
1240	let _ = writeln!(out, " font-weight: {w};");
1241	}
1242	if let Some(s) = &self.style {
1243	let _ = writeln!(out, " font-style: {s};");
1244	}
1245	out.push_str(" font-display: swap;\n}\n\n");
1246	out
1247	}
1248	}
1249
1250	/// The `format()` hint for a source, by extension. `None` when unrecognised.
1251	fn font_format(source: &str) -> Option<&'static str> {
1252	match source.rsplit('.').next()?.to_ascii_lowercase().as_str() {
1253	"woff2" => Some("woff2"),
1254	"woff" => Some("woff"),
1255	"ttf" => Some("truetype"),
1256	"otf" => Some("opentype"),
1257	_ => None,
1258	}
1259	}
1260
1261	/// One product's answer for one slot: the stack, and any faces it ships.
1262	#[derive(Debug, Clone)]
1263	pub struct FontOverride {
1264	slot: FontSlot,
1265	stack: String,
1266	faces: Vec<FontFace>,
1267	}
1268
1269	impl FontOverride {
1270	/// Point `slot` at `stack`.
1271	///
1272	/// `stack` is the CSS value the token takes, written the way the house
1273	/// stacks are: the family, then one hop to a system generic. Layer 2 is
1274	/// still one hop and no further — an override is a different answer to the
1275	/// slot, not a licence to write the fallback chain the standard deleted.
1276	pub fn new(slot: FontSlot, stack: impl Into<String>) -> Self {
1277	Self {
1278	slot,
1279	stack: stack.into(),
1280	faces: Vec::new(),
1281	}
1282	}
1283
1284	/// Ship a face with the override.
1285	#[must_use]
1286	pub fn with_face(mut self, face: FontFace) -> Self {
1287	self.faces.push(face);
1288	self
1289	}
1290
1291	/// The slot this answers.
1292	pub fn slot(&self) -> FontSlot {
1293	self.slot
1294	}
1295
1296	/// The stack it resolves to.
1297	pub fn stack(&self) -> &str {
1298	&self.stack
1299	}
1300
1301	/// The faces it ships, in declaration order.
1302	pub fn faces(&self) -> &[FontFace] {
1303	&self.faces
1304	}
1305	}
1306
1307	/// The whole typography layer for one product: the house defaults, plus
1308	/// whatever it overrides.
1309	///
1310	/// This is what a build script composes and what
1311	/// `makeover_build::typography_css_from` writes. [`typography_css_vars`] and
1312	/// [`font_face_css`] are the no-override case of it and stay for callers that
1313	/// have nothing to declare.
1314	#[derive(Debug, Clone)]
1315	pub struct Typography {
1316	base_url: String,
1317	overrides: Vec<FontOverride>,
1318	}
1319
1320	impl Typography {
1321	/// The house layer alone, fetching faces from `base_url` — the directory
1322	/// the consumer serves fonts from, with or without a trailing slash.
1323	pub fn house(base_url: impl Into<String>) -> Self {
1324	Self {
1325	base_url: base_url.into(),
1326	overrides: Vec::new(),
1327	}
1328	}
1329
1330	/// Add one product override.
1331	///
1332	/// # Panics
1333	///
1334	/// If the slot is already overridden. One declaration per product per
1335	/// slot: a second is not a merge to resolve, it is two answers to a
1336	/// question that has one, and the vocabulary is what wants fixing.
1337	#[must_use]
1338	pub fn with_override(mut self, ov: FontOverride) -> Self {
1339	assert!(
1340	!self.overrides.iter().any(\|o\| o.slot == ov.slot),
1341	"{} is overridden twice; one declaration per product per slot",
1342	ov.slot.token()
1343	);
1344	self.overrides.push(ov);
1345	self
1346	}
1347
1348	/// What `slot` resolves to under this layer, or `None` for a brand slot
1349	/// nobody overrode.
1350	///
1351	/// The resolution, for a renderer that has a face to choose rather than a
1352	/// stylesheet to emit.
1353	pub fn resolve(&self, slot: FontSlot) -> Option<&str> {
1354	self.overrides
1355	.iter()
1356	.find(\|o\| o.slot == slot)
1357	.map(\|o\| o.stack.as_str())
1358	.or_else(\|\| slot.house_default())
1359	}
1360
1361	/// The faces a product ships for `slot`, in declaration order, or an
1362	/// empty slice for a slot it did not override.
1363	///
1364	/// The other half of [`resolve`](Self::resolve), for a renderer that has
1365	/// to load a file rather than name a stack: `resolve` says which family
1366	/// wins, this says where the bytes come from and what to call them. The
1367	/// house faces are not here — they are the emitter's, and a renderer that
1368	/// wants them has them by other means.
1369	pub fn faces(&self, slot: FontSlot) -> &[FontFace] {
1370	self.overrides
1371	.iter()
1372	.find(\|o\| o.slot == slot)
1373	.map_or(&[], \|o\| o.faces())
1374	}
1375
1376	/// The `@font-face` rules: the two house faces, then each override's.
1377	pub fn font_face_css(&self) -> String {
1378	let base = self.base_url.trim_end_matches('/');
1379	let mut out = font_face_css(base);
1380	for ov in &self.overrides {
1381	for face in &ov.faces {
1382	out.push_str(&face.css(base));
1383	}
1384	}
1385	out
1386	}
1387
1388	/// The resolved tokens as CSS declarations, no selector.
1389	pub fn css_declarations(&self) -> String {
1390	use std::fmt::Write as _;
1391
1392	let mut out = String::new();
1393	for slot in FontSlot::ALL {
1394	if let Some(stack) = self.resolve(slot) {
1395	let _ = writeln!(out, " {}: {stack};", slot.token());
1396	}
1397	}
1398	out
1399	}
1400
1401	/// The resolved tokens as a `:root { … }` block.
1402	pub fn css_vars(&self) -> String {
1403	format!(":root {{\n{}}}\n", self.css_declarations())
1404	}
1405
1406	/// Faces then tokens, in the order a stylesheet wants them.
1407	pub fn css(&self) -> String {
1408	format!("{}{}", self.font_face_css(), self.css_vars())
1409	}
1410	}
1411
1412	// ============================================================================
1413	// Loading / parsing
1414	// ============================================================================
1415
1416	/// Validate a theme ID contains only safe characters (alphanumeric, hyphens, underscores).
1417	pub fn validate_theme_id(id: &str) -> Result<(), String> {
1418	if !id
1419	.chars()
1420	.all(\|c\| c.is_alphanumeric() \|\| c == '-' \|\| c == '_')
1421	{
1422	return Err(format!("Invalid theme ID: {id}"));
1423	}
1424	Ok(())
1425	}
1426
1427	/// Parse the `[meta]` section into `ThemeMeta`.
1428	///
1429	/// Falls back to the file ID as the name and `"dark"` as the variant.
1430	pub fn parse_meta(id: &str, table: &toml::Table, is_custom: bool) -> ThemeMeta {
1431	let meta = table.get("meta").and_then(\|m\| m.as_table());
1432	let name = meta
1433	.and_then(\|m\| m.get("name"))
1434	.and_then(\|v\| v.as_str())
1435	.unwrap_or(id)
1436	.to_string();
1437	let variant = meta
1438	.and_then(\|m\| m.get("variant"))
1439	.and_then(\|v\| v.as_str())
1440	.unwrap_or("dark")
1441	.to_string();
1442
1443	ThemeMeta {
1444	id: id.to_string(),
1445	name,
1446	variant,
1447	is_custom,
1448	}
1449	}
1450
1451	// ============================================================================
1452	// Choosing a theme.
1453	//
1454	// The file half of this crate was always shared; the selection half was not,
1455	// and four apps re-rolled it four ways. GoingsOn stores a "system" sentinel in
1456	// localStorage, Balanced Breakfast treats an absent value as follow-the-system
1457	// and hardcodes two theme ids as its light/dark pair, audiofiles keeps the id
1458	// in a synced SQLite table, and the Alloy console parses COLORFGBG. They also
1459	// disagreed about what a variant string means: this crate defaults a missing
1460	// one to "dark" while alloy_tui parsed an unrecognized one as light.
1461	//
1462	// What cannot be shared is the store — localStorage, a synced config table and
1463	// a TOML file are genuinely different places. What can be shared, and is here,
1464	// is the meaning: one vocabulary for variants, one encoding for "what did the
1465	// user choose", and one rule for turning that into an id that exists.
1466	// ============================================================================
1467
1468	/// A theme's kind, as declared by `meta.variant`.
1469	///
1470	/// Three, not two: one shipped theme is `high-contrast`, and an app that
1471	/// matched on light-or-dark alone would quietly file it under the wrong one.
1472	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize)]
1473	#[serde(rename_all = "kebab-case")]
1474	pub enum Variant {
1475	Light,
1476	Dark,
1477	HighContrast,
1478	}
1479
1480	impl Variant {
1481	/// The spelling used in a theme file and in [`ThemeMeta::variant`].
1482	#[must_use]
1483	pub const fn as_str(self) -> &'static str {
1484	match self {
1485	Variant::Light => "light",
1486	Variant::Dark => "dark",
1487	Variant::HighContrast => "high-contrast",
1488	}
1489	}
1490
1491	/// Read a variant string, or `None` if it names none of them.
1492	#[must_use]
1493	pub fn parse(raw: &str) -> Option<Self> {
1494	match raw {
1495	"light" => Some(Variant::Light),
1496	"dark" => Some(Variant::Dark),
1497	"high-contrast" => Some(Variant::HighContrast),
1498	_ => None,
1499	}
1500	}
1501	}
1502
1503	impl std::fmt::Display for Variant {
1504	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1505	f.write_str(self.as_str())
1506	}
1507	}
1508
1509	/// Anything unrecognized reads as dark, which is what [`parse_meta`] already
1510	/// does with a missing one. Consumers that guessed light for an unknown string
1511	/// were disagreeing with the crate that produced it.
1512	impl From<&str> for Variant {
1513	fn from(raw: &str) -> Self {
1514	Variant::parse(raw).unwrap_or(Variant::Dark)
1515	}
1516	}
1517
1518	impl ThemeMeta {
1519	/// This theme's variant as a value rather than a string.
1520	#[must_use]
1521	pub fn kind(&self) -> Variant {
1522	Variant::from(self.variant.as_str())
1523	}
1524	}
1525
1526	/// The spelling of "follow whatever the system is doing", in every store.
1527	pub const FOLLOW: &str = "system";
1528
1529	/// What the user chose, as opposed to what is being rendered.
1530	///
1531	/// The distinction is the whole point: `Follow` is a standing instruction that
1532	/// resolves differently as the ambient mode changes, and a `Fixed` id is an
1533	/// answer that does not. An app that stored only the rendered id could not tell
1534	/// the two apart the next time the system flipped to dark.
1535	#[derive(Debug, Clone, PartialEq, Eq, Default)]
1536	pub enum ThemeSelection {
1537	/// Track the ambient light/dark mode.
1538	#[default]
1539	Follow,
1540	/// Always this theme.
1541	Fixed(String),
1542	}
1543
1544	impl ThemeSelection {
1545	/// Read a stored selection. An empty or absent value is [`Follow`], which
1546	/// is what an app with nothing saved yet should do.
1547	///
1548	/// [`Follow`]: ThemeSelection::Follow
1549	#[must_use]
1550	pub fn parse(raw: Option<&str>) -> Self {
1551	match raw.map(str::trim) {
1552	None \| Some("" \| FOLLOW) => ThemeSelection::Follow,
1553	Some(id) => ThemeSelection::Fixed(id.to_string()),
1554	}
1555	}
1556
1557	/// The string to persist, whatever the store is.
1558	#[must_use]
1559	pub fn as_str(&self) -> &str {
1560	match self {
1561	ThemeSelection::Follow => FOLLOW,
1562	ThemeSelection::Fixed(id) => id,
1563	}
1564	}
1565
1566	/// Turn a selection into a theme id that exists.
1567	///
1568	/// `ambient` is the light/dark mode the app learned however it can: a
1569	/// `prefers-color-scheme` media query, an OS appearance API, `COLORFGBG`
1570	/// from a terminal. `available` is what [`list_themes_from_dirs`] found.
1571	///
1572	/// A `Fixed` id that is no longer on disk falls through to the same path as
1573	/// `Follow` rather than being returned anyway. Themes are deletable in
1574	/// three of the four apps, and handing back an id that will fail to load
1575	/// only moves the error somewhere less helpful.
1576	///
1577	/// The fallback chain is: the app's own default for the ambient mode if it
1578	/// is installed, then any installed theme of that variant, then the app's
1579	/// default regardless. The last step means this always returns something,
1580	/// and an app with no theme directory at all gets the id it ships with and
1581	/// the load error it would have had anyway.
1582	#[must_use]
1583	pub fn resolve(
1584	&self,
1585	ambient: Variant,
1586	defaults: &ThemeDefaults,
1587	available: &[ThemeMeta],
1588	) -> String {
1589	let installed = \|id: &str\| available.iter().any(\|meta\| meta.id == id);
1590
1591	if let ThemeSelection::Fixed(id) = self
1592	&& installed(id)
1593	{
1594	return id.clone();
1595	}
1596
1597	let preferred = defaults.for_variant(ambient);
1598	if installed(preferred) {
1599	return preferred.to_string();
1600	}
1601	available
1602	.iter()
1603	.find(\|meta\| meta.kind() == ambient)
1604	.map_or_else(\|\| preferred.to_string(), \|meta\| meta.id.clone())
1605	}
1606	}
1607
1608	impl std::fmt::Display for ThemeSelection {
1609	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1610	f.write_str(self.as_str())
1611	}
1612	}
1613
1614	/// The themes an app falls back to, one per ambient mode.
1615	///
1616	/// App-specific on purpose: which theme is "the app's own" is the app's
1617	/// identity, not this crate's business. What is shared is everything around it.
1618	#[derive(Debug, Clone)]
1619	pub struct ThemeDefaults {
1620	light: String,
1621	dark: String,
1622	high_contrast: Option<String>,
1623	}
1624
1625	impl ThemeDefaults {
1626	pub fn new(light: impl Into<String>, dark: impl Into<String>) -> Self {
1627	Self {
1628	light: light.into(),
1629	dark: dark.into(),
1630	high_contrast: None,
1631	}
1632	}
1633
1634	/// Name a theme for a high-contrast ambient mode. Without one, that mode
1635	/// falls back to the dark default, which is the safer of the two to read.
1636	#[must_use]
1637	pub fn high_contrast(mut self, id: impl Into<String>) -> Self {
1638	self.high_contrast = Some(id.into());
1639	self
1640	}
1641
1642	#[must_use]
1643	pub fn for_variant(&self, variant: Variant) -> &str {
1644	match variant {
1645	Variant::Light => &self.light,
1646	Variant::Dark => &self.dark,
1647	Variant::HighContrast => self.high_contrast.as_ref().unwrap_or(&self.dark),
1648	}
1649	}
1650	}
1651
1652	// ============================================================================
1653	// Where themes are looked for.
1654	//
1655	// Four apps built this vector by hand, two of them byte-for-byte identically,
1656	// and one of them built it backwards: the Alloy console pushed the user's own
1657	// directory first, under a comment saying "highest precedence first", when both
1658	// consumers of the vector resolve last wins. A user's custom theme lost to
1659	// the packaged one of the same id.
1660	//
1661	// Hence a builder that names the tiers rather than a function taking a vector.
1662	// The precedence is stated once, here, and a caller cannot express it backwards
1663	// because the order is not theirs to choose.
1664	// ============================================================================
1665
1666	/// Builds the search path [`load_theme`] and [`list_themes_from_dirs`] take.
1667	///
1668	/// Tiers are added in whatever order is convenient and always end up in
1669	/// precedence order: the user's own themes win, then whatever the system
1670	/// ships, then whatever the app bundles.
1671	///
1672	/// A directory that does not exist is dropped rather than carried, so callers
1673	/// can offer every tier they might have without checking each one.
1674	#[derive(Debug, Default, Clone)]
1675	pub struct ThemeDirs {
1676	bundled: Vec<PathBuf>,
1677	system: Vec<PathBuf>,
1678	custom: Option<PathBuf>,
1679	}
1680
1681	impl ThemeDirs {
1682	#[must_use]
1683	pub fn new() -> Self {
1684	Self::default()
1685	}
1686
1687	/// Themes the app ships with. Lowest precedence.
1688	///
1689	/// Takes more than one because a Tauri app has two: the bundled resource
1690	/// directory in production, and the tree `build.rs` materialized for a
1691	/// `cargo run` that has no resource directory at all.
1692	#[must_use]
1693	pub fn bundled(mut self, dir: Option<PathBuf>) -> Self {
1694	self.bundled.extend(dir);
1695	self
1696	}
1697
1698	/// Themes the machine ships, from an image or a package. Overrides bundled.
1699	#[must_use]
1700	pub fn system(mut self, dir: Option<PathBuf>) -> Self {
1701	self.system.extend(dir);
1702	self
1703	}
1704
1705	/// The user's own themes. Highest precedence, and the only tier flagged
1706	/// custom, which is what makes them exportable and deletable.
1707	#[must_use]
1708	pub fn custom(mut self, dir: Option<PathBuf>) -> Self {
1709	self.custom = dir;
1710	self
1711	}
1712
1713	/// The search path, lowest precedence first.
1714	#[must_use]
1715	pub fn build(self) -> Vec<(PathBuf, bool)> {
1716	let mut dirs = Vec::new();
1717	for dir in self.bundled.into_iter().chain(self.system) {
1718	if dir.is_dir() {
1719	dirs.push((dir, false));
1720	}
1721	}
1722	if let Some(dir) = self.custom
1723	&& dir.is_dir()
1724	{
1725	dirs.push((dir, true));
1726	}
1727	dirs
1728	}
1729	}
1730
1731	/// Extract the intent color sections into a flat `HashMap` with dotted keys
1732	/// like `"surface.page"`, `"status.danger"`, `"category.one"`.
1733	///
1734	/// The tonal steps of `content.primary` are filled in here rather than read, by
1735	/// [`derive_tonal_steps`]. Anything a theme authored under those keys is
1736	/// replaced.
1737	pub fn extract_colors(table: &toml::Table) -> HashMap<String, String> {
1738	let mut colors = HashMap::new();
1739	for section in COLOR_SECTIONS {
1740	if let Some(sect) = table.get(*section).and_then(\|s\| s.as_table()) {
1741	for (key, val) in sect {
1742	if let Some(color) = val.as_str() {
1743	colors.insert(format!("{section}.{key}"), color.to_string());
1744	}
1745	}
1746	}
1747	}
1748	derive_tonal_steps(&mut colors);
1749	colors
1750	}
1751
1752	/// Fill in the tonal steps of `content.primary`, overwriting whatever the theme
1753	/// authored under those keys.
1754	///
1755	/// # Why they are not authored
1756	///
1757	/// `content.secondary` and `content.muted` are not independent colours. They are
1758	/// the ink, one step and two steps back, and a theme that names them separately
1759	/// is stating three times something it stated once — which is how three of the
1760	/// bundled themes came to author a `secondary` lighter than their own
1761	/// `primary` (nord, solarized-dark) or identical to it (dracula), inverting the
1762	/// emphasis ramp the whole vocabulary rests on. Deriving them makes
1763	/// `content` > `content-secondary` > `content-muted` true by construction in
1764	/// every theme, including one a user writes.
1765	///
1766	/// Applied at load rather than in [`resolve`] so that there is one answer: the
1767	/// resolved token layer, the ANSI table ([`ansi_intent`] reads authored keys),
1768	/// and every consumer holding a [`ThemeColors`] all see the same value. A
1769	/// derivation visible from only one of those is how a terminal and a webview
1770	/// come to disagree about what muted means.
1771	///
1772	/// Both keys need `content.primary` and `surface.page` to exist and parse. When
1773	/// either is missing the step is skipped and anything authored is left where it
1774	/// is, mirroring the skip-missing behaviour of the rest of the crate — a
1775	/// half-written theme keeps whatever it has rather than losing it.
1776	///
1777	/// # The ratio is a starting point, not the answer
1778	///
1779	/// Each step is pushed further toward the page until it clears [`STEP_FLOOR`]
1780	/// against the ink, so what the theme gets is a step that can be seen rather
1781	/// than a step of the agreed size. The two are the same number in every bundled
1782	/// theme but the two with a pure-black ink, where the ratio has no range to
1783	/// travel in and the nominal step lands 3/255 from where it started.
1784	pub fn derive_tonal_steps<S: std::hash::BuildHasher>(colors: &mut HashMap<String, String, S>) {
1785	let ink = colors.get("content.primary").and_then(\|v\| Rgb::from_hex(v));
1786	let page = colors.get("surface.page").and_then(\|v\| Rgb::from_hex(v));
1787	let (Some(ink), Some(page)) = (ink, page) else {
1788	return;
1789	};
1790	// Each step starts no nearer than the one before it landed, so pushing
1791	// secondary out cannot carry it past muted and invert the ramp.
1792	let mut reached = 0.0;
1793	for (key, step) in [
1794	("content.secondary", Emphasis::Secondary),
1795	("content.muted", Emphasis::Muted),
1796	] {
1797	let (color, ratio) = step_clearing_floor(ink, page, step.ratio().max(reached));
1798	reached = ratio;
1799	colors.insert(key.to_string(), color.to_hex());
1800	}
1801	}
1802
1803	/// The step `from` of the way from `ink` to `page`, pushed toward `page` until
1804	/// it clears [`STEP_FLOOR`] against the ink it is a step of. Returns the colour
1805	/// and the ratio it was found at.
1806	///
1807	/// A forward scan rather than a solve, because it wants the first ratio that
1808	/// clears: contrast against the base rises with the distance travelled, but it
1809	/// rises through sRGB's transfer curve and OKLab's chroma path, and a bisection
1810	/// would trust a monotonicity nothing here guarantees.
1811	///
1812	/// Travel stops at the ground. A theme whose ink and page are the same colour
1813	/// has no step to take, and the ground is the honest answer — nothing past it
1814	/// is a step of the ink any more.
1815	fn step_clearing_floor(ink: Rgb, page: Rgb, from: f32) -> (Rgb, f32) {
1816	// Finer than 8-bit sRGB can resolve on the shortest ramp in the corpus, so
1817	// the scan never steps over the first colour that clears.
1818	const PROBE: f32 = 0.005;
1819	let mut ratio = from.clamp(0.0, 1.0);
1820	loop {
1821	let color = tonal(ink, page, ratio);
1822	if wcag_contrast(color, ink) >= STEP_FLOOR \|\| ratio >= 1.0 {
1823	return (color, ratio);
1824	}
1825	ratio = (ratio + PROBE).min(1.0);
1826	}
1827	}
1828
1829	/// Scan directories for `.toml` theme files and return metadata for each.
1830	///
1831	/// Directories are checked in order; later entries override earlier ones by ID.
1832	/// Each entry in `dirs` is `(path, is_custom)`.
1833	pub fn list_themes_from_dirs(dirs: &[(PathBuf, bool)]) -> Vec<ThemeMeta> {
1834	let mut seen: HashMap<String, ThemeMeta> = HashMap::new();
1835
1836	for (dir, is_custom) in dirs {
1837	let Ok(entries) = std::fs::read_dir(dir) else {
1838	continue;
1839	};
1840
1841	for entry in entries {
1842	let Ok(entry) = entry else {
1843	continue;
1844	};
1845	let path = entry.path();
1846	if path.extension().and_then(\|e\| e.to_str()) != Some("toml") {
1847	continue;
1848	}
1849
1850	let id = path
1851	.file_stem()
1852	.and_then(\|s\| s.to_str())
1853	.unwrap_or_default()
1854	.to_string();
1855
1856	let Ok(content) = std::fs::read_to_string(&path) else {
1857	continue;
1858	};
1859	let table: toml::Table = match content.parse() {
1860	Ok(t) => t,
1861	Err(_) => continue,
1862	};
1863
1864	seen.insert(id.clone(), parse_meta(&id, &table, *is_custom));
1865	}
1866	}
1867
1868	let mut themes: Vec<ThemeMeta> = seen.into_values().collect();
1869	themes.sort_by(\|a, b\| a.name.cmp(&b.name));
1870	themes
1871	}
1872
1873	/// Find a theme file by ID in the given directories.
1874	///
1875	/// Checks directories in reverse order so the highest-priority directory wins.
1876	/// Returns `(path, is_custom)` or `None` if not found.
1877	pub fn find_theme_path(dirs: &[(PathBuf, bool)], id: &str) -> Option<(PathBuf, bool)> {
1878	let filename = format!("{id}.toml");
1879
1880	for (dir, is_custom) in dirs.iter().rev() {
1881	let path = dir.join(&filename);
1882	if path.is_file() {
1883	return Some((path, *is_custom));
1884	}
1885	}
1886
1887	None
1888	}
1889
1890	/// Parse a complete theme (metadata + colors) from raw TOML content, with no
1891	/// filesystem access. For callers that embed themes at compile time.
1892	pub fn parse_theme_str(id: &str, content: &str, is_custom: bool) -> Result<ThemeColors, String> {
1893	validate_theme_id(id)?;
1894	let table: toml::Table = content
1895	.parse()
1896	.map_err(\|e\| format!("Failed to parse theme '{id}': {e}"))?;
1897	let meta = parse_meta(id, &table, is_custom);
1898	let colors = extract_colors(&table);
1899	Ok(ThemeColors { meta, colors })
1900	}
1901
1902	/// Load a complete theme (metadata + colors) by ID from the given directories.
1903	pub fn load_theme(dirs: &[(PathBuf, bool)], id: &str) -> Result<ThemeColors, String> {
1904	validate_theme_id(id)?;
1905
1906	let (path, is_custom) =
1907	find_theme_path(dirs, id).ok_or_else(\|\| format!("Theme '{id}' not found"))?;
1908
1909	let content = std::fs::read_to_string(&path)
1910	.map_err(\|e\| format!("Failed to read {}: {}", path.display(), e))?;
1911
1912	let table: toml::Table = content
1913	.parse()
1914	.map_err(\|e\| format!("Failed to parse {}: {}", path.display(), e))?;
1915
1916	let meta = parse_meta(id, &table, is_custom);
1917	let colors = extract_colors(&table);
1918
1919	Ok(ThemeColors { meta, colors })
1920	}
1921
1922	/// Load a theme and resolve it to the full intent token set in one step.
1923	pub fn load_semantic(dirs: &[(PathBuf, bool)], id: &str) -> Result<SemanticTokens, String> {
1924	Ok(resolve(&load_theme(dirs, id)?))
1925	}
1926
1927	/// Import a theme TOML file into the custom themes directory.
1928	///
1929	/// Validates that the file is parseable TOML with at least one intent color
1930	/// section, then copies it to `custom_dir/{id}.toml`. Returns the theme metadata.
1931	pub fn import_theme(source_path: &Path, custom_dir: &Path) -> Result<ThemeMeta, String> {
1932	let content = std::fs::read_to_string(source_path)
1933	.map_err(\|e\| format!("Failed to read {}: {}", source_path.display(), e))?;
1934
1935	let table: toml::Table = content.parse().map_err(\|e\| format!("Invalid TOML: {e}"))?;
1936
1937	let has_colors = COLOR_SECTIONS
1938	.iter()
1939	.any(\|s\| table.get(*s).and_then(\|v\| v.as_table()).is_some());
1940	if !has_colors {
1941	return Err(format!(
1942	"Theme file must have at least one color section ({})",
1943	COLOR_SECTIONS.join(", ")
1944	));
1945	}
1946
1947	let id = source_path
1948	.file_stem()
1949	.and_then(\|s\| s.to_str())
1950	.ok_or("Invalid file name")?
1951	.to_string();
1952	validate_theme_id(&id)?;
1953
1954	std::fs::create_dir_all(custom_dir)
1955	.map_err(\|e\| format!("Failed to create {}: {}", custom_dir.display(), e))?;
1956
1957	let dest = custom_dir.join(format!("{id}.toml"));
1958	std::fs::copy(source_path, &dest).map_err(\|e\| format!("Failed to copy theme: {e}"))?;
1959
1960	Ok(parse_meta(&id, &table, true))
1961	}
1962
1963	/// Delete a custom theme by ID.
1964	///
1965	/// Only operates on `custom_dir` — bundled themes are not deletable through
1966	/// this entry point.
1967	pub fn delete_theme(custom_dir: &Path, id: &str) -> Result<(), String> {
1968	validate_theme_id(id)?;
1969
1970	let path = custom_dir.join(format!("{id}.toml"));
1971	if !path.is_file() {
1972	return Err(format!("Custom theme '{id}' not found"));
1973	}
1974
1975	std::fs::remove_file(&path).map_err(\|e\| format!("Failed to delete {}: {}", path.display(), e))
1976	}
1977
1978	/// A four-color preview for theme thumbnails: the representative swatch from
1979	/// each of the principal roles.
1980	#[derive(Debug, Clone, Serialize)]
1981	#[serde(rename_all = "camelCase")]
1982	pub struct ThemePreview {
1983	pub meta: ThemeMeta,
1984	/// Page background (`surface.page`).
1985	pub background: Option<String>,
1986	/// Body text (`content.primary`).
1987	pub foreground: Option<String>,
1988	/// Brand/interactive color (`action.primary`).
1989	pub accent: Option<String>,
1990	/// Divider/outline color (`line.border`).
1991	pub border: Option<String>,
1992	}
1993
1994	fn color_at(table: &toml::Table, section: &str, key: &str) -> Option<String> {
1995	table
1996	.get(section)
1997	.and_then(\|s\| s.as_table())
1998	.and_then(\|s\| s.get(key))
1999	.and_then(\|v\| v.as_str())
2000	.map(std::string::ToString::to_string)
2001	}
2002
2003	/// Load just the preview swatches for a theme — for UI thumbnails.
2004	pub fn load_theme_preview(dirs: &[(PathBuf, bool)], id: &str) -> Result<ThemePreview, String> {
2005	validate_theme_id(id)?;
2006
2007	let (path, is_custom) =
2008	find_theme_path(dirs, id).ok_or_else(\|\| format!("Theme '{id}' not found"))?;
2009
2010	let content = std::fs::read_to_string(&path)
2011	.map_err(\|e\| format!("Failed to read {}: {}", path.display(), e))?;
2012
2013	let table: toml::Table = content
2014	.parse()
2015	.map_err(\|e\| format!("Failed to parse {}: {}", path.display(), e))?;
2016
2017	Ok(ThemePreview {
2018	meta: parse_meta(id, &table, is_custom),
2019	background: color_at(&table, "surface", "page"),
2020	foreground: color_at(&table, "content", "primary"),
2021	accent: color_at(&table, "action", "primary"),
2022	border: color_at(&table, "line", "border"),
2023	})
2024	}
2025
2026	/// Export a theme to a user-chosen path.
2027	pub fn export_theme(dirs: &[(PathBuf, bool)], id: &str, dest_path: &Path) -> Result<(), String> {
2028	validate_theme_id(id)?;
2029
2030	let (source, _) = find_theme_path(dirs, id).ok_or_else(\|\| format!("Theme '{id}' not found"))?;
2031
2032	std::fs::copy(&source, dest_path).map_err(\|e\| format!("Failed to export theme: {e}"))?;
2033
2034	Ok(())
2035	}
2036
2037	/// The themes this crate ships, embedded at compile time.
2038	///
2039	/// `include_dir` is an implementation detail: the public API hands back plain
2040	/// `(id, toml_source)` pairs, so how the data is embedded can change without
2041	/// a breaking release.
2042	static EMBEDDED: include_dir::Dir<'static> =
2043	include_dir::include_dir!("$CARGO_MANIFEST_DIR/themes");
2044
2045	/// The themes this crate ships, as `(id, toml_source)` pairs.
2046	///
2047	/// This is the path-free way to reach the bundled set, for consumers that
2048	/// cannot rely on a directory existing at runtime: a crate pulled from
2049	/// crates.io lives in a registry checkout whose location is not knowable at
2050	/// compile time, so `include_dir!` and asset-bundling globs in the depending
2051	/// crate have nothing stable to point at. Embedding here and re-exporting the
2052	/// contents gives them one source of truth without a path.
2053	///
2054	/// Ordering follows the embedded directory and is not guaranteed; collect and
2055	/// sort by id where a stable order matters (a theme picker, say).
2056	pub fn embedded_themes() -> impl Iterator<Item = (&'static str, &'static str)> {
2057	EMBEDDED.files().filter_map(\|file\| {
2058	let path = file.path();
2059	if path.extension().and_then(\|e\| e.to_str()) != Some("toml") {
2060	return None;
2061	}
2062	let id = path.file_stem()?.to_str()?;
2063	Some((id, file.contents_utf8()?))
2064	})
2065	}
2066
2067	/// The theme directory this crate ships, for use as a build-from-source
2068	/// fallback.
2069	///
2070	/// Resolves against `makeover`'s own manifest directory, fixed at compile
2071	/// time, so it works from a path dependency and from a cargo git checkout
2072	/// alike. Installed systems should put their packaged theme directory ahead
2073	/// of this in the search path; this is the entry that keeps `cargo run` in a
2074	/// fresh clone from coming up with no themes at all.
2075	///
2076	/// Returns `None` when the directory is absent — a cargo cache that has been
2077	/// cleaned, or a vendored copy that dropped the data — so callers degrade to
2078	/// their remaining search path rather than failing.
2079	pub fn bundled_themes_dir() -> Option<PathBuf> {
2080	let themes = Path::new(env!("CARGO_MANIFEST_DIR")).join("themes");
2081	if themes.is_dir() { Some(themes) } else { None }
2082	}
2083
2084	#[cfg(test)]
2085	mod tests {
2086	use super::*;
2087	use std::fs;
2088
2089	// ---- id validation ----
2090
2091	#[test]
2092	fn validate_theme_id_alphanumeric() {
2093	assert!(validate_theme_id("darkmode").is_ok());
2094	assert!(validate_theme_id("Theme123").is_ok());
2095	}
2096
2097	#[test]
2098	fn validate_theme_id_hyphens_underscores() {
2099	assert!(validate_theme_id("dark-mode").is_ok());
2100	assert!(validate_theme_id("my_theme_v2").is_ok());
2101	}
2102
2103	#[test]
2104	fn validate_theme_id_rejects_path_traversal() {
2105	assert!(validate_theme_id("../etc/passwd").is_err());
2106	assert!(validate_theme_id("foo/bar").is_err());
2107	assert!(validate_theme_id("theme.toml").is_err());
2108	}
2109
2110	// ---- low-color terminals ----
2111
2112	#[test]
2113	fn the_ansi_palette_is_sixteen_distinct_colors() {
2114	let mut seen: Vec<(u8, u8, u8)> = ANSI_16.iter().map(\|c\| c.tuple()).collect();
2115	seen.sort_unstable();
2116	seen.dedup();
2117	assert_eq!(seen.len(), 16);
2118	}
2119
2120	// ---- the intent-to-slot table ----
2121
2122	// Sixteen slots, every one of them answered. A caller filling a terminal
2123	// palette has no fallback for a hole: the slot would keep whatever the
2124	// emulator started with, and one raw ANSI colour in a themed table is more
2125	// obviously wrong than all sixteen would be.
2126	#[test]
2127	fn every_ansi_slot_names_an_intent_on_either_polarity() {
2128	for variant in ["light", "dark", "high-contrast"] {
2129	for index in 0..16 {
2130	assert!(
2131	ansi_intent(index, variant).is_some(),
2132	"slot {index} unanswered on {variant}"
2133	);
2134	}
2135	assert_eq!(ansi_intent(16, variant), None);
2136	}
2137	}
2138
2139	// The property the four achromatic slots exist to hold: 0 is the darkest
2140	// tone the theme offers and 15 the lightest, in either polarity. A table
2141	// that pins slot 0 to `content.primary` passes this on a light theme and
2142	// inverts on a dark one, which is the bug the polarity split fixes.
2143	#[test]
2144	fn ansi_zero_is_darker_than_ansi_fifteen_on_either_polarity() {
2145	for id in ["akari-dawn", "akari-night"] {
2146	let theme = bundled(id);
2147	let slot = \|i: usize\| -> Rgb {
2148	let key = ansi_intent(i, &theme.meta.variant).expect("in range");
2149	Rgb::from_hex(theme.colors.get(key).expect("theme carries it")).expect("valid hex")
2150	};
2151	assert!(
2152	rel_luminance(slot(0)) < rel_luminance(slot(15)),
2153	"{id}: ANSI 0 {} should be darker than ANSI 15 {}",
2154	slot(0).to_hex(),
2155	slot(15).to_hex(),
2156	);
2157	}
2158	}
2159
2160	// The pair a greeter draws with: its container on 7, its text on 0. If
2161	// those collapse the login screen is one flat block, and slot 7 being a
2162	// surface rather than a text tone is what keeps them apart.
2163	#[test]
2164	fn the_container_slot_and_the_text_slot_stay_legible() {
2165	for id in ["akari-dawn", "akari-night"] {
2166	let theme = bundled(id);
2167	let slot = \|i: usize\| -> Rgb {
2168	let key = ansi_intent(i, &theme.meta.variant).expect("in range");
2169	Rgb::from_hex(theme.colors.get(key).expect("theme carries it")).expect("valid hex")
2170	};
2171	let contrast = wcag_contrast(slot(0), slot(7));
2172	assert!(contrast >= 4.5, "{id}: ANSI 0 on ANSI 7 is {contrast:.2}:1");
2173	}
2174	}
2175
2176	// The hues do not move with polarity. Red is the theme's danger tone on a
2177	// light theme and on a dark one, which is why only four slots are in the
2178	// polarity table at all.
2179	#[test]
2180	fn the_chromatic_slots_do_not_vary_with_polarity() {
2181	for index in [1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 14] {
2182	assert_eq!(
2183	ansi_intent(index, "light"),
2184	ansi_intent(index, "dark"),
2185	"slot {index} moved with polarity"
2186	);
2187	}
2188	}
2189
2190	fn bundled(id: &str) -> ThemeColors {
2191	let dir = bundled_themes_dir().expect("makeover ships its themes");
2192	load_theme(&[(dir, false)], id).expect("the akari pair ships")
2193	}
2194
2195	#[test]
2196	fn quantize_picks_the_obvious_entry() {
2197	let black = Rgb { r: 0, g: 0, b: 0 };
2198	let white = Rgb {
2199	r: 255,
2200	g: 255,
2201	b: 255,
2202	};
2203	assert_eq!(quantize(black, &ANSI_16), 0);
2204	assert_eq!(quantize(white, &ANSI_16), 15);
2205	}
2206
2207	// Nearest-entry quantization is per-color, so two colors a theme keeps
2208	// apart can arrive as one. These two are both closest to the palette's
2209	// light gray, and a border drawn in one on a page painted the other is not
2210	// drawn at all.
2211	#[test]
2212	fn two_colors_can_quantize_to_one_entry() {
2213	let page = Rgb::from_hex("#a8a8a8").unwrap();
2214	let border = Rgb::from_hex("#b4b4b4").unwrap();
2215
2216	assert_eq!(quantize(page, &ANSI_16), quantize(border, &ANSI_16));
2217	assert_ne!(
2218	quantize_against(border, page, &ANSI_16),
2219	quantize(page, &ANSI_16)
2220	);
2221	}
2222
2223	#[test]
2224	fn quantize_against_keeps_the_border_off_the_page() {
2225	let page = Rgb::from_hex("#e4ded6").unwrap();
2226	let border = Rgb::from_hex("#7f786d").unwrap();
2227
2228	let shown_page = ANSI_16[quantize(page, &ANSI_16)];
2229	let shown_border = ANSI_16[quantize_against(border, page, &ANSI_16)];
2230
2231	assert!(
2232	wcag_contrast(shown_border, shown_page) >= DISTINCT,
2233	"border {} on page {} is {:.2}:1",
2234	shown_border.to_hex(),
2235	shown_page.to_hex(),
2236	wcag_contrast(shown_border, shown_page)
2237	);
2238	}
2239
2240	// A color that already reads against its background is left where it is,
2241	// so this can be applied without redesigning what already worked.
2242	#[test]
2243	fn quantize_against_leaves_a_readable_color_alone() {
2244	let page = Rgb::from_hex("#e4ded6").unwrap();
2245	let text = Rgb::from_hex("#1a1816").unwrap();
2246
2247	assert_eq!(
2248	quantize_against(text, page, &ANSI_16),
2249	quantize(text, &ANSI_16)
2250	);
2251	}
2252
2253	// With nothing in the palette to satisfy the request, the most legible
2254	// entry is the answer. Returning the nearest one would return the
2255	// background itself, which is the failure this function exists to avoid.
2256	#[test]
2257	fn an_impossible_palette_gets_the_most_legible_entry() {
2258	let page = Rgb::from_hex("#ffffff").unwrap();
2259	let border = Rgb::from_hex("#fefefe").unwrap();
2260	let palette = [
2261	Rgb::from_hex("#ffffff").unwrap(),
2262	Rgb::from_hex("#fdfdfd").unwrap(),
2263	];
2264
2265	let chosen = palette[quantize_against(border, page, &palette)];
2266	assert_eq!(chosen.to_hex(), "#fdfdfd");
2267	}
2268
2269	// ---- meta ----
2270
2271	#[test]
2272	fn parse_meta_with_name_and_variant() {
2273	let table: toml::Table = "[meta]\nname = \"Nord\"\nvariant = \"light\"\n"
2274	.parse()
2275	.unwrap();
2276	let meta = parse_meta("nord", &table, false);
2277	assert_eq!(meta.id, "nord");
2278	assert_eq!(meta.name, "Nord");
2279	assert_eq!(meta.variant, "light");
2280	assert!(!meta.is_custom);
2281	}
2282
2283	#[test]
2284	fn parse_meta_defaults_to_id_and_dark() {
2285	let table: toml::Table = "".parse().unwrap();
2286	let meta = parse_meta("fallback", &table, true);
2287	assert_eq!(meta.name, "fallback");
2288	assert_eq!(meta.variant, "dark");
2289	assert!(meta.is_custom);
2290	}
2291
2292	// ---- color math (formulas must match the apps they came from) ----
2293
2294	#[test]
2295	fn rgb_hex_roundtrip() {
2296	assert_eq!(
2297	Rgb::from_hex("#6196FF").unwrap(),
2298	Rgb {
2299	r: 0x61,
2300	g: 0x96,
2301	b: 0xff
2302	}
2303	);
2304	assert_eq!(
2305	Rgb::from_hex("#abc").unwrap(),
2306	Rgb {
2307	r: 0xaa,
2308	g: 0xbb,
2309	b: 0xcc
2310	}
2311	);
2312	assert_eq!(
2313	Rgb {
2314	r: 0x61,
2315	g: 0x96,
2316	b: 0xff
2317	}
2318	.to_hex(),
2319	"#6196ff"
2320	);
2321	assert!(Rgb::from_hex("not-a-color").is_none());
2322	}
2323
2324	#[test]
2325	fn oklab_roundtrips_within_tolerance() {
2326	for hex in ["#6196ff", "#2e3440", "#ffffff", "#000000", "#c0392b"] {
2327	let c = Rgb::from_hex(hex).unwrap();
2328	let back = Rgb::from_oklab(c.to_oklab());
2329	// Gamut round-trip is near-exact (±1 per channel from rounding).
2330	assert!((c.r as i16 - back.r as i16).abs() <= 1, "{hex} r");
2331	assert!((c.g as i16 - back.g as i16).abs() <= 1, "{hex} g");
2332	assert!((c.b as i16 - back.b as i16).abs() <= 1, "{hex} b");
2333	}
2334	}
2335
2336	#[test]
2337	fn wcag_contrast_known_pairs() {
2338	let white = Rgb {
2339	r: 255,
2340	g: 255,
2341	b: 255,
2342	};
2343	let black = Rgb { r: 0, g: 0, b: 0 };
2344	assert!((wcag_contrast(white, black) - 21.0).abs() < 0.01);
2345	assert!((wcag_contrast(white, white) - 1.0).abs() < 0.01);
2346	}
2347
2348	#[test]
2349	fn readable_on_picks_by_wcag() {
2350	assert_eq!(
2351	readable_on(Rgb {
2352	r: 255,
2353	g: 255,
2354	b: 255
2355	}),
2356	Rgb { r: 0, g: 0, b: 0 }
2357	);
2358	assert_eq!(
2359	readable_on(Rgb { r: 0, g: 0, b: 0 }),
2360	Rgb {
2361	r: 255,
2362	g: 255,
2363	b: 255
2364	}
2365	);
2366	// A light blue action -> black text reads better.
2367	let action = Rgb::from_hex("#6196ff").unwrap();
2368	assert_eq!(readable_on(action), Rgb { r: 0, g: 0, b: 0 });
2369	}
2370
2371	#[test]
2372	fn lighten_darken_move_oklab_lightness() {
2373	let c = Rgb::from_hex("#6196ff").unwrap();
2374	let l0 = c.to_oklab().l;
2375	assert!(lighten(c, 0.05).to_oklab().l > l0);
2376	assert!(darken(c, 0.05).to_oklab().l < l0);
2377	}
2378
2379	#[test]
2380	fn mix_endpoints_and_midpoint() {
2381	let a = Rgb::from_hex("#000000").unwrap();
2382	let b = Rgb::from_hex("#6196ff").unwrap();
2383	assert_eq!(mix(a, b, 0.0), a);
2384	assert_eq!(mix(a, b, 1.0), b);
2385	// Midpoint sits between the endpoints in OKLab lightness.
2386	let mid = mix(a, b, 0.5).to_oklab().l;
2387	assert!(mid > a.to_oklab().l && mid < b.to_oklab().l);
2388	}
2389
2390	// ---- extract + resolve ----
2391
2392	fn nord_toml() -> &'static str {
2393	r##"
2394	[meta]
2395	name = "Nord"
2396	variant = "dark"
2397
2398	[surface]
2399	page = "#2e3440"
2400	raised = "#3b4252"
2401	sunken = "#434c5e"
2402	overlay = "#3b4252"
2403
2404	[content]
2405	primary = "#d8dee9"
2406	secondary = "#e5e9f0"
2407	muted = "#616e88"
2408
2409	[action]
2410	primary = "#81a1c1"
2411
2412	[status]
2413	danger = "#bf616a"
2414	success = "#a3be8c"
2415	warning = "#ebcb8b"
2416	info = "#88c0d0"
2417
2418	[line]
2419	border = "#4c566a"
2420
2421	[category]
2422	one = "#bf616a"
2423	two = "#a3be8c"
2424	three = "#81a1c1"
2425	four = "#ebcb8b"
2426	five = "#b48ead"
2427	six = "#88c0d0"
2428	"##
2429	}
2430
2431	#[test]
2432	fn extract_colors_reads_intent_sections() {
2433	let table: toml::Table = nord_toml().parse().unwrap();
2434	let colors = extract_colors(&table);
2435	assert_eq!(colors.get("surface.page").unwrap(), "#2e3440");
2436	assert_eq!(colors.get("content.primary").unwrap(), "#d8dee9");
2437	assert_eq!(colors.get("action.primary").unwrap(), "#81a1c1");
2438	assert_eq!(colors.get("status.danger").unwrap(), "#bf616a");
2439	assert_eq!(colors.get("line.border").unwrap(), "#4c566a");
2440	assert_eq!(colors.get("category.five").unwrap(), "#b48ead");
2441	assert_eq!(colors.len(), 19);
2442	}
2443
2444	#[test]
2445	fn resolve_base_intents_passthrough() {
2446	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2447	let t = resolve(&theme);
2448	assert_eq!(t.hex("surface-page"), Some("#2e3440"));
2449	assert_eq!(t.hex("content"), Some("#d8dee9")); // content.primary -> content
2450	// Not a passthrough: a tonal step of the ink, whatever the file said.
2451	assert_eq!(
2452	t.hex("content-muted").unwrap(),
2453	emphasized(
2454	Rgb::from_hex("#d8dee9").unwrap(),
2455	Rgb::from_hex("#2e3440").unwrap(),
2456	Emphasis::Muted
2457	)
2458	.to_hex()
2459	);
2460	assert_eq!(t.hex("action"), Some("#81a1c1"));
2461	assert_eq!(t.hex("danger"), Some("#bf616a"));
2462	assert_eq!(t.hex("border"), Some("#4c566a"));
2463	assert_eq!(t.hex("category-five"), Some("#b48ead"));
2464	}
2465
2466	#[test]
2467	fn a_tonal_step_lands_between_its_base_and_its_ground() {
2468	let ink = Rgb::from_hex("#d8dee9").unwrap();
2469	let page = Rgb::from_hex("#2e3440").unwrap();
2470	for step in [Emphasis::Full, Emphasis::Secondary, Emphasis::Muted] {
2471	let out = emphasized(ink, page, step).to_oklab().l;
2472	assert!(
2473	out <= ink.to_oklab().l && out >= page.to_oklab().l,
2474	"{step:?} left the interval between the ink and the page"
2475	);
2476	}
2477	assert_eq!(emphasized(ink, page, Emphasis::Full).to_hex(), ink.to_hex());
2478	}
2479
2480	#[test]
2481	fn tonal_steps_compose_rather_than_compound() {
2482	// Two steps toward one ground are one step toward it, which is what
2483	// makes deriving a family recursively well-defined. Within a rounding
2484	// step, since each hop lands back in 8-bit sRGB.
2485	let ink = Rgb::from_hex("#d8dee9").unwrap();
2486	let page = Rgb::from_hex("#2e3440").unwrap();
2487	let (a, b) = (0.12f32, 0.42f32);
2488	let twice = tonal(tonal(ink, page, a), page, b);
2489	let once = tonal(ink, page, a + b - a * b);
2490	let (x, y) = (twice.tuple(), once.tuple());
2491	for (l, r) in [(x.0, y.0), (x.1, y.1), (x.2, y.2)] {
2492	assert!(l.abs_diff(r) <= 1, "{twice:?} is not {once:?}");
2493	}
2494	}
2495
2496	#[test]
2497	fn a_ratio_outside_the_interval_is_clamped_rather_than_extrapolated() {
2498	let ink = Rgb::from_hex("#d8dee9").unwrap();
2499	let page = Rgb::from_hex("#2e3440").unwrap();
2500	assert_eq!(tonal(ink, page, -1.0).to_hex(), ink.to_hex());
2501	assert_eq!(tonal(ink, page, 2.0).to_hex(), page.to_hex());
2502	}
2503
2504	#[test]
2505	fn a_derived_token_key_is_the_family_plus_the_step() {
2506	assert_eq!(Emphasis::Muted.token("content"), "content-muted");
2507	assert_eq!(Emphasis::Secondary.token("content"), "content-secondary");
2508	assert_eq!(Emphasis::Full.token("content"), "content");
2509	// The point of the suffix being a property of the step: any family can
2510	// be grouped the same way without a second table saying what it means.
2511	assert_eq!(Emphasis::Muted.token("danger"), "danger-muted");
2512	}
2513
2514	#[test]
2515	fn every_shipped_theme_ramps_one_way() {
2516	// The property authoring the steps separately could not hold: three
2517	// themes had shipped a secondary lighter than their own primary, so a
2518	// renderer reading the emphasis order got the reverse of it.
2519	for (id, toml) in embedded_themes() {
2520	let theme = parse_theme_str(id, toml, false).unwrap();
2521	let t = resolve(&theme);
2522	let page = Rgb::from_hex(t.hex("surface-page").unwrap()).unwrap();
2523	let steps = ["content", "content-secondary", "content-muted"]
2524	.map(\|k\| wcag_contrast(Rgb::from_hex(t.hex(k).unwrap()).unwrap(), page));
2525	assert!(
2526	steps[0] > steps[1] && steps[1] > steps[2],
2527	"{id}: emphasis does not fall monotonically: {steps:?}"
2528	);
2529	}
2530	}
2531
2532	#[test]
2533	fn every_shipped_theme_takes_a_visible_first_step() {
2534	// The property that was missing when 2.6.0 derived these, and the
2535	// reason a pure-black ink shipped a secondary 3/255 away from it: the
2536	// ramp falling monotonically says nothing about how far it falls, and
2537	// a step nobody can see is not a step.
2538	for (id, toml) in embedded_themes() {
2539	let theme = parse_theme_str(id, toml, false).unwrap();
2540	let t = resolve(&theme);
2541	let ink = Rgb::from_hex(t.hex("content").unwrap()).unwrap();
2542	let secondary = Rgb::from_hex(t.hex("content-secondary").unwrap()).unwrap();
2543	let step = wcag_contrast(ink, secondary);
2544	assert!(
2545	step >= STEP_FLOOR,
2546	"{id}: secondary is {step:.2} from its ink, under the {STEP_FLOOR} floor"
2547	);
2548	}
2549	}
2550
2551	#[test]
2552	fn an_authored_emphasis_step_does_not_survive_loading() {
2553	// `nord_toml` still authors both, because a user's theme file might and
2554	// the answer has to be the same one.
2555	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2556	assert_ne!(theme.colors.get("content.muted").unwrap(), "#616e88");
2557	assert_ne!(theme.colors.get("content.secondary").unwrap(), "#e5e9f0");
2558	}
2559
2560	#[test]
2561	fn a_theme_with_no_page_keeps_what_it_authored() {
2562	// Skip-missing: there is nothing to read the step against, so the step
2563	// is not taken and a half-written theme does not lose a colour.
2564	let mut colors = HashMap::new();
2565	colors.insert("content.primary".to_string(), "#d8dee9".to_string());
2566	colors.insert("content.muted".to_string(), "#616e88".to_string());
2567	derive_tonal_steps(&mut colors);
2568	assert_eq!(colors.get("content.muted").unwrap(), "#616e88");
2569	}
2570
2571	#[test]
2572	fn resolve_derived_intents() {
2573	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2574	let t = resolve(&theme);
2575	let action = Rgb::from_hex("#81a1c1").unwrap();
2576	let page = Rgb::from_hex("#2e3440").unwrap();
2577	let _ = page;
2578	assert_eq!(
2579	t.hex("action-hover").unwrap(),
2580	lighten(action, 0.05).to_hex()
2581	);
2582	assert_eq!(
2583	t.hex("content-on-action").unwrap(),
2584	readable_on(action).to_hex()
2585	);
2586	assert_eq!(t.hex("focus-ring"), Some("#81a1c1"));
2587	assert_eq!(t.hex("hover-surface"), Some("#434c5e")); // = surface.sunken
2588	// Pruned by the usage audit (0 consumers): action-active, the *-surface
2589	// tints, selection, row-stripe. Apps that need them derive inline via
2590	// the shared mix().
2591	assert!(t.hex("action-active").is_none());
2592	assert!(t.hex("danger-surface").is_none());
2593	assert!(t.hex("selection").is_none());
2594	assert!(t.hex("row-stripe").is_none());
2595	}
2596
2597	#[test]
2598	fn resolve_bevel_intents() {
2599	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2600	let t = resolve(&theme);
2601	let raised = Rgb::from_hex("#3b4252").unwrap();
2602	assert_eq!(
2603	t.hex("bevel-light").unwrap(),
2604	lighten(raised, 0.14).to_hex()
2605	);
2606	assert_eq!(t.hex("bevel-dark").unwrap(), darken(raised, 0.18).to_hex());
2607	}
2608
2609	// A bevel is two edges around one face, so both edges have to be visibly off
2610	// that face or the control never resolves as lit. The lightening clamps at
2611	// the top of the ramp, which means a theme authoring a white raised surface
2612	// gets a highlight identical to the surface it is meant to sit on.
2613	//
2614	// The list is asserted rather than merely reported so that changing a theme
2615	// has to come here and say so. Shrinking it is the fix; growing it is a
2616	// regression in the theme, not in this derivation.
2617	#[test]
2618	fn bevel_edges_are_distinct_from_their_face() {
2619	const CANNOT_BEVEL: &[&str] = &["neobrute", "oxocarbon-light"];
2620
2621	let mut degenerate: Vec<String> = Vec::new();
2622	for (id, source) in embedded_themes() {
2623	let theme = parse_theme_str(id, source, false).unwrap();
2624	let t = resolve(&theme);
2625	let Some(raised) = t.hex("surface-raised") else {
2626	continue;
2627	};
2628	let light = t.hex("bevel-light").expect("raised implies bevel-light");
2629	let dark = t.hex("bevel-dark").expect("raised implies bevel-dark");
2630	if light == raised \|\| dark == raised {
2631	degenerate.push(id.to_string());
2632	}
2633	}
2634	degenerate.sort();
2635
2636	assert_eq!(
2637	degenerate, CANNOT_BEVEL,
2638	"themes whose raised surface cannot hold both bevel edges"
2639	);
2640	}
2641
2642	// The well inverts by theme, so assert both directions explicitly rather
2643	// than only the one the light themes happen to take.
2644	#[test]
2645	fn resolve_well_intent_follows_the_content_direction() {
2646	// nord is dark: light text on a dark raised surface, so the well goes
2647	// down and away from the text.
2648	let dark = resolve(&parse_theme_str("nord", nord_toml(), false).unwrap());
2649	let dark_raised = Rgb::from_hex("#3b4252").unwrap();
2650	assert_eq!(
2651	dark.hex("surface-well").unwrap(),
2652	darken(dark_raised, 0.09).to_hex()
2653	);
2654
2655	// The shipped light themes take the other branch.
2656	let goingson = embedded_themes()
2657	.into_iter()
2658	.find(\|(id, _)\| *id == "goingson")
2659	.expect("goingson is embedded")
2660	.1;
2661	let light = resolve(&parse_theme_str("goingson", goingson, false).unwrap());
2662	let light_raised = light
2663	.hex("surface-raised")
2664	.and_then(Rgb::from_hex)
2665	.expect("goingson authors a raised surface");
2666	assert_eq!(
2667	light.hex("surface-well").unwrap(),
2668	lighten(light_raised, 0.07).to_hex()
2669	);
2670	}
2671
2672	// A well is a fill, not an edge, so the only thing that makes it read is
2673	// being a different color from the surface it is cut into.
2674	//
2675	// Same shape and the same asserted-list discipline as
2676	// `bevel_edges_are_distinct_from_their_face`, and it bites the same two
2677	// themes for the same reason: a raised surface already at the top of the
2678	// ramp has nothing lighter to go to.
2679	#[test]
2680	fn well_is_distinct_from_its_face() {
2681	const CANNOT_WELL: &[&str] = &["neobrute", "oxocarbon-light"];
2682
2683	let mut degenerate: Vec<String> = Vec::new();
2684	for (id, source) in embedded_themes() {
2685	let theme = parse_theme_str(id, source, false).unwrap();
2686	let t = resolve(&theme);
2687	let Some(raised) = t.hex("surface-raised") else {
2688	continue;
2689	};
2690	let well = t.hex("surface-well").expect("raised implies surface-well");
2691	if well == raised {
2692	degenerate.push(id.to_string());
2693	}
2694	}
2695	degenerate.sort();
2696
2697	assert_eq!(
2698	degenerate, CANNOT_WELL,
2699	"themes whose raised surface cannot hold a well"
2700	);
2701	}
2702
2703	// Distinct is not the same as visible. A face near the top of the ramp
2704	// clamps partway rather than exactly, which yields a well that differs from
2705	// its face by a hex digit and by nothing the eye can find. `rosepine-dawn`
2706	// authors raised at L=0.987 and gets 0.009 of the 0.07 it asked for.
2707	//
2708	// Worth a separate test from the one above because the fix differs: an
2709	// exactly-degenerate theme needs its raised surface off the ramp end, while
2710	// these need it merely lowered. Both fixes are the theme's, not this
2711	// derivation's, which is why the list is asserted rather than warned about.
2712	#[test]
2713	fn well_is_visible_against_its_face() {
2714	// Below this, the well and its face are the same surface to a reader.
2715	const MIN_DELTA_L: f32 = 0.02;
2716	const CANNOT_HOLD_A_VISIBLE_WELL: &[&str] =
2717	&["neobrute", "oxocarbon-light", "rosepine-dawn"];
2718
2719	let mut invisible: Vec<String> = Vec::new();
2720	for (id, source) in embedded_themes() {
2721	let theme = parse_theme_str(id, source, false).unwrap();
2722	let t = resolve(&theme);
2723	let (Some(raised), Some(well)) = (
2724	t.hex("surface-raised").and_then(Rgb::from_hex),
2725	t.hex("surface-well").and_then(Rgb::from_hex),
2726	) else {
2727	continue;
2728	};
2729	if (well.to_oklab().l - raised.to_oklab().l).abs() < MIN_DELTA_L {
2730	invisible.push(id.to_string());
2731	}
2732	}
2733	invisible.sort();
2734
2735	assert_eq!(
2736	invisible, CANNOT_HOLD_A_VISIBLE_WELL,
2737	"themes whose well is too close to its face to read as one"
2738	);
2739	}
2740
2741	// The three tests above each measure a derived color against the face it was
2742	// derived from, so a theme can pass all of them and still have nothing lift
2743	// off anything: the face itself sits on the page, and that relationship is
2744	// the one a bevel needs in order to read as an object rather than as a
2745	// rectangle with decorated edges. makenot.work passed all three and could
2746	// not hold a bevel, which is what this covers.
2747	//
2748	// The threshold is picked against the ramps already ruled on rather than
2749	// against a round number. makenot.work shipped at 0.024 and was invisible,
2750	// was tried at 0.036 and rejected as marginal on badges and chips, and was
2751	// accepted at 0.058; goingson and audiofiles sit at 0.119 and 0.065. Every
2752	// ramp judged inadequate is below 0.036 and every one judged adequate is
2753	// above 0.058, so the line goes in the gap between them. Note the unit: this
2754	// is oklab L on 0 to 1, not the CIE L* on 0 to 100 that the theme files quote
2755	// in their comments, and the two are not interchangeable.
2756	//
2757	// Most of the list is imported palettes, which were authored for syntax
2758	// highlighting and owe our depth model nothing. Failing here says a theme
2759	// cannot hold a bevel, not that it is wrong. Shrinking the list is the fix;
2760	// growing it is a regression in the theme, not in this derivation.
2761	//
2762	// tokyonight left the list on 2026-08-15, and it is the only entry that could
2763	// leave without a judgment call about someone else's palette. Its page and
2764	// raised were the identical hex, so it had no ramp at all rather than a
2765	// shallow one, and the fix is upstream's own `bg_highlight` (#292e42, 0.079
2766	// above the page) rather than a color we picked. The other nineteen are
2767	// shallow ramps in published palettes, which is a different claim, and they
2768	// stay deferred until every app is migrated and eyeballed.
2769	#[test]
2770	fn raised_is_distinct_from_page() {
2771	// Below this, a raised surface and the page under it are one surface to
2772	// a reader, whichever direction the theme ramps in.
2773	const MIN_DELTA_L: f32 = 0.05;
2774	const CANNOT_LIFT_OFF_THE_PAGE: &[&str] = &[
2775	"akari-dawn",
2776	"akari-night",
2777	"ayu-light",
2778	"ayu-mirage",
2779	"catppuccin-latte",
2780	"catppuccin-mocha",
2781	"dawnfox",
2782	"dracula",
2783	"everforest",
2784	"flatwhite",
2785	"gruvbox-light",
2786	"neobrute",
2787	"one-dark",
2788	"oxocarbon-dark",
2789	"oxocarbon-light",
2790	"poimandres",
2791	"rosepine",
2792	"rosepine-dawn",
2793	"solarized-dark",
2794	];
2795
2796	let mut flat: Vec<String> = Vec::new();
2797	for (id, source) in embedded_themes() {
2798	let theme = parse_theme_str(id, source, false).unwrap();
2799	let t = resolve(&theme);
2800	let (Some(page), Some(raised)) = (
2801	t.hex("surface-page").and_then(Rgb::from_hex),
2802	t.hex("surface-raised").and_then(Rgb::from_hex),
2803	) else {
2804	continue;
2805	};
2806	if (raised.to_oklab().l - page.to_oklab().l).abs() < MIN_DELTA_L {
2807	flat.push(id.to_string());
2808	}
2809	}
2810	flat.sort();
2811
2812	assert_eq!(
2813	flat, CANNOT_LIFT_OFF_THE_PAGE,
2814	"themes whose raised surface is too close to the page to lift off it"
2815	);
2816	}
2817
2818	// What the bevel pair does on a sixteen-color terminal, measured across the
2819	// shipped set rather than assumed. Two results, both load-bearing for a
2820	// consumer that has to render one there.
2821	//
2822	// Exactly one edge survives, never both. A raised face quantizes onto one of
2823	// the palette's three grays, and the palette is too coarse to hold anything
2824	// between that entry and its neighbour, so whichever edge is pushed toward
2825	// the end of the ramp the face already sits on lands back on the face. Light
2826	// themes and most dark ones keep the shadow and lose the highlight; a face
2827	// that quantizes to black keeps the highlight and loses the shadow.
2828	//
2829	// So a low-color consumer draws the single edge it can render, on the side
2830	// the palette left it, rather than a bevel that resolves on two sides.
2831	//
2832	// And `quantize_against` is the wrong function for this pair, though it is
2833	// the right one for a border. It answers "nearest entry that clears DISTINCT
2834	// against the background", which has no notion of direction, so both edges
2835	// are pushed onto the same contrasting entry and the bevel inverts on one
2836	// side. Plain `quantize` keeps them apart and in the right order.
2837	#[test]
2838	fn a_sixteen_color_terminal_gets_one_bevel_edge_and_not_two() {
2839	for (id, source) in embedded_themes() {
2840	let theme = parse_theme_str(id, source, false).unwrap();
2841	let t = resolve(&theme);
2842	let (Some(face), Some(light), Some(dark)) = (
2843	t.hex("surface-raised").and_then(Rgb::from_hex),
2844	t.hex("bevel-light").and_then(Rgb::from_hex),
2845	t.hex("bevel-dark").and_then(Rgb::from_hex),
2846	) else {
2847	continue;
2848	};
2849
2850	let face_index = quantize(face, &ANSI_16);
2851	let light_survives = quantize(light, &ANSI_16) != face_index;
2852	let dark_survives = quantize(dark, &ANSI_16) != face_index;
2853	assert!(
2854	light_survives != dark_survives,
2855	"{id}: expected exactly one bevel edge to survive 16 colors, \
2856	highlight {light_survives} shadow {dark_survives}"
2857	);
2858
2859	// Direction-blind, so it collapses the pair it is asked to separate.
2860	assert_eq!(
2861	quantize_against(light, face, &ANSI_16),
2862	quantize_against(dark, face, &ANSI_16),
2863	"{id}: quantize_against is expected to be unusable for a bevel pair"
2864	);
2865	}
2866	}
2867
2868	// 256 colors is where the bevel starts working. At 16 every shipped theme
2869	// loses an edge; here all but the five whose raised surface sits at the very
2870	// top of the ramp keep both, and those five fail for the reason they fail in
2871	// truecolor rather than for a palette reason.
2872	//
2873	// Three of them cannot bevel at any depth, so they are the
2874	// `bevel_edges_are_distinct_from_their_face` set. The other two are new here:
2875	// they hold a highlight in 24-bit, but not one wide enough to survive
2876	// rounding onto the cube.
2877	#[test]
2878	fn two_hundred_fifty_six_colors_keep_both_bevel_edges() {
2879	const LOSES_AN_EDGE: &[&str] = &[
2880	"gruvbox-light",
2881	"neobrute",
2882	"oxocarbon-light",
2883	"rosepine-dawn",
2884	];
2885
2886	let mut lost: Vec<String> = Vec::new();
2887	for (id, source) in embedded_themes() {
2888	let theme = parse_theme_str(id, source, false).unwrap();
2889	let t = resolve(&theme);
2890	let (Some(face), Some(light), Some(dark)) = (
2891	t.hex("surface-raised").and_then(Rgb::from_hex),
2892	t.hex("bevel-light").and_then(Rgb::from_hex),
2893	t.hex("bevel-dark").and_then(Rgb::from_hex),
2894	) else {
2895	continue;
2896	};
2897
2898	// Against the fixed region, which is what a consumer should use: a
2899	// match in the low sixteen is a match against a repaintable color.
2900	let f = quantize(face, ANSI_240);
2901	let l = quantize(light, ANSI_240);
2902	let d = quantize(dark, ANSI_240);
2903	if l == f \|\| d == f \|\| l == d {
2904	lost.push(id.to_string());
2905	}
2906	}
2907	lost.sort();
2908
2909	assert_eq!(
2910	lost, LOSES_AN_EDGE,
2911	"themes that cannot hold a two-tone bevel on a 256-color terminal"
2912	);
2913	}
2914
2915	#[test]
2916	fn the_256_table_has_its_three_regions() {
2917	// Index is the escape-sequence index, so the low sixteen must match.
2918	assert_eq!(ANSI_256[..16], ANSI_16);
2919	// The cube's corners, at both ends and one interior level.
2920	assert_eq!(ANSI_256[16].tuple(), (0, 0, 0));
2921	assert_eq!(ANSI_256[231].tuple(), (255, 255, 255));
2922	assert_eq!(ANSI_256[16 + 36 * 2 + 6 * 3 + 4].tuple(), (135, 175, 215));
2923	// The gray ramp runs 8 to 238 and contains neither black nor white.
2924	assert_eq!(ANSI_256[232].tuple(), (8, 8, 8));
2925	assert_eq!(ANSI_256[255].tuple(), (238, 238, 238));
2926	// The fixed region is the table minus the repaintable colors.
2927	assert_eq!(ANSI_240.len(), 240);
2928	assert_eq!(ANSI_240[0], ANSI_256[ANSI_240_OFFSET]);
2929	}
2930
2931	#[test]
2932	fn resolve_overlay_is_dark_translucent_scrim() {
2933	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2934	let t = resolve(&theme);
2935	let overlay = t.hex("overlay").unwrap();
2936	assert!(
2937	overlay.starts_with("rgba("),
2938	"overlay is translucent: {overlay}"
2939	);
2940	assert!(overlay.ends_with(", 0.5)"));
2941	// The scrim tone is anchored very dark regardless of theme.
2942	let inner = overlay
2943	.trim_start_matches("rgba(")
2944	.trim_end_matches(", 0.5)");
2945	let parts: Vec<u8> = inner.split(", ").map(\|p\| p.parse().unwrap()).collect();
2946	let scrim = Rgb {
2947	r: parts[0],
2948	g: parts[1],
2949	b: parts[2],
2950	};
2951	assert!(scrim.to_oklab().l < 0.2, "scrim must be near-black");
2952	}
2953
2954	/// Every shipped theme derives it, on both polarities, and it is always a
2955	/// near-black translucent tone. A shadow tinted to a dark theme's own
2956	/// lightness would not read as one.
2957	#[test]
2958	fn elevation_is_a_near_black_cast_on_every_theme() {
2959	for (id, source) in embedded_themes() {
2960	let theme = parse_theme_str(id, source, false).unwrap();
2961	let t = resolve(&theme);
2962	let Some(elevation) = t.hex("elevation") else {
2963	panic!("{id} derives no elevation");
2964	};
2965	assert!(
2966	elevation.starts_with("rgba(") && elevation.ends_with(", 0.18)"),
2967	"{id}: elevation is translucent: {elevation}"
2968	);
2969	let inner = elevation
2970	.trim_start_matches("rgba(")
2971	.trim_end_matches(", 0.18)");
2972	let parts: Vec<u8> = inner.split(", ").map(\|p\| p.parse().unwrap()).collect();
2973	let cast = Rgb {
2974	r: parts[0],
2975	g: parts[1],
2976	b: parts[2],
2977	};
2978	assert!(
2979	cast.to_oklab().l < 0.2,
2980	"{id}: a cast shadow must be near-black, got {elevation}"
2981	);
2982	}
2983	}
2984
2985	/// The scrim and the cast share an anchor and differ only in weight. Stated
2986	/// as a test because the two are easy to drift apart, and a scrim that
2987	/// stopped matching the shadow under the thing it dims would show.
2988	#[test]
2989	fn elevation_and_the_scrim_are_the_same_tone() {
2990	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2991	let t = resolve(&theme);
2992	let scrim = t.hex("overlay").unwrap();
2993	let cast = t.hex("elevation").unwrap();
2994	assert_eq!(
2995	scrim.trim_end_matches(", 0.5)"),
2996	cast.trim_end_matches(", 0.18)"),
2997	);
2998	}
2999
3000	/// The accessor that makes a translucent intent reachable from something
3001	/// that is not a stylesheet. Both spellings, and an opaque token answers
3002	/// 255 so a caller need not know which kind it asked for.
3003	#[test]
3004	fn rgba_reads_both_spellings() {
3005	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
3006	let t = resolve(&theme);
3007
3008	let (_, _, _, opaque) = t.rgba("surface-page").expect("page is a hex token");
3009	assert_eq!(opaque, 255);
3010
3011	let (r, g, b, alpha) = t.rgba("elevation").expect("elevation is translucent");
3012	assert_eq!(alpha, 46, "0.18 of 255");
3013	assert_eq!(t.rgb("elevation"), None, "rgb declines to drop the alpha");
3014
3015	let (sr, sg, sb, scrim) = t.rgba("overlay").expect("overlay is translucent");
3016	assert_eq!((sr, sg, sb), (r, g, b), "one tone, two weights");
3017	assert_eq!(scrim, 128);
3018	}
3019
3020	#[test]
3021	fn resolve_drops_non_hex_base_intent() {
3022	// A base intent that isn't a hex color must never reach the resolved
3023	// token set (it would otherwise be inlined verbatim into a <style>
3024	// block). Skipped like a missing intent; valid siblings survive.
3025	let theme = parse_theme_str(
3026	"x",
3027	"[surface]\npage = \"</style><script>alert(1)</script>\"\n[content]\nprimary = \"#111111\"\n",
3028	false,
3029	)
3030	.unwrap();
3031	let t = resolve(&theme);
3032	assert!(
3033	t.hex("surface-page").is_none(),
3034	"non-hex base intent leaked"
3035	);
3036	assert_eq!(t.hex("content").unwrap(), "#111111");
3037	// The injected markup appears in no resolved value.
3038	assert!(!t.intents.values().any(\|v\| v.contains('<')));
3039	}
3040
3041	#[test]
3042	fn resolve_skips_derived_when_source_missing() {
3043	// No [action] => no action-derived tokens.
3044	let theme = parse_theme_str(
3045	"x",
3046	"[surface]\npage = \"#000000\"\n[line]\nborder = \"#222222\"\n",
3047	false,
3048	)
3049	.unwrap();
3050	let t = resolve(&theme);
3051	assert!(t.hex("action").is_none());
3052	assert!(t.hex("action-hover").is_none());
3053	assert!(t.hex("selection").is_none());
3054	assert_eq!(
3055	t.hex("border-strong").unwrap(),
3056	darken(Rgb::from_hex("#222222").unwrap(), 0.05).to_hex()
3057	);
3058	}
3059
3060	#[test]
3061	fn rgb_accessor_for_native_consumers() {
3062	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
3063	let t = resolve(&theme);
3064	assert_eq!(t.rgb("action"), Some((0x81, 0xa1, 0xc1)));
3065	assert_eq!(t.rgb("nonexistent"), None);
3066	}
3067
3068	// ---- css emit ----
3069
3070	#[test]
3071	fn intent_css_vars_wraps_root_and_includes_tokens() {
3072	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
3073	let css = intent_css_vars(&resolve(&theme));
3074	assert!(css.starts_with(":root {\n"));
3075	assert!(css.contains(" --surface-page: #2e3440;\n"));
3076	assert!(css.contains(" --danger: #bf616a;\n"));
3077	assert!(css.contains(" --action-hover: "));
3078	assert!(css.trim_end().ends_with('}'));
3079	}
3080
3081	// ---- typography ----
3082
3083	#[test]
3084	fn the_font_tokens_are_two_names_and_each_ends_at_a_system_generic() {
3085	let css = typography_css_vars();
3086	assert!(css.starts_with(":root {\n"));
3087	assert!(css.contains(" --font-mono: \"Quasi Mono\", monospace;\n"));
3088	assert!(css.contains(" --font-sans: \"Quasi Body\", sans-serif;\n"));
3089
3090	// Layer 2 is one hop and no further. A third entry in either stack is
3091	// the shape the standard exists to delete: a chain nobody can predict
3092	// the metrics of, which is what `--font-sans: -apple-system,
3093	// BlinkMacSystemFont, 'Segoe UI', Roboto, ...` was in three apps.
3094	for stack in [FONT_MONO, FONT_SANS] {
3095	assert_eq!(stack.split(',').count(), 2, "{stack} is not one hop");
3096	}
3097
3098	// Two tokens, and no others. `--font-body`, `--font-heading` and
3099	// `--font-display` are gone or out of scope; a token appearing here
3100	// is a fifth answer to a question that has two.
3101	assert_eq!(css.matches("--font-").count(), 2);
3102	}
3103
3104	#[test]
3105	fn every_font_face_names_the_weight_range_because_the_mono_opens_at_200() {
3106	let css = font_face_css("/static/fonts");
3107
3108	assert_eq!(css.matches("@font-face").count(), 2);
3109	assert!(css.contains("src: url(\"/static/fonts/QuasiMono.woff2\") format(\"woff2\");"));
3110	assert!(css.contains("src: url(\"/static/fonts/QuasiBody.woff2\") format(\"woff2\");"));
3111
3112	// The trap. Atkinson Hyperlegible Mono's default instance is
3113	// ExtraLight and the cut keeps the axis, so a `@font-face` that omits
3114	// the range draws the whole UI at 200.
3115	assert_eq!(css.matches("font-weight: 200 800;").count(), 2);
3116
3117	// The families have to be exactly what the tokens ask for, or the
3118	// stack falls through to the generic and the face is dead weight.
3119	for family in [FONT_MONO, FONT_SANS] {
3120	let quoted = family.split(',').next().unwrap();
3121	assert!(css.contains(&format!("font-family: {quoted};")));
3122	}
3123	}
3124
3125	#[test]
3126	fn a_trailing_slash_on_the_base_url_does_not_double_it() {
3127	assert_eq!(font_face_css("fonts/"), font_face_css("fonts"));
3128	assert!(font_face_css("fonts").contains("url(\"fonts/QuasiMono.woff2\")"));
3129	}
3130
3131	// ---- typography, layer 0 ----
3132
3133	/// The live case: MNW's Young Serif, which reached the page through a
3134	/// hand-maintained `@font-face` and a `--font-heading` nothing else knew
3135	/// about.
3136	fn young_serif() -> FontOverride {
3137	FontOverride::new(FontSlot::Display, "\"Young Serif\", serif")
3138	.with_face(FontFace::new("Young Serif", ["ysrf.woff2", "ysrf.ttf"]))
3139	}
3140
3141	#[test]
3142	fn the_house_layer_alone_is_exactly_what_the_free_functions_emit() {
3143	let t = Typography::house("/static/fonts");
3144	assert_eq!(t.font_face_css(), font_face_css("/static/fonts"));
3145	assert_eq!(t.css_vars(), typography_css_vars());
3146	}
3147
3148	#[test]
3149	fn an_unoverridden_display_slot_defines_no_token_at_all() {
3150	// Not "defined empty": undefined, so the consumer's own fallback in
3151	// `var(--font-display, …)` renders. The MNW embeds depend on it.
3152	let t = Typography::house("fonts");
3153	assert!(!t.css_vars().contains("--font-display"));
3154	assert_eq!(t.resolve(FontSlot::Display), None);
3155	assert_eq!(t.css_vars().matches("--font-").count(), 2);
3156	}
3157
3158	#[test]
3159	fn an_override_adds_its_token_and_its_face_without_touching_the_house_two() {
3160	let t = Typography::house("/static/fonts").with_override(young_serif());
3161
3162	assert!(
3163	t.css_vars()
3164	.contains(" --font-display: \"Young Serif\", serif;\n")
3165	);
3166	assert!(
3167	t.css_vars()
3168	.contains(" --font-mono: \"Quasi Mono\", monospace;\n")
3169	);
3170	assert!(
3171	t.css_vars()
3172	.contains(" --font-sans: \"Quasi Body\", sans-serif;\n")
3173	);
3174	assert_eq!(t.resolve(FontSlot::Display), Some("\"Young Serif\", serif"));
3175
3176	let faces = t.font_face_css();
3177	assert_eq!(faces.matches("@font-face").count(), 3);
3178	assert!(faces.contains("font-family: \"Young Serif\";"));
3179	assert!(faces.contains("url(\"/static/fonts/ysrf.woff2\") format(\"woff2\")"));
3180	assert!(faces.contains("url(\"/static/fonts/ysrf.ttf\") format(\"truetype\")"));
3181
3182	// The house faces still come first, so a product face never shadows a
3183	// slot it did not claim.
3184	assert!(faces.find("Quasi Mono").unwrap() < faces.find("Young Serif").unwrap());
3185	}
3186
3187	#[test]
3188	fn overriding_mono_or_sans_replaces_the_house_stack_rather_than_adding_to_it() {
3189	// Nobody wants this today. A layer that only permits overriding the
3190	// slot nobody describes is the exemption restated, not a layer.
3191	let t = Typography::house("fonts").with_override(FontOverride::new(
3192	FontSlot::Mono,
3193	"\"Departure Mono\", monospace",
3194	));
3195
3196	assert!(
3197	t.css_vars()
3198	.contains(" --font-mono: \"Departure Mono\", monospace;\n")
3199	);
3200	assert!(!t.css_vars().contains("Quasi Mono"));
3201	assert_eq!(t.css_vars().matches("--font-").count(), 2);
3202	}
3203
3204	#[test]
3205	#[should_panic(expected = "--font-display is overridden twice")]
3206	fn a_second_override_of_one_slot_is_a_vocabulary_bug_and_says_so() {
3207	let _ = Typography::house("fonts")
3208	.with_override(young_serif())
3209	.with_override(FontOverride::new(FontSlot::Display, "\"Reglo\", serif"));
3210	}
3211
3212	#[test]
3213	fn an_absolute_source_is_taken_as_written_and_a_relative_one_joins_the_base() {
3214	let t = Typography::house("/static/fonts").with_override(
3215	FontOverride::new(FontSlot::Display, "\"Reglo\", serif").with_face(
3216	FontFace::new(
3217	"Reglo",
3218	["Reglo-Bold.woff2", "https://cdn.example/reglo.woff2"],
3219	)
3220	.weight("700"),
3221	),
3222	);
3223	let faces = t.font_face_css();
3224	assert!(faces.contains("url(\"/static/fonts/Reglo-Bold.woff2\")"));
3225	assert!(faces.contains("url(\"https://cdn.example/reglo.woff2\")"));
3226	assert!(faces.contains(" font-weight: 700;\n"));
3227	}
3228
3229	#[test]
3230	fn a_face_loading_renderer_reads_the_family_and_the_source_off_the_layer() {
3231	// The egui case, which has no stylesheet in the path at all: the
3232	// renderer registers the file under a name, and the name has to be
3233	// the one the stack spells or the two halves drift.
3234	let t = Typography::house("fonts").with_override(
3235	FontOverride::new(FontSlot::Display, "\"RecursiveMono\", monospace").with_face(
3236	FontFace::new("RecursiveMono", ["RecursiveMonoLnrSt-Bold.ttf"]).weight("700"),
3237	),
3238	);
3239
3240	let [face] = t.faces(FontSlot::Display) else {
3241	panic!("the display slot ships exactly one face");
3242	};
3243	assert_eq!(face.family(), "RecursiveMono");
3244	assert_eq!(face.sources(), ["RecursiveMonoLnrSt-Bold.ttf"]);
3245	assert!(
3246	t.resolve(FontSlot::Display)
3247	.unwrap()
3248	.contains(face.family())
3249	);
3250	}
3251
3252	#[test]
3253	fn a_source_is_read_back_unresolved_because_only_the_css_wants_a_url() {
3254	let t = Typography::house("/static/fonts").with_override(young_serif());
3255	assert_eq!(
3256	t.faces(FontSlot::Display)[0].sources(),
3257	["ysrf.woff2", "ysrf.ttf"]
3258	);
3259	// The same face, joined to the base, in the sheet.
3260	assert!(
3261	t.font_face_css()
3262	.contains("url(\"/static/fonts/ysrf.woff2\")")
3263	);
3264	}
3265
3266	#[test]
3267	fn a_slot_nobody_overrode_ships_no_faces_including_the_house_two() {
3268	let t = Typography::house("fonts").with_override(young_serif());
3269	assert!(t.faces(FontSlot::Mono).is_empty());
3270	assert!(t.faces(FontSlot::Sans).is_empty());
3271	assert_eq!(t.faces(FontSlot::Display).len(), 1);
3272	}
3273
3274	#[test]
3275	fn an_unrecognised_extension_gets_no_format_hint_rather_than_a_guessed_one() {
3276	let t = Typography::house("fonts").with_override(
3277	FontOverride::new(FontSlot::Display, "\"Odd\", serif")
3278	.with_face(FontFace::new("Odd", ["odd.eot"])),
3279	);
3280	assert!(t.font_face_css().contains("url(\"fonts/odd.eot\");"));
3281	assert!(!t.font_face_css().contains("format(\"eot\")"));
3282	}
3283
3284	#[test]
3285	fn css_puts_the_faces_before_the_tokens_that_name_them() {
3286	let t = Typography::house("fonts").with_override(young_serif());
3287	let css = t.css();
3288	assert!(css.starts_with("@font-face"));
3289	assert!(css.find("@font-face").unwrap() < css.find(":root").unwrap());
3290	}
3291
3292	// ---- loading / fs ----
3293
3294	#[test]
3295	fn load_and_resolve_round_trip() {
3296	let dir = tempfile::tempdir().unwrap();
3297	fs::write(dir.path().join("nord.toml"), nord_toml()).unwrap();
3298	let dirs = vec![(dir.path().to_path_buf(), false)];
3299	let t = load_semantic(&dirs, "nord").unwrap();
3300	assert_eq!(t.meta.name, "Nord");
3301	assert_eq!(t.hex("action"), Some("#81a1c1"));
3302	}
3303
3304	#[test]
3305	fn load_theme_rejects_invalid_id() {
3306	assert!(load_theme(&[], "../evil").is_err());
3307	}
3308
3309	fn meta(id: &str, variant: &str) -> ThemeMeta {
3310	ThemeMeta {
3311	id: id.to_string(),
3312	name: id.to_string(),
3313	variant: variant.to_string(),
3314	is_custom: false,
3315	}
3316	}
3317
3318	fn defaults() -> ThemeDefaults {
3319	ThemeDefaults::new("flatwhite", "nord")
3320	}
3321
3322	// The three the shipped themes actually declare.
3323	#[test]
3324	fn every_shipped_variant_parses() {
3325	assert_eq!(Variant::parse("light"), Some(Variant::Light));
3326	assert_eq!(Variant::parse("dark"), Some(Variant::Dark));
3327	assert_eq!(Variant::parse("high-contrast"), Some(Variant::HighContrast));
3328	assert_eq!(Variant::parse("sepia"), None);
3329	}
3330
3331	// parse_meta already defaults a missing variant to dark, so an
3332	// unrecognized one reading as light would have the crate disagreeing with
3333	// itself. alloy_tui did exactly that before this existed.
3334	#[test]
3335	fn an_unrecognized_variant_reads_the_way_a_missing_one_does() {
3336	assert_eq!(Variant::from("sepia"), Variant::Dark);
3337	assert_eq!(Variant::from(""), Variant::Dark);
3338
3339	let missing: toml::Table = "[meta]\nname = \"X\"\n".parse().unwrap();
3340	assert_eq!(parse_meta("x", &missing, false).kind(), Variant::Dark);
3341	}
3342
3343	#[test]
3344	fn a_selection_round_trips_through_any_store() {
3345	for (stored, expect) in [
3346	(Some("system"), ThemeSelection::Follow),
3347	(None, ThemeSelection::Follow),
3348	(Some(""), ThemeSelection::Follow),
3349	(Some(" "), ThemeSelection::Follow),
3350	(Some("nord"), ThemeSelection::Fixed("nord".into())),
3351	] {
3352	let parsed = ThemeSelection::parse(stored);
3353	assert_eq!(parsed, expect, "{stored:?}");
3354	assert_eq!(
3355	ThemeSelection::parse(Some(parsed.as_str())),
3356	expect,
3357	"what is written reads back as what was meant",
3358	);
3359	}
3360	}
3361
3362	// Nothing saved is follow-the-system, which is what Balanced Breakfast
3363	// expressed as an absent value and GoingsOn as a sentinel. Both are now the
3364	// same thing.
3365	#[test]
3366	fn nothing_chosen_yet_is_follow() {
3367	assert_eq!(ThemeSelection::default(), ThemeSelection::Follow);
3368	}
3369
3370	#[test]
3371	fn a_fixed_selection_wins_when_its_theme_is_installed() {
3372	let available = [meta("nord", "dark"), meta("flatwhite", "light")];
3373	let fixed = ThemeSelection::Fixed("nord".into());
3374	assert_eq!(
3375	fixed.resolve(Variant::Light, &defaults(), &available),
3376	"nord",
3377	"a chosen theme is not overridden by the ambient mode",
3378	);
3379	}
3380
3381	// Themes are deletable in three of the four apps. Handing back an id that
3382	// will fail to load only moves the error somewhere less helpful.
3383	#[test]
3384	fn a_fixed_selection_whose_theme_is_gone_falls_back() {
3385	let available = [meta("nord", "dark"), meta("flatwhite", "light")];
3386	let fixed = ThemeSelection::Fixed("deleted".into());
3387	assert_eq!(
3388	fixed.resolve(Variant::Light, &defaults(), &available),
3389	"flatwhite",
3390	);
3391	}
3392
3393	#[test]
3394	fn follow_picks_the_apps_default_for_the_ambient_mode() {
3395	let available = [meta("nord", "dark"), meta("flatwhite", "light")];
3396	let follow = ThemeSelection::Follow;
3397	assert_eq!(
3398	follow.resolve(Variant::Dark, &defaults(), &available),
3399	"nord",
3400	);
3401	assert_eq!(
3402	follow.resolve(Variant::Light, &defaults(), &available),
3403	"flatwhite",
3404	);
3405	}
3406
3407	// The behaviour Balanced Breakfast could not have: following the system
3408	// into a theme the user installed, when the app's own default is absent.
3409	#[test]
3410	fn follow_uses_any_installed_theme_of_the_right_variant() {
3411	let available = [meta("solarized-light", "light"), meta("mine", "dark")];
3412	assert_eq!(
3413	ThemeSelection::Follow.resolve(Variant::Dark, &defaults(), &available),
3414	"mine",
3415	"the app's `nord` is not installed, but a dark theme is",
3416	);
3417	}
3418
3419	// Always returns something: an app with no theme directory gets the id it
3420	// ships with, and the load error it would have had anyway.
3421	#[test]
3422	fn an_empty_catalog_still_names_the_apps_default() {
3423	assert_eq!(
3424	ThemeSelection::Follow.resolve(Variant::Dark, &defaults(), &[]),
3425	"nord",
3426	);
3427	}
3428
3429	#[test]
3430	fn high_contrast_falls_back_to_dark_unless_named() {
3431	let plain = defaults();
3432	assert_eq!(plain.for_variant(Variant::HighContrast), "nord");
3433
3434	let named = defaults().high_contrast("sharp");
3435	assert_eq!(named.for_variant(Variant::HighContrast), "sharp");
3436	}
3437
3438	// The bug this builder exists to prevent: the Alloy console pushed the
3439	// user's directory first under a comment reading "highest precedence
3440	// first", when both consumers of this vector resolve last-wins. A custom
3441	// theme lost to the packaged one of the same id.
3442	#[test]
3443	fn the_users_own_themes_outrank_everything() {
3444	let root = tempfile::tempdir().unwrap();
3445	let make = \|name: &str\| {
3446	let dir = root.path().join(name);
3447	std::fs::create_dir_all(&dir).unwrap();
3448	dir
3449	};
3450	let (bundled, system, custom) = (make("bundled"), make("system"), make("custom"));
3451
3452	let dirs = ThemeDirs::new()
3453	.custom(Some(custom.clone()))
3454	.bundled(Some(bundled.clone()))
3455	.system(Some(system.clone()))
3456	.build();
3457
3458	assert_eq!(
3459	dirs,
3460	vec![(bundled, false), (system, false), (custom.clone(), true)],
3461	"lowest precedence first, whatever order the tiers were added in",
3462	);
3463	assert!(dirs.last().unwrap().1, "only the user's tier is custom");
3464
3465	// And the ordering means what the consumers think it means.
3466	for dir in dirs.iter().map(\|(dir, _)\| dir) {
3467	std::fs::write(dir.join("shared.toml"), "[meta]\nname = \"x\"\n").unwrap();
3468	}
3469	assert_eq!(
3470	find_theme_path(&dirs, "shared").unwrap().0,
3471	custom.join("shared.toml"),
3472	"the user's copy is the one that loads",
3473	);
3474	}
3475
3476	#[test]
3477	fn a_directory_that_does_not_exist_is_dropped() {
3478	let root = tempfile::tempdir().unwrap();
3479	let real = root.path().join("real");
3480	std::fs::create_dir_all(&real).unwrap();
3481
3482	let dirs = ThemeDirs::new()
3483	.bundled(Some(root.path().join("nope")))
3484	.system(None)
3485	.custom(Some(real.clone()))
3486	.build();
3487
3488	assert_eq!(dirs, vec![(real, true)]);
3489	}
3490
3491	// A Tauri app has two bundled tiers: the resource dir in production and the
3492	// tree build.rs materialized for a dev run with no resource dir.
3493	#[test]
3494	fn more_than_one_bundled_tier_is_allowed() {
3495	let root = tempfile::tempdir().unwrap();
3496	let (first, second) = (root.path().join("a"), root.path().join("b"));
3497	std::fs::create_dir_all(&first).unwrap();
3498	std::fs::create_dir_all(&second).unwrap();
3499
3500	let dirs = ThemeDirs::new()
3501	.bundled(Some(first.clone()))
3502	.bundled(Some(second.clone()))
3503	.build();
3504	assert_eq!(dirs, vec![(first, false), (second, false)]);
3505	}
3506
3507	#[test]
3508	fn list_themes_from_dirs_finds_toml_files() {
3509	let dir = tempfile::tempdir().unwrap();
3510	fs::write(dir.path().join("t.toml"), "[meta]\nname = \"T\"\n").unwrap();
3511	fs::write(dir.path().join("x.txt"), "ignored").unwrap();
3512	let dirs = vec![(dir.path().to_path_buf(), false)];
3513	let themes = list_themes_from_dirs(&dirs);
3514	assert_eq!(themes.len(), 1);
3515	assert_eq!(themes[0].id, "t");
3516	}
3517
3518	#[test]
3519	fn find_theme_path_reverse_priority() {
3520	let d1 = tempfile::tempdir().unwrap();
3521	let d2 = tempfile::tempdir().unwrap();
3522	fs::write(d1.path().join("s.toml"), "[meta]\n").unwrap();
3523	fs::write(d2.path().join("s.toml"), "[meta]\n").unwrap();
3524	let dirs = vec![
3525	(d1.path().to_path_buf(), false),
3526	(d2.path().to_path_buf(), true),
3527	];
3528	let (path, is_custom) = find_theme_path(&dirs, "s").unwrap();
3529	assert!(is_custom);
3530	assert_eq!(path, d2.path().join("s.toml"));
3531	}
3532
3533	#[test]
3534	fn import_theme_valid_and_rejects_empty() {
3535	let src_dir = tempfile::tempdir().unwrap();
3536	let custom_dir = tempfile::tempdir().unwrap();
3537
3538	let good = src_dir.path().join("my-theme.toml");
3539	fs::write(&good, "[surface]\npage = \"#1a1b26\"\n").unwrap();
3540	let meta = import_theme(&good, custom_dir.path()).unwrap();
3541	assert_eq!(meta.id, "my-theme");
3542	assert!(custom_dir.path().join("my-theme.toml").exists());
3543
3544	let empty = src_dir.path().join("empty.toml");
3545	fs::write(&empty, "[meta]\nname = \"E\"\n").unwrap();
3546	assert!(import_theme(&empty, custom_dir.path()).is_err());
3547	}
3548
3549	#[test]
3550	fn import_theme_rejects_invalid_toml() {
3551	let src_dir = tempfile::tempdir().unwrap();
3552	let custom_dir = tempfile::tempdir().unwrap();
3553	let src = src_dir.path().join("bad.toml");
3554	fs::write(&src, "this is not [valid toml [[[").unwrap();
3555	assert!(import_theme(&src, custom_dir.path()).is_err());
3556	}
3557
3558	#[test]
3559	fn delete_theme_removes_and_guards() {
3560	let custom = tempfile::tempdir().unwrap();
3561	let path = custom.path().join("doomed.toml");
3562	fs::write(&path, "[surface]\npage = \"#000\"\n").unwrap();
3563	delete_theme(custom.path(), "doomed").unwrap();
3564	assert!(!path.exists());
3565	assert!(delete_theme(custom.path(), "../etc/passwd").is_err());
3566	assert!(delete_theme(custom.path(), "ghost").is_err());
3567	}
3568
3569	#[test]
3570	fn export_theme_copies_file() {
3571	let src_dir = tempfile::tempdir().unwrap();
3572	let dest_dir = tempfile::tempdir().unwrap();
3573	let content = "[meta]\nname = \"E\"\n[surface]\npage = \"#ffffff\"\n";
3574	fs::write(src_dir.path().join("e.toml"), content).unwrap();
3575	let dirs = vec![(src_dir.path().to_path_buf(), false)];
3576	let dest = dest_dir.path().join("out.toml");
3577	export_theme(&dirs, "e", &dest).unwrap();
3578	assert_eq!(fs::read_to_string(&dest).unwrap(), content);
3579	assert!(export_theme(&dirs, "missing", &dest).is_err());
3580	}
3581
3582	#[test]
3583	fn load_theme_preview_returns_role_swatches() {
3584	let dir = tempfile::tempdir().unwrap();
3585	fs::write(dir.path().join("nord.toml"), nord_toml()).unwrap();
3586	let dirs = vec![(dir.path().to_path_buf(), false)];
3587	let p = load_theme_preview(&dirs, "nord").unwrap();
3588	assert_eq!(p.background.as_deref(), Some("#2e3440")); // surface.page
3589	assert_eq!(p.foreground.as_deref(), Some("#d8dee9")); // content.primary
3590	assert_eq!(p.accent.as_deref(), Some("#81a1c1")); // action.primary
3591	assert_eq!(p.border.as_deref(), Some("#4c566a")); // line.border
3592	}
3593
3594	#[test]
3595	fn bundled_themes_dir_resolves_to_shipped_themes() {
3596	// The crate ships its themes, so this must resolve in-tree and the
3597	// Akari defaults the console falls back to must be present.
3598	let dir = bundled_themes_dir().expect("makeover ships a themes/ directory");
3599	assert!(dir.join("akari-dawn.toml").is_file());
3600	assert!(dir.join("akari-night.toml").is_file());
3601	}
3602
3603	#[test]
3604	fn every_theme_is_accounted_for_in_third_party_notices() {
3605	// Attribution is a redistribution obligation, not a nicety: adding a
3606	// theme without a notice entry silently ships someone's work
3607	// uncredited. Fail here instead.
3608	let notices = std::fs::read_to_string(
3609	Path::new(env!("CARGO_MANIFEST_DIR")).join("THIRD-PARTY-NOTICES.md"),
3610	)
3611	.expect("THIRD-PARTY-NOTICES.md must exist");
3612	let missing: Vec<&str> = embedded_themes()
3613	.map(\|(id, _)\| id)
3614	.filter(\|id\| !notices.contains(*id))
3615	.collect();
3616	assert!(
3617	missing.is_empty(),
3618	"themes missing from THIRD-PARTY-NOTICES.md: {missing:?}"
3619	);
3620	}
3621
3622	#[test]
3623	fn adapted_themes_carry_inline_attribution() {
3624	// Each adapted file must name its upstream in-file, so the credit
3625	// survives someone copying a single .toml out of the crate.
3626	const ORIGINALS: [&str; 5] = [
3627	"makenotwork",
3628	"goingson",
3629	"audiofiles",
3630	"high-contrast",
3631	"neobrute",
3632	];
3633	for (id, source) in embedded_themes() {
3634	if ORIGINALS.contains(&id) {
3635	continue;
3636	}
3637	assert!(
3638	source.contains("adapted from"),
3639	"adapted theme `{id}` is missing its inline attribution header"
3640	);
3641	}
3642	}
3643
3644	#[test]
3645	fn embedded_themes_match_the_directory() {
3646	// The embedded copy and themes/ are two views of one source. If they
3647	// ever disagree, path-based and path-free consumers render different
3648	// theme sets, which is exactly the drift shipping the data was meant
3649	// to prevent.
3650	let dir = bundled_themes_dir().unwrap();
3651	let mut on_disk: Vec<String> = std::fs::read_dir(&dir)
3652	.unwrap()
3653	.filter_map(\|e\| {
3654	let path = e.ok()?.path();
3655	if path.extension()? != "toml" {
3656	return None;
3657	}
3658	Some(path.file_stem()?.to_str()?.to_string())
3659	})
3660	.collect();
3661	let mut embedded: Vec<String> = embedded_themes().map(\|(id, _)\| id.to_string()).collect();
3662	on_disk.sort();
3663	embedded.sort();
3664	assert_eq!(embedded, on_disk, "embedded theme set drifted from themes/");
3665	}
3666
3667	#[test]
3668	fn every_embedded_theme_parses() {
3669	// Guards the path-free consumers (MNW server, the Tauri build steps)
3670	// the same way every_shipped_theme_loads guards the path-based ones.
3671	let mut count = 0;
3672	for (id, source) in embedded_themes() {
3673	parse_theme_str(id, source, false)
3674	.unwrap_or_else(\|e\| panic!("embedded theme `{id}` failed to parse: {e}"));
3675	count += 1;
3676	}
3677	assert!(count >= 30, "expected the full theme set, got {count}");
3678	}
3679
3680	#[test]
3681	fn every_shipped_theme_loads() {
3682	// Guards the data, not just the loader: a malformed or truncated
3683	// .toml in themes/ is a shipping bug, and it should fail here rather
3684	// than at a user's first launch.
3685	let dir = bundled_themes_dir().unwrap();
3686	let dirs = vec![(dir.clone(), false)];
3687	let themes = list_themes_from_dirs(&dirs);
3688	assert!(
3689	themes.len() >= 30,
3690	"expected the full theme set, got {}",
3691	themes.len()
3692	);
3693	for meta in &themes {
3694	load_theme(&dirs, &meta.id)
3695	.unwrap_or_else(\|e\| panic!("shipped theme `{}` failed to load: {e}", meta.id));
3696	}
3697	}
3698	}
3699