max / makeover

137.4 KB · 3614 lines History Blame Raw

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.
1102	// ============================================================================
1103
1104	/// A slot in the house font vocabulary — the unit an override replaces.
1105	///
1106	/// Three, and the third is deliberately empty by default: `display` is the
1107	/// brand tier, it has no house answer, and a product that does not override it
1108	/// leaves the token undefined so whatever the consumer wrote as a fallback
1109	/// renders. The MNW embeds rely on exactly that.
1110	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
1111	pub enum FontSlot {
1112	/// Code, data, identifiers, cell grids. [`FONT_MONO`] by default.
1113	Mono,
1114	/// Body and UI text: everything that is not mono or brand. [`FONT_SANS`].
1115	Sans,
1116	/// The brand / display tier. No house default, per `cdf8ac09`.
1117	Display,
1118	}
1119
1120	impl FontSlot {
1121	/// Every slot, in the order they are emitted.
1122	pub const ALL: [FontSlot; 3] = [FontSlot::Mono, FontSlot::Sans, FontSlot::Display];
1123
1124	/// The custom property this slot is read through.
1125	pub fn token(self) -> &'static str {
1126	match self {
1127	FontSlot::Mono => "--font-mono",
1128	FontSlot::Sans => "--font-sans",
1129	FontSlot::Display => "--font-display",
1130	}
1131	}
1132
1133	/// The house stack, or `None` for the brand tier.
1134	pub fn house_default(self) -> Option<&'static str> {
1135	match self {
1136	FontSlot::Mono => Some(FONT_MONO),
1137	FontSlot::Sans => Some(FONT_SANS),
1138	FontSlot::Display => None,
1139	}
1140	}
1141	}
1142
1143	/// One `@font-face` an override brings with it.
1144	///
1145	/// A product overriding a slot usually has to ship the face too, and the two
1146	/// halves have to agree on a family name. Declaring them together is what
1147	/// makes that agreement structural rather than a string typed twice.
1148	#[derive(Debug, Clone)]
1149	pub struct FontFace {
1150	family: String,
1151	sources: Vec<String>,
1152	weight: Option<String>,
1153	style: Option<String>,
1154	}
1155
1156	impl FontFace {
1157	/// A face named `family`, fetched from `sources`.
1158	///
1159	/// Each source is either a bare filename, resolved against the
1160	/// [`Typography`] base URL, or an absolute one (`/…` or `https://…`) taken
1161	/// as written. The `format()` hint is inferred from the extension —
1162	/// `woff2`, `woff`, `ttf`, `otf` — and omitted for anything else rather
1163	/// than guessed, since a wrong hint is worse than none.
1164	pub fn new<S: Into<String>>(
1165	family: impl Into<String>,
1166	sources: impl IntoIterator<Item = S>,
1167	) -> Self {
1168	Self {
1169	family: family.into(),
1170	sources: sources.into_iter().map(Into::into).collect(),
1171	weight: None,
1172	style: None,
1173	}
1174	}
1175
1176	/// `font-weight`, as CSS writes it: `"700"`, or `"200 800"` for a variable
1177	/// axis. Omitted when unset, which means `normal`.
1178	///
1179	/// A variable face MUST name its range here for the same reason the house
1180	/// faces do: a `@font-face` with no range makes the browser resolve every
1181	/// weight to the file's default instance.
1182	#[must_use]
1183	pub fn weight(mut self, weight: impl Into<String>) -> Self {
1184	self.weight = Some(weight.into());
1185	self
1186	}
1187
1188	/// `font-style`. Omitted when unset, which means `normal`.
1189	#[must_use]
1190	pub fn style(mut self, style: impl Into<String>) -> Self {
1191	self.style = Some(style.into());
1192	self
1193	}
1194
1195	fn css(&self, base: &str) -> String {
1196	use std::fmt::Write as _;
1197
1198	let src = self
1199	.sources
1200	.iter()
1201	.map(\|s\| {
1202	let url = if s.starts_with('/') \|\| s.contains("://") {
1203	s.clone()
1204	} else {
1205	format!("{base}/{s}")
1206	};
1207	match font_format(s) {
1208	Some(fmt) => format!("url(\"{url}\") format(\"{fmt}\")"),
1209	None => format!("url(\"{url}\")"),
1210	}
1211	})
1212	.collect::<Vec<_>>()
1213	.join(",\n ");
1214
1215	let mut out = format!(
1216	"@font-face {{\n font-family: \"{}\";\n src: {src};\n",
1217	self.family
1218	);
1219	if let Some(w) = &self.weight {
1220	let _ = writeln!(out, " font-weight: {w};");
1221	}
1222	if let Some(s) = &self.style {
1223	let _ = writeln!(out, " font-style: {s};");
1224	}
1225	out.push_str(" font-display: swap;\n}\n\n");
1226	out
1227	}
1228	}
1229
1230	/// The `format()` hint for a source, by extension. `None` when unrecognised.
1231	fn font_format(source: &str) -> Option<&'static str> {
1232	match source.rsplit('.').next()?.to_ascii_lowercase().as_str() {
1233	"woff2" => Some("woff2"),
1234	"woff" => Some("woff"),
1235	"ttf" => Some("truetype"),
1236	"otf" => Some("opentype"),
1237	_ => None,
1238	}
1239	}
1240
1241	/// One product's answer for one slot: the stack, and any faces it ships.
1242	#[derive(Debug, Clone)]
1243	pub struct FontOverride {
1244	slot: FontSlot,
1245	stack: String,
1246	faces: Vec<FontFace>,
1247	}
1248
1249	impl FontOverride {
1250	/// Point `slot` at `stack`.
1251	///
1252	/// `stack` is the CSS value the token takes, written the way the house
1253	/// stacks are: the family, then one hop to a system generic. Layer 2 is
1254	/// still one hop and no further — an override is a different answer to the
1255	/// slot, not a licence to write the fallback chain the standard deleted.
1256	pub fn new(slot: FontSlot, stack: impl Into<String>) -> Self {
1257	Self {
1258	slot,
1259	stack: stack.into(),
1260	faces: Vec::new(),
1261	}
1262	}
1263
1264	/// Ship a face with the override.
1265	#[must_use]
1266	pub fn with_face(mut self, face: FontFace) -> Self {
1267	self.faces.push(face);
1268	self
1269	}
1270
1271	/// The slot this answers.
1272	pub fn slot(&self) -> FontSlot {
1273	self.slot
1274	}
1275
1276	/// The stack it resolves to.
1277	pub fn stack(&self) -> &str {
1278	&self.stack
1279	}
1280	}
1281
1282	/// The whole typography layer for one product: the house defaults, plus
1283	/// whatever it overrides.
1284	///
1285	/// This is what a build script composes and what
1286	/// `makeover_build::typography_css_from` writes. [`typography_css_vars`] and
1287	/// [`font_face_css`] are the no-override case of it and stay for callers that
1288	/// have nothing to declare.
1289	#[derive(Debug, Clone)]
1290	pub struct Typography {
1291	base_url: String,
1292	overrides: Vec<FontOverride>,
1293	}
1294
1295	impl Typography {
1296	/// The house layer alone, fetching faces from `base_url` — the directory
1297	/// the consumer serves fonts from, with or without a trailing slash.
1298	pub fn house(base_url: impl Into<String>) -> Self {
1299	Self {
1300	base_url: base_url.into(),
1301	overrides: Vec::new(),
1302	}
1303	}
1304
1305	/// Add one product override.
1306	///
1307	/// # Panics
1308	///
1309	/// If the slot is already overridden. One declaration per product per
1310	/// slot: a second is not a merge to resolve, it is two answers to a
1311	/// question that has one, and the vocabulary is what wants fixing.
1312	#[must_use]
1313	pub fn with_override(mut self, ov: FontOverride) -> Self {
1314	assert!(
1315	!self.overrides.iter().any(\|o\| o.slot == ov.slot),
1316	"{} is overridden twice; one declaration per product per slot",
1317	ov.slot.token()
1318	);
1319	self.overrides.push(ov);
1320	self
1321	}
1322
1323	/// What `slot` resolves to under this layer, or `None` for a brand slot
1324	/// nobody overrode.
1325	///
1326	/// The resolution, for a renderer that has a face to choose rather than a
1327	/// stylesheet to emit.
1328	pub fn resolve(&self, slot: FontSlot) -> Option<&str> {
1329	self.overrides
1330	.iter()
1331	.find(\|o\| o.slot == slot)
1332	.map(\|o\| o.stack.as_str())
1333	.or_else(\|\| slot.house_default())
1334	}
1335
1336	/// The `@font-face` rules: the two house faces, then each override's.
1337	pub fn font_face_css(&self) -> String {
1338	let base = self.base_url.trim_end_matches('/');
1339	let mut out = font_face_css(base);
1340	for ov in &self.overrides {
1341	for face in &ov.faces {
1342	out.push_str(&face.css(base));
1343	}
1344	}
1345	out
1346	}
1347
1348	/// The resolved tokens as CSS declarations, no selector.
1349	pub fn css_declarations(&self) -> String {
1350	use std::fmt::Write as _;
1351
1352	let mut out = String::new();
1353	for slot in FontSlot::ALL {
1354	if let Some(stack) = self.resolve(slot) {
1355	let _ = writeln!(out, " {}: {stack};", slot.token());
1356	}
1357	}
1358	out
1359	}
1360
1361	/// The resolved tokens as a `:root { … }` block.
1362	pub fn css_vars(&self) -> String {
1363	format!(":root {{\n{}}}\n", self.css_declarations())
1364	}
1365
1366	/// Faces then tokens, in the order a stylesheet wants them.
1367	pub fn css(&self) -> String {
1368	format!("{}{}", self.font_face_css(), self.css_vars())
1369	}
1370	}
1371
1372	// ============================================================================
1373	// Loading / parsing
1374	// ============================================================================
1375
1376	/// Validate a theme ID contains only safe characters (alphanumeric, hyphens, underscores).
1377	pub fn validate_theme_id(id: &str) -> Result<(), String> {
1378	if !id
1379	.chars()
1380	.all(\|c\| c.is_alphanumeric() \|\| c == '-' \|\| c == '_')
1381	{
1382	return Err(format!("Invalid theme ID: {id}"));
1383	}
1384	Ok(())
1385	}
1386
1387	/// Parse the `[meta]` section into `ThemeMeta`.
1388	///
1389	/// Falls back to the file ID as the name and `"dark"` as the variant.
1390	pub fn parse_meta(id: &str, table: &toml::Table, is_custom: bool) -> ThemeMeta {
1391	let meta = table.get("meta").and_then(\|m\| m.as_table());
1392	let name = meta
1393	.and_then(\|m\| m.get("name"))
1394	.and_then(\|v\| v.as_str())
1395	.unwrap_or(id)
1396	.to_string();
1397	let variant = meta
1398	.and_then(\|m\| m.get("variant"))
1399	.and_then(\|v\| v.as_str())
1400	.unwrap_or("dark")
1401	.to_string();
1402
1403	ThemeMeta {
1404	id: id.to_string(),
1405	name,
1406	variant,
1407	is_custom,
1408	}
1409	}
1410
1411	// ============================================================================
1412	// Choosing a theme.
1413	//
1414	// The file half of this crate was always shared; the selection half was not,
1415	// and four apps re-rolled it four ways. GoingsOn stores a "system" sentinel in
1416	// localStorage, Balanced Breakfast treats an absent value as follow-the-system
1417	// and hardcodes two theme ids as its light/dark pair, audiofiles keeps the id
1418	// in a synced SQLite table, and the Alloy console parses COLORFGBG. They also
1419	// disagreed about what a variant string means: this crate defaults a missing
1420	// one to "dark" while alloy_tui parsed an unrecognized one as light.
1421	//
1422	// What cannot be shared is the store — localStorage, a synced config table and
1423	// a TOML file are genuinely different places. What can be shared, and is here,
1424	// is the meaning: one vocabulary for variants, one encoding for "what did the
1425	// user choose", and one rule for turning that into an id that exists.
1426	// ============================================================================
1427
1428	/// A theme's kind, as declared by `meta.variant`.
1429	///
1430	/// Three, not two: one shipped theme is `high-contrast`, and an app that
1431	/// matched on light-or-dark alone would quietly file it under the wrong one.
1432	#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize)]
1433	#[serde(rename_all = "kebab-case")]
1434	pub enum Variant {
1435	Light,
1436	Dark,
1437	HighContrast,
1438	}
1439
1440	impl Variant {
1441	/// The spelling used in a theme file and in [`ThemeMeta::variant`].
1442	#[must_use]
1443	pub const fn as_str(self) -> &'static str {
1444	match self {
1445	Variant::Light => "light",
1446	Variant::Dark => "dark",
1447	Variant::HighContrast => "high-contrast",
1448	}
1449	}
1450
1451	/// Read a variant string, or `None` if it names none of them.
1452	#[must_use]
1453	pub fn parse(raw: &str) -> Option<Self> {
1454	match raw {
1455	"light" => Some(Variant::Light),
1456	"dark" => Some(Variant::Dark),
1457	"high-contrast" => Some(Variant::HighContrast),
1458	_ => None,
1459	}
1460	}
1461	}
1462
1463	impl std::fmt::Display for Variant {
1464	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1465	f.write_str(self.as_str())
1466	}
1467	}
1468
1469	/// Anything unrecognized reads as dark, which is what [`parse_meta`] already
1470	/// does with a missing one. Consumers that guessed light for an unknown string
1471	/// were disagreeing with the crate that produced it.
1472	impl From<&str> for Variant {
1473	fn from(raw: &str) -> Self {
1474	Variant::parse(raw).unwrap_or(Variant::Dark)
1475	}
1476	}
1477
1478	impl ThemeMeta {
1479	/// This theme's variant as a value rather than a string.
1480	#[must_use]
1481	pub fn kind(&self) -> Variant {
1482	Variant::from(self.variant.as_str())
1483	}
1484	}
1485
1486	/// The spelling of "follow whatever the system is doing", in every store.
1487	pub const FOLLOW: &str = "system";
1488
1489	/// What the user chose, as opposed to what is being rendered.
1490	///
1491	/// The distinction is the whole point: `Follow` is a standing instruction that
1492	/// resolves differently as the ambient mode changes, and a `Fixed` id is an
1493	/// answer that does not. An app that stored only the rendered id could not tell
1494	/// the two apart the next time the system flipped to dark.
1495	#[derive(Debug, Clone, PartialEq, Eq, Default)]
1496	pub enum ThemeSelection {
1497	/// Track the ambient light/dark mode.
1498	#[default]
1499	Follow,
1500	/// Always this theme.
1501	Fixed(String),
1502	}
1503
1504	impl ThemeSelection {
1505	/// Read a stored selection. An empty or absent value is [`Follow`], which
1506	/// is what an app with nothing saved yet should do.
1507	///
1508	/// [`Follow`]: ThemeSelection::Follow
1509	#[must_use]
1510	pub fn parse(raw: Option<&str>) -> Self {
1511	match raw.map(str::trim) {
1512	None \| Some("" \| FOLLOW) => ThemeSelection::Follow,
1513	Some(id) => ThemeSelection::Fixed(id.to_string()),
1514	}
1515	}
1516
1517	/// The string to persist, whatever the store is.
1518	#[must_use]
1519	pub fn as_str(&self) -> &str {
1520	match self {
1521	ThemeSelection::Follow => FOLLOW,
1522	ThemeSelection::Fixed(id) => id,
1523	}
1524	}
1525
1526	/// Turn a selection into a theme id that exists.
1527	///
1528	/// `ambient` is the light/dark mode the app learned however it can: a
1529	/// `prefers-color-scheme` media query, an OS appearance API, `COLORFGBG`
1530	/// from a terminal. `available` is what [`list_themes_from_dirs`] found.
1531	///
1532	/// A `Fixed` id that is no longer on disk falls through to the same path as
1533	/// `Follow` rather than being returned anyway. Themes are deletable in
1534	/// three of the four apps, and handing back an id that will fail to load
1535	/// only moves the error somewhere less helpful.
1536	///
1537	/// The fallback chain is: the app's own default for the ambient mode if it
1538	/// is installed, then any installed theme of that variant, then the app's
1539	/// default regardless. The last step means this always returns something,
1540	/// and an app with no theme directory at all gets the id it ships with and
1541	/// the load error it would have had anyway.
1542	#[must_use]
1543	pub fn resolve(
1544	&self,
1545	ambient: Variant,
1546	defaults: &ThemeDefaults,
1547	available: &[ThemeMeta],
1548	) -> String {
1549	let installed = \|id: &str\| available.iter().any(\|meta\| meta.id == id);
1550
1551	if let ThemeSelection::Fixed(id) = self
1552	&& installed(id)
1553	{
1554	return id.clone();
1555	}
1556
1557	let preferred = defaults.for_variant(ambient);
1558	if installed(preferred) {
1559	return preferred.to_string();
1560	}
1561	available
1562	.iter()
1563	.find(\|meta\| meta.kind() == ambient)
1564	.map_or_else(\|\| preferred.to_string(), \|meta\| meta.id.clone())
1565	}
1566	}
1567
1568	impl std::fmt::Display for ThemeSelection {
1569	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
1570	f.write_str(self.as_str())
1571	}
1572	}
1573
1574	/// The themes an app falls back to, one per ambient mode.
1575	///
1576	/// App-specific on purpose: which theme is "the app's own" is the app's
1577	/// identity, not this crate's business. What is shared is everything around it.
1578	#[derive(Debug, Clone)]
1579	pub struct ThemeDefaults {
1580	light: String,
1581	dark: String,
1582	high_contrast: Option<String>,
1583	}
1584
1585	impl ThemeDefaults {
1586	pub fn new(light: impl Into<String>, dark: impl Into<String>) -> Self {
1587	Self {
1588	light: light.into(),
1589	dark: dark.into(),
1590	high_contrast: None,
1591	}
1592	}
1593
1594	/// Name a theme for a high-contrast ambient mode. Without one, that mode
1595	/// falls back to the dark default, which is the safer of the two to read.
1596	#[must_use]
1597	pub fn high_contrast(mut self, id: impl Into<String>) -> Self {
1598	self.high_contrast = Some(id.into());
1599	self
1600	}
1601
1602	#[must_use]
1603	pub fn for_variant(&self, variant: Variant) -> &str {
1604	match variant {
1605	Variant::Light => &self.light,
1606	Variant::Dark => &self.dark,
1607	Variant::HighContrast => self.high_contrast.as_ref().unwrap_or(&self.dark),
1608	}
1609	}
1610	}
1611
1612	// ============================================================================
1613	// Where themes are looked for.
1614	//
1615	// Four apps built this vector by hand, two of them byte-for-byte identically,
1616	// and one of them built it backwards: the Alloy console pushed the user's own
1617	// directory first, under a comment saying "highest precedence first", when both
1618	// consumers of the vector resolve last wins. A user's custom theme lost to
1619	// the packaged one of the same id.
1620	//
1621	// Hence a builder that names the tiers rather than a function taking a vector.
1622	// The precedence is stated once, here, and a caller cannot express it backwards
1623	// because the order is not theirs to choose.
1624	// ============================================================================
1625
1626	/// Builds the search path [`load_theme`] and [`list_themes_from_dirs`] take.
1627	///
1628	/// Tiers are added in whatever order is convenient and always end up in
1629	/// precedence order: the user's own themes win, then whatever the system
1630	/// ships, then whatever the app bundles.
1631	///
1632	/// A directory that does not exist is dropped rather than carried, so callers
1633	/// can offer every tier they might have without checking each one.
1634	#[derive(Debug, Default, Clone)]
1635	pub struct ThemeDirs {
1636	bundled: Vec<PathBuf>,
1637	system: Vec<PathBuf>,
1638	custom: Option<PathBuf>,
1639	}
1640
1641	impl ThemeDirs {
1642	#[must_use]
1643	pub fn new() -> Self {
1644	Self::default()
1645	}
1646
1647	/// Themes the app ships with. Lowest precedence.
1648	///
1649	/// Takes more than one because a Tauri app has two: the bundled resource
1650	/// directory in production, and the tree `build.rs` materialized for a
1651	/// `cargo run` that has no resource directory at all.
1652	#[must_use]
1653	pub fn bundled(mut self, dir: Option<PathBuf>) -> Self {
1654	self.bundled.extend(dir);
1655	self
1656	}
1657
1658	/// Themes the machine ships, from an image or a package. Overrides bundled.
1659	#[must_use]
1660	pub fn system(mut self, dir: Option<PathBuf>) -> Self {
1661	self.system.extend(dir);
1662	self
1663	}
1664
1665	/// The user's own themes. Highest precedence, and the only tier flagged
1666	/// custom, which is what makes them exportable and deletable.
1667	#[must_use]
1668	pub fn custom(mut self, dir: Option<PathBuf>) -> Self {
1669	self.custom = dir;
1670	self
1671	}
1672
1673	/// The search path, lowest precedence first.
1674	#[must_use]
1675	pub fn build(self) -> Vec<(PathBuf, bool)> {
1676	let mut dirs = Vec::new();
1677	for dir in self.bundled.into_iter().chain(self.system) {
1678	if dir.is_dir() {
1679	dirs.push((dir, false));
1680	}
1681	}
1682	if let Some(dir) = self.custom
1683	&& dir.is_dir()
1684	{
1685	dirs.push((dir, true));
1686	}
1687	dirs
1688	}
1689	}
1690
1691	/// Extract the intent color sections into a flat `HashMap` with dotted keys
1692	/// like `"surface.page"`, `"status.danger"`, `"category.one"`.
1693	///
1694	/// The tonal steps of `content.primary` are filled in here rather than read, by
1695	/// [`derive_tonal_steps`]. Anything a theme authored under those keys is
1696	/// replaced.
1697	pub fn extract_colors(table: &toml::Table) -> HashMap<String, String> {
1698	let mut colors = HashMap::new();
1699	for section in COLOR_SECTIONS {
1700	if let Some(sect) = table.get(*section).and_then(\|s\| s.as_table()) {
1701	for (key, val) in sect {
1702	if let Some(color) = val.as_str() {
1703	colors.insert(format!("{section}.{key}"), color.to_string());
1704	}
1705	}
1706	}
1707	}
1708	derive_tonal_steps(&mut colors);
1709	colors
1710	}
1711
1712	/// Fill in the tonal steps of `content.primary`, overwriting whatever the theme
1713	/// authored under those keys.
1714	///
1715	/// # Why they are not authored
1716	///
1717	/// `content.secondary` and `content.muted` are not independent colours. They are
1718	/// the ink, one step and two steps back, and a theme that names them separately
1719	/// is stating three times something it stated once — which is how three of the
1720	/// bundled themes came to author a `secondary` lighter than their own
1721	/// `primary` (nord, solarized-dark) or identical to it (dracula), inverting the
1722	/// emphasis ramp the whole vocabulary rests on. Deriving them makes
1723	/// `content` > `content-secondary` > `content-muted` true by construction in
1724	/// every theme, including one a user writes.
1725	///
1726	/// Applied at load rather than in [`resolve`] so that there is one answer: the
1727	/// resolved token layer, the ANSI table ([`ansi_intent`] reads authored keys),
1728	/// and every consumer holding a [`ThemeColors`] all see the same value. A
1729	/// derivation visible from only one of those is how a terminal and a webview
1730	/// come to disagree about what muted means.
1731	///
1732	/// Both keys need `content.primary` and `surface.page` to exist and parse. When
1733	/// either is missing the step is skipped and anything authored is left where it
1734	/// is, mirroring the skip-missing behaviour of the rest of the crate — a
1735	/// half-written theme keeps whatever it has rather than losing it.
1736	///
1737	/// # The ratio is a starting point, not the answer
1738	///
1739	/// Each step is pushed further toward the page until it clears [`STEP_FLOOR`]
1740	/// against the ink, so what the theme gets is a step that can be seen rather
1741	/// than a step of the agreed size. The two are the same number in every bundled
1742	/// theme but the two with a pure-black ink, where the ratio has no range to
1743	/// travel in and the nominal step lands 3/255 from where it started.
1744	pub fn derive_tonal_steps<S: std::hash::BuildHasher>(colors: &mut HashMap<String, String, S>) {
1745	let ink = colors.get("content.primary").and_then(\|v\| Rgb::from_hex(v));
1746	let page = colors.get("surface.page").and_then(\|v\| Rgb::from_hex(v));
1747	let (Some(ink), Some(page)) = (ink, page) else {
1748	return;
1749	};
1750	// Each step starts no nearer than the one before it landed, so pushing
1751	// secondary out cannot carry it past muted and invert the ramp.
1752	let mut reached = 0.0;
1753	for (key, step) in [
1754	("content.secondary", Emphasis::Secondary),
1755	("content.muted", Emphasis::Muted),
1756	] {
1757	let (color, ratio) = step_clearing_floor(ink, page, step.ratio().max(reached));
1758	reached = ratio;
1759	colors.insert(key.to_string(), color.to_hex());
1760	}
1761	}
1762
1763	/// The step `from` of the way from `ink` to `page`, pushed toward `page` until
1764	/// it clears [`STEP_FLOOR`] against the ink it is a step of. Returns the colour
1765	/// and the ratio it was found at.
1766	///
1767	/// A forward scan rather than a solve, because it wants the first ratio that
1768	/// clears: contrast against the base rises with the distance travelled, but it
1769	/// rises through sRGB's transfer curve and OKLab's chroma path, and a bisection
1770	/// would trust a monotonicity nothing here guarantees.
1771	///
1772	/// Travel stops at the ground. A theme whose ink and page are the same colour
1773	/// has no step to take, and the ground is the honest answer — nothing past it
1774	/// is a step of the ink any more.
1775	fn step_clearing_floor(ink: Rgb, page: Rgb, from: f32) -> (Rgb, f32) {
1776	// Finer than 8-bit sRGB can resolve on the shortest ramp in the corpus, so
1777	// the scan never steps over the first colour that clears.
1778	const PROBE: f32 = 0.005;
1779	let mut ratio = from.clamp(0.0, 1.0);
1780	loop {
1781	let color = tonal(ink, page, ratio);
1782	if wcag_contrast(color, ink) >= STEP_FLOOR \|\| ratio >= 1.0 {
1783	return (color, ratio);
1784	}
1785	ratio = (ratio + PROBE).min(1.0);
1786	}
1787	}
1788
1789	/// Scan directories for `.toml` theme files and return metadata for each.
1790	///
1791	/// Directories are checked in order; later entries override earlier ones by ID.
1792	/// Each entry in `dirs` is `(path, is_custom)`.
1793	pub fn list_themes_from_dirs(dirs: &[(PathBuf, bool)]) -> Vec<ThemeMeta> {
1794	let mut seen: HashMap<String, ThemeMeta> = HashMap::new();
1795
1796	for (dir, is_custom) in dirs {
1797	let Ok(entries) = std::fs::read_dir(dir) else {
1798	continue;
1799	};
1800
1801	for entry in entries {
1802	let Ok(entry) = entry else {
1803	continue;
1804	};
1805	let path = entry.path();
1806	if path.extension().and_then(\|e\| e.to_str()) != Some("toml") {
1807	continue;
1808	}
1809
1810	let id = path
1811	.file_stem()
1812	.and_then(\|s\| s.to_str())
1813	.unwrap_or_default()
1814	.to_string();
1815
1816	let Ok(content) = std::fs::read_to_string(&path) else {
1817	continue;
1818	};
1819	let table: toml::Table = match content.parse() {
1820	Ok(t) => t,
1821	Err(_) => continue,
1822	};
1823
1824	seen.insert(id.clone(), parse_meta(&id, &table, *is_custom));
1825	}
1826	}
1827
1828	let mut themes: Vec<ThemeMeta> = seen.into_values().collect();
1829	themes.sort_by(\|a, b\| a.name.cmp(&b.name));
1830	themes
1831	}
1832
1833	/// Find a theme file by ID in the given directories.
1834	///
1835	/// Checks directories in reverse order so the highest-priority directory wins.
1836	/// Returns `(path, is_custom)` or `None` if not found.
1837	pub fn find_theme_path(dirs: &[(PathBuf, bool)], id: &str) -> Option<(PathBuf, bool)> {
1838	let filename = format!("{id}.toml");
1839
1840	for (dir, is_custom) in dirs.iter().rev() {
1841	let path = dir.join(&filename);
1842	if path.is_file() {
1843	return Some((path, *is_custom));
1844	}
1845	}
1846
1847	None
1848	}
1849
1850	/// Parse a complete theme (metadata + colors) from raw TOML content, with no
1851	/// filesystem access. For callers that embed themes at compile time.
1852	pub fn parse_theme_str(id: &str, content: &str, is_custom: bool) -> Result<ThemeColors, String> {
1853	validate_theme_id(id)?;
1854	let table: toml::Table = content
1855	.parse()
1856	.map_err(\|e\| format!("Failed to parse theme '{id}': {e}"))?;
1857	let meta = parse_meta(id, &table, is_custom);
1858	let colors = extract_colors(&table);
1859	Ok(ThemeColors { meta, colors })
1860	}
1861
1862	/// Load a complete theme (metadata + colors) by ID from the given directories.
1863	pub fn load_theme(dirs: &[(PathBuf, bool)], id: &str) -> Result<ThemeColors, String> {
1864	validate_theme_id(id)?;
1865
1866	let (path, is_custom) =
1867	find_theme_path(dirs, id).ok_or_else(\|\| format!("Theme '{id}' not found"))?;
1868
1869	let content = std::fs::read_to_string(&path)
1870	.map_err(\|e\| format!("Failed to read {}: {}", path.display(), e))?;
1871
1872	let table: toml::Table = content
1873	.parse()
1874	.map_err(\|e\| format!("Failed to parse {}: {}", path.display(), e))?;
1875
1876	let meta = parse_meta(id, &table, is_custom);
1877	let colors = extract_colors(&table);
1878
1879	Ok(ThemeColors { meta, colors })
1880	}
1881
1882	/// Load a theme and resolve it to the full intent token set in one step.
1883	pub fn load_semantic(dirs: &[(PathBuf, bool)], id: &str) -> Result<SemanticTokens, String> {
1884	Ok(resolve(&load_theme(dirs, id)?))
1885	}
1886
1887	/// Import a theme TOML file into the custom themes directory.
1888	///
1889	/// Validates that the file is parseable TOML with at least one intent color
1890	/// section, then copies it to `custom_dir/{id}.toml`. Returns the theme metadata.
1891	pub fn import_theme(source_path: &Path, custom_dir: &Path) -> Result<ThemeMeta, String> {
1892	let content = std::fs::read_to_string(source_path)
1893	.map_err(\|e\| format!("Failed to read {}: {}", source_path.display(), e))?;
1894
1895	let table: toml::Table = content.parse().map_err(\|e\| format!("Invalid TOML: {e}"))?;
1896
1897	let has_colors = COLOR_SECTIONS
1898	.iter()
1899	.any(\|s\| table.get(*s).and_then(\|v\| v.as_table()).is_some());
1900	if !has_colors {
1901	return Err(format!(
1902	"Theme file must have at least one color section ({})",
1903	COLOR_SECTIONS.join(", ")
1904	));
1905	}
1906
1907	let id = source_path
1908	.file_stem()
1909	.and_then(\|s\| s.to_str())
1910	.ok_or("Invalid file name")?
1911	.to_string();
1912	validate_theme_id(&id)?;
1913
1914	std::fs::create_dir_all(custom_dir)
1915	.map_err(\|e\| format!("Failed to create {}: {}", custom_dir.display(), e))?;
1916
1917	let dest = custom_dir.join(format!("{id}.toml"));
1918	std::fs::copy(source_path, &dest).map_err(\|e\| format!("Failed to copy theme: {e}"))?;
1919
1920	Ok(parse_meta(&id, &table, true))
1921	}
1922
1923	/// Delete a custom theme by ID.
1924	///
1925	/// Only operates on `custom_dir` — bundled themes are not deletable through
1926	/// this entry point.
1927	pub fn delete_theme(custom_dir: &Path, id: &str) -> Result<(), String> {
1928	validate_theme_id(id)?;
1929
1930	let path = custom_dir.join(format!("{id}.toml"));
1931	if !path.is_file() {
1932	return Err(format!("Custom theme '{id}' not found"));
1933	}
1934
1935	std::fs::remove_file(&path).map_err(\|e\| format!("Failed to delete {}: {}", path.display(), e))
1936	}
1937
1938	/// A four-color preview for theme thumbnails: the representative swatch from
1939	/// each of the principal roles.
1940	#[derive(Debug, Clone, Serialize)]
1941	#[serde(rename_all = "camelCase")]
1942	pub struct ThemePreview {
1943	pub meta: ThemeMeta,
1944	/// Page background (`surface.page`).
1945	pub background: Option<String>,
1946	/// Body text (`content.primary`).
1947	pub foreground: Option<String>,
1948	/// Brand/interactive color (`action.primary`).
1949	pub accent: Option<String>,
1950	/// Divider/outline color (`line.border`).
1951	pub border: Option<String>,
1952	}
1953
1954	fn color_at(table: &toml::Table, section: &str, key: &str) -> Option<String> {
1955	table
1956	.get(section)
1957	.and_then(\|s\| s.as_table())
1958	.and_then(\|s\| s.get(key))
1959	.and_then(\|v\| v.as_str())
1960	.map(std::string::ToString::to_string)
1961	}
1962
1963	/// Load just the preview swatches for a theme — for UI thumbnails.
1964	pub fn load_theme_preview(dirs: &[(PathBuf, bool)], id: &str) -> Result<ThemePreview, String> {
1965	validate_theme_id(id)?;
1966
1967	let (path, is_custom) =
1968	find_theme_path(dirs, id).ok_or_else(\|\| format!("Theme '{id}' not found"))?;
1969
1970	let content = std::fs::read_to_string(&path)
1971	.map_err(\|e\| format!("Failed to read {}: {}", path.display(), e))?;
1972
1973	let table: toml::Table = content
1974	.parse()
1975	.map_err(\|e\| format!("Failed to parse {}: {}", path.display(), e))?;
1976
1977	Ok(ThemePreview {
1978	meta: parse_meta(id, &table, is_custom),
1979	background: color_at(&table, "surface", "page"),
1980	foreground: color_at(&table, "content", "primary"),
1981	accent: color_at(&table, "action", "primary"),
1982	border: color_at(&table, "line", "border"),
1983	})
1984	}
1985
1986	/// Export a theme to a user-chosen path.
1987	pub fn export_theme(dirs: &[(PathBuf, bool)], id: &str, dest_path: &Path) -> Result<(), String> {
1988	validate_theme_id(id)?;
1989
1990	let (source, _) = find_theme_path(dirs, id).ok_or_else(\|\| format!("Theme '{id}' not found"))?;
1991
1992	std::fs::copy(&source, dest_path).map_err(\|e\| format!("Failed to export theme: {e}"))?;
1993
1994	Ok(())
1995	}
1996
1997	/// The themes this crate ships, embedded at compile time.
1998	///
1999	/// `include_dir` is an implementation detail: the public API hands back plain
2000	/// `(id, toml_source)` pairs, so how the data is embedded can change without
2001	/// a breaking release.
2002	static EMBEDDED: include_dir::Dir<'static> =
2003	include_dir::include_dir!("$CARGO_MANIFEST_DIR/themes");
2004
2005	/// The themes this crate ships, as `(id, toml_source)` pairs.
2006	///
2007	/// This is the path-free way to reach the bundled set, for consumers that
2008	/// cannot rely on a directory existing at runtime: a crate pulled from
2009	/// crates.io lives in a registry checkout whose location is not knowable at
2010	/// compile time, so `include_dir!` and asset-bundling globs in the depending
2011	/// crate have nothing stable to point at. Embedding here and re-exporting the
2012	/// contents gives them one source of truth without a path.
2013	///
2014	/// Ordering follows the embedded directory and is not guaranteed; collect and
2015	/// sort by id where a stable order matters (a theme picker, say).
2016	pub fn embedded_themes() -> impl Iterator<Item = (&'static str, &'static str)> {
2017	EMBEDDED.files().filter_map(\|file\| {
2018	let path = file.path();
2019	if path.extension().and_then(\|e\| e.to_str()) != Some("toml") {
2020	return None;
2021	}
2022	let id = path.file_stem()?.to_str()?;
2023	Some((id, file.contents_utf8()?))
2024	})
2025	}
2026
2027	/// The theme directory this crate ships, for use as a build-from-source
2028	/// fallback.
2029	///
2030	/// Resolves against `makeover`'s own manifest directory, fixed at compile
2031	/// time, so it works from a path dependency and from a cargo git checkout
2032	/// alike. Installed systems should put their packaged theme directory ahead
2033	/// of this in the search path; this is the entry that keeps `cargo run` in a
2034	/// fresh clone from coming up with no themes at all.
2035	///
2036	/// Returns `None` when the directory is absent — a cargo cache that has been
2037	/// cleaned, or a vendored copy that dropped the data — so callers degrade to
2038	/// their remaining search path rather than failing.
2039	pub fn bundled_themes_dir() -> Option<PathBuf> {
2040	let themes = Path::new(env!("CARGO_MANIFEST_DIR")).join("themes");
2041	if themes.is_dir() { Some(themes) } else { None }
2042	}
2043
2044	#[cfg(test)]
2045	mod tests {
2046	use super::*;
2047	use std::fs;
2048
2049	// ---- id validation ----
2050
2051	#[test]
2052	fn validate_theme_id_alphanumeric() {
2053	assert!(validate_theme_id("darkmode").is_ok());
2054	assert!(validate_theme_id("Theme123").is_ok());
2055	}
2056
2057	#[test]
2058	fn validate_theme_id_hyphens_underscores() {
2059	assert!(validate_theme_id("dark-mode").is_ok());
2060	assert!(validate_theme_id("my_theme_v2").is_ok());
2061	}
2062
2063	#[test]
2064	fn validate_theme_id_rejects_path_traversal() {
2065	assert!(validate_theme_id("../etc/passwd").is_err());
2066	assert!(validate_theme_id("foo/bar").is_err());
2067	assert!(validate_theme_id("theme.toml").is_err());
2068	}
2069
2070	// ---- low-color terminals ----
2071
2072	#[test]
2073	fn the_ansi_palette_is_sixteen_distinct_colors() {
2074	let mut seen: Vec<(u8, u8, u8)> = ANSI_16.iter().map(\|c\| c.tuple()).collect();
2075	seen.sort_unstable();
2076	seen.dedup();
2077	assert_eq!(seen.len(), 16);
2078	}
2079
2080	// ---- the intent-to-slot table ----
2081
2082	// Sixteen slots, every one of them answered. A caller filling a terminal
2083	// palette has no fallback for a hole: the slot would keep whatever the
2084	// emulator started with, and one raw ANSI colour in a themed table is more
2085	// obviously wrong than all sixteen would be.
2086	#[test]
2087	fn every_ansi_slot_names_an_intent_on_either_polarity() {
2088	for variant in ["light", "dark", "high-contrast"] {
2089	for index in 0..16 {
2090	assert!(
2091	ansi_intent(index, variant).is_some(),
2092	"slot {index} unanswered on {variant}"
2093	);
2094	}
2095	assert_eq!(ansi_intent(16, variant), None);
2096	}
2097	}
2098
2099	// The property the four achromatic slots exist to hold: 0 is the darkest
2100	// tone the theme offers and 15 the lightest, in either polarity. A table
2101	// that pins slot 0 to `content.primary` passes this on a light theme and
2102	// inverts on a dark one, which is the bug the polarity split fixes.
2103	#[test]
2104	fn ansi_zero_is_darker_than_ansi_fifteen_on_either_polarity() {
2105	for id in ["akari-dawn", "akari-night"] {
2106	let theme = bundled(id);
2107	let slot = \|i: usize\| -> Rgb {
2108	let key = ansi_intent(i, &theme.meta.variant).expect("in range");
2109	Rgb::from_hex(theme.colors.get(key).expect("theme carries it")).expect("valid hex")
2110	};
2111	assert!(
2112	rel_luminance(slot(0)) < rel_luminance(slot(15)),
2113	"{id}: ANSI 0 {} should be darker than ANSI 15 {}",
2114	slot(0).to_hex(),
2115	slot(15).to_hex(),
2116	);
2117	}
2118	}
2119
2120	// The pair a greeter draws with: its container on 7, its text on 0. If
2121	// those collapse the login screen is one flat block, and slot 7 being a
2122	// surface rather than a text tone is what keeps them apart.
2123	#[test]
2124	fn the_container_slot_and_the_text_slot_stay_legible() {
2125	for id in ["akari-dawn", "akari-night"] {
2126	let theme = bundled(id);
2127	let slot = \|i: usize\| -> Rgb {
2128	let key = ansi_intent(i, &theme.meta.variant).expect("in range");
2129	Rgb::from_hex(theme.colors.get(key).expect("theme carries it")).expect("valid hex")
2130	};
2131	let contrast = wcag_contrast(slot(0), slot(7));
2132	assert!(contrast >= 4.5, "{id}: ANSI 0 on ANSI 7 is {contrast:.2}:1");
2133	}
2134	}
2135
2136	// The hues do not move with polarity. Red is the theme's danger tone on a
2137	// light theme and on a dark one, which is why only four slots are in the
2138	// polarity table at all.
2139	#[test]
2140	fn the_chromatic_slots_do_not_vary_with_polarity() {
2141	for index in [1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 14] {
2142	assert_eq!(
2143	ansi_intent(index, "light"),
2144	ansi_intent(index, "dark"),
2145	"slot {index} moved with polarity"
2146	);
2147	}
2148	}
2149
2150	fn bundled(id: &str) -> ThemeColors {
2151	let dir = bundled_themes_dir().expect("makeover ships its themes");
2152	load_theme(&[(dir, false)], id).expect("the akari pair ships")
2153	}
2154
2155	#[test]
2156	fn quantize_picks_the_obvious_entry() {
2157	let black = Rgb { r: 0, g: 0, b: 0 };
2158	let white = Rgb {
2159	r: 255,
2160	g: 255,
2161	b: 255,
2162	};
2163	assert_eq!(quantize(black, &ANSI_16), 0);
2164	assert_eq!(quantize(white, &ANSI_16), 15);
2165	}
2166
2167	// Nearest-entry quantization is per-color, so two colors a theme keeps
2168	// apart can arrive as one. These two are both closest to the palette's
2169	// light gray, and a border drawn in one on a page painted the other is not
2170	// drawn at all.
2171	#[test]
2172	fn two_colors_can_quantize_to_one_entry() {
2173	let page = Rgb::from_hex("#a8a8a8").unwrap();
2174	let border = Rgb::from_hex("#b4b4b4").unwrap();
2175
2176	assert_eq!(quantize(page, &ANSI_16), quantize(border, &ANSI_16));
2177	assert_ne!(
2178	quantize_against(border, page, &ANSI_16),
2179	quantize(page, &ANSI_16)
2180	);
2181	}
2182
2183	#[test]
2184	fn quantize_against_keeps_the_border_off_the_page() {
2185	let page = Rgb::from_hex("#e4ded6").unwrap();
2186	let border = Rgb::from_hex("#7f786d").unwrap();
2187
2188	let shown_page = ANSI_16[quantize(page, &ANSI_16)];
2189	let shown_border = ANSI_16[quantize_against(border, page, &ANSI_16)];
2190
2191	assert!(
2192	wcag_contrast(shown_border, shown_page) >= DISTINCT,
2193	"border {} on page {} is {:.2}:1",
2194	shown_border.to_hex(),
2195	shown_page.to_hex(),
2196	wcag_contrast(shown_border, shown_page)
2197	);
2198	}
2199
2200	// A color that already reads against its background is left where it is,
2201	// so this can be applied without redesigning what already worked.
2202	#[test]
2203	fn quantize_against_leaves_a_readable_color_alone() {
2204	let page = Rgb::from_hex("#e4ded6").unwrap();
2205	let text = Rgb::from_hex("#1a1816").unwrap();
2206
2207	assert_eq!(
2208	quantize_against(text, page, &ANSI_16),
2209	quantize(text, &ANSI_16)
2210	);
2211	}
2212
2213	// With nothing in the palette to satisfy the request, the most legible
2214	// entry is the answer. Returning the nearest one would return the
2215	// background itself, which is the failure this function exists to avoid.
2216	#[test]
2217	fn an_impossible_palette_gets_the_most_legible_entry() {
2218	let page = Rgb::from_hex("#ffffff").unwrap();
2219	let border = Rgb::from_hex("#fefefe").unwrap();
2220	let palette = [
2221	Rgb::from_hex("#ffffff").unwrap(),
2222	Rgb::from_hex("#fdfdfd").unwrap(),
2223	];
2224
2225	let chosen = palette[quantize_against(border, page, &palette)];
2226	assert_eq!(chosen.to_hex(), "#fdfdfd");
2227	}
2228
2229	// ---- meta ----
2230
2231	#[test]
2232	fn parse_meta_with_name_and_variant() {
2233	let table: toml::Table = "[meta]\nname = \"Nord\"\nvariant = \"light\"\n"
2234	.parse()
2235	.unwrap();
2236	let meta = parse_meta("nord", &table, false);
2237	assert_eq!(meta.id, "nord");
2238	assert_eq!(meta.name, "Nord");
2239	assert_eq!(meta.variant, "light");
2240	assert!(!meta.is_custom);
2241	}
2242
2243	#[test]
2244	fn parse_meta_defaults_to_id_and_dark() {
2245	let table: toml::Table = "".parse().unwrap();
2246	let meta = parse_meta("fallback", &table, true);
2247	assert_eq!(meta.name, "fallback");
2248	assert_eq!(meta.variant, "dark");
2249	assert!(meta.is_custom);
2250	}
2251
2252	// ---- color math (formulas must match the apps they came from) ----
2253
2254	#[test]
2255	fn rgb_hex_roundtrip() {
2256	assert_eq!(
2257	Rgb::from_hex("#6196FF").unwrap(),
2258	Rgb {
2259	r: 0x61,
2260	g: 0x96,
2261	b: 0xff
2262	}
2263	);
2264	assert_eq!(
2265	Rgb::from_hex("#abc").unwrap(),
2266	Rgb {
2267	r: 0xaa,
2268	g: 0xbb,
2269	b: 0xcc
2270	}
2271	);
2272	assert_eq!(
2273	Rgb {
2274	r: 0x61,
2275	g: 0x96,
2276	b: 0xff
2277	}
2278	.to_hex(),
2279	"#6196ff"
2280	);
2281	assert!(Rgb::from_hex("not-a-color").is_none());
2282	}
2283
2284	#[test]
2285	fn oklab_roundtrips_within_tolerance() {
2286	for hex in ["#6196ff", "#2e3440", "#ffffff", "#000000", "#c0392b"] {
2287	let c = Rgb::from_hex(hex).unwrap();
2288	let back = Rgb::from_oklab(c.to_oklab());
2289	// Gamut round-trip is near-exact (±1 per channel from rounding).
2290	assert!((c.r as i16 - back.r as i16).abs() <= 1, "{hex} r");
2291	assert!((c.g as i16 - back.g as i16).abs() <= 1, "{hex} g");
2292	assert!((c.b as i16 - back.b as i16).abs() <= 1, "{hex} b");
2293	}
2294	}
2295
2296	#[test]
2297	fn wcag_contrast_known_pairs() {
2298	let white = Rgb {
2299	r: 255,
2300	g: 255,
2301	b: 255,
2302	};
2303	let black = Rgb { r: 0, g: 0, b: 0 };
2304	assert!((wcag_contrast(white, black) - 21.0).abs() < 0.01);
2305	assert!((wcag_contrast(white, white) - 1.0).abs() < 0.01);
2306	}
2307
2308	#[test]
2309	fn readable_on_picks_by_wcag() {
2310	assert_eq!(
2311	readable_on(Rgb {
2312	r: 255,
2313	g: 255,
2314	b: 255
2315	}),
2316	Rgb { r: 0, g: 0, b: 0 }
2317	);
2318	assert_eq!(
2319	readable_on(Rgb { r: 0, g: 0, b: 0 }),
2320	Rgb {
2321	r: 255,
2322	g: 255,
2323	b: 255
2324	}
2325	);
2326	// A light blue action -> black text reads better.
2327	let action = Rgb::from_hex("#6196ff").unwrap();
2328	assert_eq!(readable_on(action), Rgb { r: 0, g: 0, b: 0 });
2329	}
2330
2331	#[test]
2332	fn lighten_darken_move_oklab_lightness() {
2333	let c = Rgb::from_hex("#6196ff").unwrap();
2334	let l0 = c.to_oklab().l;
2335	assert!(lighten(c, 0.05).to_oklab().l > l0);
2336	assert!(darken(c, 0.05).to_oklab().l < l0);
2337	}
2338
2339	#[test]
2340	fn mix_endpoints_and_midpoint() {
2341	let a = Rgb::from_hex("#000000").unwrap();
2342	let b = Rgb::from_hex("#6196ff").unwrap();
2343	assert_eq!(mix(a, b, 0.0), a);
2344	assert_eq!(mix(a, b, 1.0), b);
2345	// Midpoint sits between the endpoints in OKLab lightness.
2346	let mid = mix(a, b, 0.5).to_oklab().l;
2347	assert!(mid > a.to_oklab().l && mid < b.to_oklab().l);
2348	}
2349
2350	// ---- extract + resolve ----
2351
2352	fn nord_toml() -> &'static str {
2353	r##"
2354	[meta]
2355	name = "Nord"
2356	variant = "dark"
2357
2358	[surface]
2359	page = "#2e3440"
2360	raised = "#3b4252"
2361	sunken = "#434c5e"
2362	overlay = "#3b4252"
2363
2364	[content]
2365	primary = "#d8dee9"
2366	secondary = "#e5e9f0"
2367	muted = "#616e88"
2368
2369	[action]
2370	primary = "#81a1c1"
2371
2372	[status]
2373	danger = "#bf616a"
2374	success = "#a3be8c"
2375	warning = "#ebcb8b"
2376	info = "#88c0d0"
2377
2378	[line]
2379	border = "#4c566a"
2380
2381	[category]
2382	one = "#bf616a"
2383	two = "#a3be8c"
2384	three = "#81a1c1"
2385	four = "#ebcb8b"
2386	five = "#b48ead"
2387	six = "#88c0d0"
2388	"##
2389	}
2390
2391	#[test]
2392	fn extract_colors_reads_intent_sections() {
2393	let table: toml::Table = nord_toml().parse().unwrap();
2394	let colors = extract_colors(&table);
2395	assert_eq!(colors.get("surface.page").unwrap(), "#2e3440");
2396	assert_eq!(colors.get("content.primary").unwrap(), "#d8dee9");
2397	assert_eq!(colors.get("action.primary").unwrap(), "#81a1c1");
2398	assert_eq!(colors.get("status.danger").unwrap(), "#bf616a");
2399	assert_eq!(colors.get("line.border").unwrap(), "#4c566a");
2400	assert_eq!(colors.get("category.five").unwrap(), "#b48ead");
2401	assert_eq!(colors.len(), 19);
2402	}
2403
2404	#[test]
2405	fn resolve_base_intents_passthrough() {
2406	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2407	let t = resolve(&theme);
2408	assert_eq!(t.hex("surface-page"), Some("#2e3440"));
2409	assert_eq!(t.hex("content"), Some("#d8dee9")); // content.primary -> content
2410	// Not a passthrough: a tonal step of the ink, whatever the file said.
2411	assert_eq!(
2412	t.hex("content-muted").unwrap(),
2413	emphasized(
2414	Rgb::from_hex("#d8dee9").unwrap(),
2415	Rgb::from_hex("#2e3440").unwrap(),
2416	Emphasis::Muted
2417	)
2418	.to_hex()
2419	);
2420	assert_eq!(t.hex("action"), Some("#81a1c1"));
2421	assert_eq!(t.hex("danger"), Some("#bf616a"));
2422	assert_eq!(t.hex("border"), Some("#4c566a"));
2423	assert_eq!(t.hex("category-five"), Some("#b48ead"));
2424	}
2425
2426	#[test]
2427	fn a_tonal_step_lands_between_its_base_and_its_ground() {
2428	let ink = Rgb::from_hex("#d8dee9").unwrap();
2429	let page = Rgb::from_hex("#2e3440").unwrap();
2430	for step in [Emphasis::Full, Emphasis::Secondary, Emphasis::Muted] {
2431	let out = emphasized(ink, page, step).to_oklab().l;
2432	assert!(
2433	out <= ink.to_oklab().l && out >= page.to_oklab().l,
2434	"{step:?} left the interval between the ink and the page"
2435	);
2436	}
2437	assert_eq!(emphasized(ink, page, Emphasis::Full).to_hex(), ink.to_hex());
2438	}
2439
2440	#[test]
2441	fn tonal_steps_compose_rather_than_compound() {
2442	// Two steps toward one ground are one step toward it, which is what
2443	// makes deriving a family recursively well-defined. Within a rounding
2444	// step, since each hop lands back in 8-bit sRGB.
2445	let ink = Rgb::from_hex("#d8dee9").unwrap();
2446	let page = Rgb::from_hex("#2e3440").unwrap();
2447	let (a, b) = (0.12f32, 0.42f32);
2448	let twice = tonal(tonal(ink, page, a), page, b);
2449	let once = tonal(ink, page, a + b - a * b);
2450	let (x, y) = (twice.tuple(), once.tuple());
2451	for (l, r) in [(x.0, y.0), (x.1, y.1), (x.2, y.2)] {
2452	assert!(l.abs_diff(r) <= 1, "{twice:?} is not {once:?}");
2453	}
2454	}
2455
2456	#[test]
2457	fn a_ratio_outside_the_interval_is_clamped_rather_than_extrapolated() {
2458	let ink = Rgb::from_hex("#d8dee9").unwrap();
2459	let page = Rgb::from_hex("#2e3440").unwrap();
2460	assert_eq!(tonal(ink, page, -1.0).to_hex(), ink.to_hex());
2461	assert_eq!(tonal(ink, page, 2.0).to_hex(), page.to_hex());
2462	}
2463
2464	#[test]
2465	fn a_derived_token_key_is_the_family_plus_the_step() {
2466	assert_eq!(Emphasis::Muted.token("content"), "content-muted");
2467	assert_eq!(Emphasis::Secondary.token("content"), "content-secondary");
2468	assert_eq!(Emphasis::Full.token("content"), "content");
2469	// The point of the suffix being a property of the step: any family can
2470	// be grouped the same way without a second table saying what it means.
2471	assert_eq!(Emphasis::Muted.token("danger"), "danger-muted");
2472	}
2473
2474	#[test]
2475	fn every_shipped_theme_ramps_one_way() {
2476	// The property authoring the steps separately could not hold: three
2477	// themes had shipped a secondary lighter than their own primary, so a
2478	// renderer reading the emphasis order got the reverse of it.
2479	for (id, toml) in embedded_themes() {
2480	let theme = parse_theme_str(id, toml, false).unwrap();
2481	let t = resolve(&theme);
2482	let page = Rgb::from_hex(t.hex("surface-page").unwrap()).unwrap();
2483	let steps = ["content", "content-secondary", "content-muted"]
2484	.map(\|k\| wcag_contrast(Rgb::from_hex(t.hex(k).unwrap()).unwrap(), page));
2485	assert!(
2486	steps[0] > steps[1] && steps[1] > steps[2],
2487	"{id}: emphasis does not fall monotonically: {steps:?}"
2488	);
2489	}
2490	}
2491
2492	#[test]
2493	fn every_shipped_theme_takes_a_visible_first_step() {
2494	// The property that was missing when 2.6.0 derived these, and the
2495	// reason a pure-black ink shipped a secondary 3/255 away from it: the
2496	// ramp falling monotonically says nothing about how far it falls, and
2497	// a step nobody can see is not a step.
2498	for (id, toml) in embedded_themes() {
2499	let theme = parse_theme_str(id, toml, false).unwrap();
2500	let t = resolve(&theme);
2501	let ink = Rgb::from_hex(t.hex("content").unwrap()).unwrap();
2502	let secondary = Rgb::from_hex(t.hex("content-secondary").unwrap()).unwrap();
2503	let step = wcag_contrast(ink, secondary);
2504	assert!(
2505	step >= STEP_FLOOR,
2506	"{id}: secondary is {step:.2} from its ink, under the {STEP_FLOOR} floor"
2507	);
2508	}
2509	}
2510
2511	#[test]
2512	fn an_authored_emphasis_step_does_not_survive_loading() {
2513	// `nord_toml` still authors both, because a user's theme file might and
2514	// the answer has to be the same one.
2515	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2516	assert_ne!(theme.colors.get("content.muted").unwrap(), "#616e88");
2517	assert_ne!(theme.colors.get("content.secondary").unwrap(), "#e5e9f0");
2518	}
2519
2520	#[test]
2521	fn a_theme_with_no_page_keeps_what_it_authored() {
2522	// Skip-missing: there is nothing to read the step against, so the step
2523	// is not taken and a half-written theme does not lose a colour.
2524	let mut colors = HashMap::new();
2525	colors.insert("content.primary".to_string(), "#d8dee9".to_string());
2526	colors.insert("content.muted".to_string(), "#616e88".to_string());
2527	derive_tonal_steps(&mut colors);
2528	assert_eq!(colors.get("content.muted").unwrap(), "#616e88");
2529	}
2530
2531	#[test]
2532	fn resolve_derived_intents() {
2533	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2534	let t = resolve(&theme);
2535	let action = Rgb::from_hex("#81a1c1").unwrap();
2536	let page = Rgb::from_hex("#2e3440").unwrap();
2537	let _ = page;
2538	assert_eq!(
2539	t.hex("action-hover").unwrap(),
2540	lighten(action, 0.05).to_hex()
2541	);
2542	assert_eq!(
2543	t.hex("content-on-action").unwrap(),
2544	readable_on(action).to_hex()
2545	);
2546	assert_eq!(t.hex("focus-ring"), Some("#81a1c1"));
2547	assert_eq!(t.hex("hover-surface"), Some("#434c5e")); // = surface.sunken
2548	// Pruned by the usage audit (0 consumers): action-active, the *-surface
2549	// tints, selection, row-stripe. Apps that need them derive inline via
2550	// the shared mix().
2551	assert!(t.hex("action-active").is_none());
2552	assert!(t.hex("danger-surface").is_none());
2553	assert!(t.hex("selection").is_none());
2554	assert!(t.hex("row-stripe").is_none());
2555	}
2556
2557	#[test]
2558	fn resolve_bevel_intents() {
2559	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2560	let t = resolve(&theme);
2561	let raised = Rgb::from_hex("#3b4252").unwrap();
2562	assert_eq!(
2563	t.hex("bevel-light").unwrap(),
2564	lighten(raised, 0.14).to_hex()
2565	);
2566	assert_eq!(t.hex("bevel-dark").unwrap(), darken(raised, 0.18).to_hex());
2567	}
2568
2569	// A bevel is two edges around one face, so both edges have to be visibly off
2570	// that face or the control never resolves as lit. The lightening clamps at
2571	// the top of the ramp, which means a theme authoring a white raised surface
2572	// gets a highlight identical to the surface it is meant to sit on.
2573	//
2574	// The list is asserted rather than merely reported so that changing a theme
2575	// has to come here and say so. Shrinking it is the fix; growing it is a
2576	// regression in the theme, not in this derivation.
2577	#[test]
2578	fn bevel_edges_are_distinct_from_their_face() {
2579	const CANNOT_BEVEL: &[&str] = &["neobrute", "oxocarbon-light"];
2580
2581	let mut degenerate: Vec<String> = Vec::new();
2582	for (id, source) in embedded_themes() {
2583	let theme = parse_theme_str(id, source, false).unwrap();
2584	let t = resolve(&theme);
2585	let Some(raised) = t.hex("surface-raised") else {
2586	continue;
2587	};
2588	let light = t.hex("bevel-light").expect("raised implies bevel-light");
2589	let dark = t.hex("bevel-dark").expect("raised implies bevel-dark");
2590	if light == raised \|\| dark == raised {
2591	degenerate.push(id.to_string());
2592	}
2593	}
2594	degenerate.sort();
2595
2596	assert_eq!(
2597	degenerate, CANNOT_BEVEL,
2598	"themes whose raised surface cannot hold both bevel edges"
2599	);
2600	}
2601
2602	// The well inverts by theme, so assert both directions explicitly rather
2603	// than only the one the light themes happen to take.
2604	#[test]
2605	fn resolve_well_intent_follows_the_content_direction() {
2606	// nord is dark: light text on a dark raised surface, so the well goes
2607	// down and away from the text.
2608	let dark = resolve(&parse_theme_str("nord", nord_toml(), false).unwrap());
2609	let dark_raised = Rgb::from_hex("#3b4252").unwrap();
2610	assert_eq!(
2611	dark.hex("surface-well").unwrap(),
2612	darken(dark_raised, 0.09).to_hex()
2613	);
2614
2615	// The shipped light themes take the other branch.
2616	let goingson = embedded_themes()
2617	.into_iter()
2618	.find(\|(id, _)\| *id == "goingson")
2619	.expect("goingson is embedded")
2620	.1;
2621	let light = resolve(&parse_theme_str("goingson", goingson, false).unwrap());
2622	let light_raised = light
2623	.hex("surface-raised")
2624	.and_then(Rgb::from_hex)
2625	.expect("goingson authors a raised surface");
2626	assert_eq!(
2627	light.hex("surface-well").unwrap(),
2628	lighten(light_raised, 0.07).to_hex()
2629	);
2630	}
2631
2632	// A well is a fill, not an edge, so the only thing that makes it read is
2633	// being a different color from the surface it is cut into.
2634	//
2635	// Same shape and the same asserted-list discipline as
2636	// `bevel_edges_are_distinct_from_their_face`, and it bites the same two
2637	// themes for the same reason: a raised surface already at the top of the
2638	// ramp has nothing lighter to go to.
2639	#[test]
2640	fn well_is_distinct_from_its_face() {
2641	const CANNOT_WELL: &[&str] = &["neobrute", "oxocarbon-light"];
2642
2643	let mut degenerate: Vec<String> = Vec::new();
2644	for (id, source) in embedded_themes() {
2645	let theme = parse_theme_str(id, source, false).unwrap();
2646	let t = resolve(&theme);
2647	let Some(raised) = t.hex("surface-raised") else {
2648	continue;
2649	};
2650	let well = t.hex("surface-well").expect("raised implies surface-well");
2651	if well == raised {
2652	degenerate.push(id.to_string());
2653	}
2654	}
2655	degenerate.sort();
2656
2657	assert_eq!(
2658	degenerate, CANNOT_WELL,
2659	"themes whose raised surface cannot hold a well"
2660	);
2661	}
2662
2663	// Distinct is not the same as visible. A face near the top of the ramp
2664	// clamps partway rather than exactly, which yields a well that differs from
2665	// its face by a hex digit and by nothing the eye can find. `rosepine-dawn`
2666	// authors raised at L=0.987 and gets 0.009 of the 0.07 it asked for.
2667	//
2668	// Worth a separate test from the one above because the fix differs: an
2669	// exactly-degenerate theme needs its raised surface off the ramp end, while
2670	// these need it merely lowered. Both fixes are the theme's, not this
2671	// derivation's, which is why the list is asserted rather than warned about.
2672	#[test]
2673	fn well_is_visible_against_its_face() {
2674	// Below this, the well and its face are the same surface to a reader.
2675	const MIN_DELTA_L: f32 = 0.02;
2676	const CANNOT_HOLD_A_VISIBLE_WELL: &[&str] =
2677	&["neobrute", "oxocarbon-light", "rosepine-dawn"];
2678
2679	let mut invisible: Vec<String> = Vec::new();
2680	for (id, source) in embedded_themes() {
2681	let theme = parse_theme_str(id, source, false).unwrap();
2682	let t = resolve(&theme);
2683	let (Some(raised), Some(well)) = (
2684	t.hex("surface-raised").and_then(Rgb::from_hex),
2685	t.hex("surface-well").and_then(Rgb::from_hex),
2686	) else {
2687	continue;
2688	};
2689	if (well.to_oklab().l - raised.to_oklab().l).abs() < MIN_DELTA_L {
2690	invisible.push(id.to_string());
2691	}
2692	}
2693	invisible.sort();
2694
2695	assert_eq!(
2696	invisible, CANNOT_HOLD_A_VISIBLE_WELL,
2697	"themes whose well is too close to its face to read as one"
2698	);
2699	}
2700
2701	// The three tests above each measure a derived color against the face it was
2702	// derived from, so a theme can pass all of them and still have nothing lift
2703	// off anything: the face itself sits on the page, and that relationship is
2704	// the one a bevel needs in order to read as an object rather than as a
2705	// rectangle with decorated edges. makenot.work passed all three and could
2706	// not hold a bevel, which is what this covers.
2707	//
2708	// The threshold is picked against the ramps already ruled on rather than
2709	// against a round number. makenot.work shipped at 0.024 and was invisible,
2710	// was tried at 0.036 and rejected as marginal on badges and chips, and was
2711	// accepted at 0.058; goingson and audiofiles sit at 0.119 and 0.065. Every
2712	// ramp judged inadequate is below 0.036 and every one judged adequate is
2713	// above 0.058, so the line goes in the gap between them. Note the unit: this
2714	// is oklab L on 0 to 1, not the CIE L* on 0 to 100 that the theme files quote
2715	// in their comments, and the two are not interchangeable.
2716	//
2717	// Most of the list is imported palettes, which were authored for syntax
2718	// highlighting and owe our depth model nothing. Failing here says a theme
2719	// cannot hold a bevel, not that it is wrong. Shrinking the list is the fix;
2720	// growing it is a regression in the theme, not in this derivation.
2721	//
2722	// tokyonight left the list on 2026-08-15, and it is the only entry that could
2723	// leave without a judgment call about someone else's palette. Its page and
2724	// raised were the identical hex, so it had no ramp at all rather than a
2725	// shallow one, and the fix is upstream's own `bg_highlight` (#292e42, 0.079
2726	// above the page) rather than a color we picked. The other nineteen are
2727	// shallow ramps in published palettes, which is a different claim, and they
2728	// stay deferred until every app is migrated and eyeballed.
2729	#[test]
2730	fn raised_is_distinct_from_page() {
2731	// Below this, a raised surface and the page under it are one surface to
2732	// a reader, whichever direction the theme ramps in.
2733	const MIN_DELTA_L: f32 = 0.05;
2734	const CANNOT_LIFT_OFF_THE_PAGE: &[&str] = &[
2735	"akari-dawn",
2736	"akari-night",
2737	"ayu-light",
2738	"ayu-mirage",
2739	"catppuccin-latte",
2740	"catppuccin-mocha",
2741	"dawnfox",
2742	"dracula",
2743	"everforest",
2744	"flatwhite",
2745	"gruvbox-light",
2746	"neobrute",
2747	"one-dark",
2748	"oxocarbon-dark",
2749	"oxocarbon-light",
2750	"poimandres",
2751	"rosepine",
2752	"rosepine-dawn",
2753	"solarized-dark",
2754	];
2755
2756	let mut flat: Vec<String> = Vec::new();
2757	for (id, source) in embedded_themes() {
2758	let theme = parse_theme_str(id, source, false).unwrap();
2759	let t = resolve(&theme);
2760	let (Some(page), Some(raised)) = (
2761	t.hex("surface-page").and_then(Rgb::from_hex),
2762	t.hex("surface-raised").and_then(Rgb::from_hex),
2763	) else {
2764	continue;
2765	};
2766	if (raised.to_oklab().l - page.to_oklab().l).abs() < MIN_DELTA_L {
2767	flat.push(id.to_string());
2768	}
2769	}
2770	flat.sort();
2771
2772	assert_eq!(
2773	flat, CANNOT_LIFT_OFF_THE_PAGE,
2774	"themes whose raised surface is too close to the page to lift off it"
2775	);
2776	}
2777
2778	// What the bevel pair does on a sixteen-color terminal, measured across the
2779	// shipped set rather than assumed. Two results, both load-bearing for a
2780	// consumer that has to render one there.
2781	//
2782	// Exactly one edge survives, never both. A raised face quantizes onto one of
2783	// the palette's three grays, and the palette is too coarse to hold anything
2784	// between that entry and its neighbour, so whichever edge is pushed toward
2785	// the end of the ramp the face already sits on lands back on the face. Light
2786	// themes and most dark ones keep the shadow and lose the highlight; a face
2787	// that quantizes to black keeps the highlight and loses the shadow.
2788	//
2789	// So a low-color consumer draws the single edge it can render, on the side
2790	// the palette left it, rather than a bevel that resolves on two sides.
2791	//
2792	// And `quantize_against` is the wrong function for this pair, though it is
2793	// the right one for a border. It answers "nearest entry that clears DISTINCT
2794	// against the background", which has no notion of direction, so both edges
2795	// are pushed onto the same contrasting entry and the bevel inverts on one
2796	// side. Plain `quantize` keeps them apart and in the right order.
2797	#[test]
2798	fn a_sixteen_color_terminal_gets_one_bevel_edge_and_not_two() {
2799	for (id, source) in embedded_themes() {
2800	let theme = parse_theme_str(id, source, false).unwrap();
2801	let t = resolve(&theme);
2802	let (Some(face), Some(light), Some(dark)) = (
2803	t.hex("surface-raised").and_then(Rgb::from_hex),
2804	t.hex("bevel-light").and_then(Rgb::from_hex),
2805	t.hex("bevel-dark").and_then(Rgb::from_hex),
2806	) else {
2807	continue;
2808	};
2809
2810	let face_index = quantize(face, &ANSI_16);
2811	let light_survives = quantize(light, &ANSI_16) != face_index;
2812	let dark_survives = quantize(dark, &ANSI_16) != face_index;
2813	assert!(
2814	light_survives != dark_survives,
2815	"{id}: expected exactly one bevel edge to survive 16 colors, \
2816	highlight {light_survives} shadow {dark_survives}"
2817	);
2818
2819	// Direction-blind, so it collapses the pair it is asked to separate.
2820	assert_eq!(
2821	quantize_against(light, face, &ANSI_16),
2822	quantize_against(dark, face, &ANSI_16),
2823	"{id}: quantize_against is expected to be unusable for a bevel pair"
2824	);
2825	}
2826	}
2827
2828	// 256 colors is where the bevel starts working. At 16 every shipped theme
2829	// loses an edge; here all but the five whose raised surface sits at the very
2830	// top of the ramp keep both, and those five fail for the reason they fail in
2831	// truecolor rather than for a palette reason.
2832	//
2833	// Three of them cannot bevel at any depth, so they are the
2834	// `bevel_edges_are_distinct_from_their_face` set. The other two are new here:
2835	// they hold a highlight in 24-bit, but not one wide enough to survive
2836	// rounding onto the cube.
2837	#[test]
2838	fn two_hundred_fifty_six_colors_keep_both_bevel_edges() {
2839	const LOSES_AN_EDGE: &[&str] = &[
2840	"gruvbox-light",
2841	"neobrute",
2842	"oxocarbon-light",
2843	"rosepine-dawn",
2844	];
2845
2846	let mut lost: Vec<String> = Vec::new();
2847	for (id, source) in embedded_themes() {
2848	let theme = parse_theme_str(id, source, false).unwrap();
2849	let t = resolve(&theme);
2850	let (Some(face), Some(light), Some(dark)) = (
2851	t.hex("surface-raised").and_then(Rgb::from_hex),
2852	t.hex("bevel-light").and_then(Rgb::from_hex),
2853	t.hex("bevel-dark").and_then(Rgb::from_hex),
2854	) else {
2855	continue;
2856	};
2857
2858	// Against the fixed region, which is what a consumer should use: a
2859	// match in the low sixteen is a match against a repaintable color.
2860	let f = quantize(face, ANSI_240);
2861	let l = quantize(light, ANSI_240);
2862	let d = quantize(dark, ANSI_240);
2863	if l == f \|\| d == f \|\| l == d {
2864	lost.push(id.to_string());
2865	}
2866	}
2867	lost.sort();
2868
2869	assert_eq!(
2870	lost, LOSES_AN_EDGE,
2871	"themes that cannot hold a two-tone bevel on a 256-color terminal"
2872	);
2873	}
2874
2875	#[test]
2876	fn the_256_table_has_its_three_regions() {
2877	// Index is the escape-sequence index, so the low sixteen must match.
2878	assert_eq!(ANSI_256[..16], ANSI_16);
2879	// The cube's corners, at both ends and one interior level.
2880	assert_eq!(ANSI_256[16].tuple(), (0, 0, 0));
2881	assert_eq!(ANSI_256[231].tuple(), (255, 255, 255));
2882	assert_eq!(ANSI_256[16 + 36 * 2 + 6 * 3 + 4].tuple(), (135, 175, 215));
2883	// The gray ramp runs 8 to 238 and contains neither black nor white.
2884	assert_eq!(ANSI_256[232].tuple(), (8, 8, 8));
2885	assert_eq!(ANSI_256[255].tuple(), (238, 238, 238));
2886	// The fixed region is the table minus the repaintable colors.
2887	assert_eq!(ANSI_240.len(), 240);
2888	assert_eq!(ANSI_240[0], ANSI_256[ANSI_240_OFFSET]);
2889	}
2890
2891	#[test]
2892	fn resolve_overlay_is_dark_translucent_scrim() {
2893	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2894	let t = resolve(&theme);
2895	let overlay = t.hex("overlay").unwrap();
2896	assert!(
2897	overlay.starts_with("rgba("),
2898	"overlay is translucent: {overlay}"
2899	);
2900	assert!(overlay.ends_with(", 0.5)"));
2901	// The scrim tone is anchored very dark regardless of theme.
2902	let inner = overlay
2903	.trim_start_matches("rgba(")
2904	.trim_end_matches(", 0.5)");
2905	let parts: Vec<u8> = inner.split(", ").map(\|p\| p.parse().unwrap()).collect();
2906	let scrim = Rgb {
2907	r: parts[0],
2908	g: parts[1],
2909	b: parts[2],
2910	};
2911	assert!(scrim.to_oklab().l < 0.2, "scrim must be near-black");
2912	}
2913
2914	/// Every shipped theme derives it, on both polarities, and it is always a
2915	/// near-black translucent tone. A shadow tinted to a dark theme's own
2916	/// lightness would not read as one.
2917	#[test]
2918	fn elevation_is_a_near_black_cast_on_every_theme() {
2919	for (id, source) in embedded_themes() {
2920	let theme = parse_theme_str(id, source, false).unwrap();
2921	let t = resolve(&theme);
2922	let Some(elevation) = t.hex("elevation") else {
2923	panic!("{id} derives no elevation");
2924	};
2925	assert!(
2926	elevation.starts_with("rgba(") && elevation.ends_with(", 0.18)"),
2927	"{id}: elevation is translucent: {elevation}"
2928	);
2929	let inner = elevation
2930	.trim_start_matches("rgba(")
2931	.trim_end_matches(", 0.18)");
2932	let parts: Vec<u8> = inner.split(", ").map(\|p\| p.parse().unwrap()).collect();
2933	let cast = Rgb {
2934	r: parts[0],
2935	g: parts[1],
2936	b: parts[2],
2937	};
2938	assert!(
2939	cast.to_oklab().l < 0.2,
2940	"{id}: a cast shadow must be near-black, got {elevation}"
2941	);
2942	}
2943	}
2944
2945	/// The scrim and the cast share an anchor and differ only in weight. Stated
2946	/// as a test because the two are easy to drift apart, and a scrim that
2947	/// stopped matching the shadow under the thing it dims would show.
2948	#[test]
2949	fn elevation_and_the_scrim_are_the_same_tone() {
2950	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2951	let t = resolve(&theme);
2952	let scrim = t.hex("overlay").unwrap();
2953	let cast = t.hex("elevation").unwrap();
2954	assert_eq!(
2955	scrim.trim_end_matches(", 0.5)"),
2956	cast.trim_end_matches(", 0.18)"),
2957	);
2958	}
2959
2960	/// The accessor that makes a translucent intent reachable from something
2961	/// that is not a stylesheet. Both spellings, and an opaque token answers
2962	/// 255 so a caller need not know which kind it asked for.
2963	#[test]
2964	fn rgba_reads_both_spellings() {
2965	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
2966	let t = resolve(&theme);
2967
2968	let (_, _, _, opaque) = t.rgba("surface-page").expect("page is a hex token");
2969	assert_eq!(opaque, 255);
2970
2971	let (r, g, b, alpha) = t.rgba("elevation").expect("elevation is translucent");
2972	assert_eq!(alpha, 46, "0.18 of 255");
2973	assert_eq!(t.rgb("elevation"), None, "rgb declines to drop the alpha");
2974
2975	let (sr, sg, sb, scrim) = t.rgba("overlay").expect("overlay is translucent");
2976	assert_eq!((sr, sg, sb), (r, g, b), "one tone, two weights");
2977	assert_eq!(scrim, 128);
2978	}
2979
2980	#[test]
2981	fn resolve_drops_non_hex_base_intent() {
2982	// A base intent that isn't a hex color must never reach the resolved
2983	// token set (it would otherwise be inlined verbatim into a <style>
2984	// block). Skipped like a missing intent; valid siblings survive.
2985	let theme = parse_theme_str(
2986	"x",
2987	"[surface]\npage = \"</style><script>alert(1)</script>\"\n[content]\nprimary = \"#111111\"\n",
2988	false,
2989	)
2990	.unwrap();
2991	let t = resolve(&theme);
2992	assert!(
2993	t.hex("surface-page").is_none(),
2994	"non-hex base intent leaked"
2995	);
2996	assert_eq!(t.hex("content").unwrap(), "#111111");
2997	// The injected markup appears in no resolved value.
2998	assert!(!t.intents.values().any(\|v\| v.contains('<')));
2999	}
3000
3001	#[test]
3002	fn resolve_skips_derived_when_source_missing() {
3003	// No [action] => no action-derived tokens.
3004	let theme = parse_theme_str(
3005	"x",
3006	"[surface]\npage = \"#000000\"\n[line]\nborder = \"#222222\"\n",
3007	false,
3008	)
3009	.unwrap();
3010	let t = resolve(&theme);
3011	assert!(t.hex("action").is_none());
3012	assert!(t.hex("action-hover").is_none());
3013	assert!(t.hex("selection").is_none());
3014	assert_eq!(
3015	t.hex("border-strong").unwrap(),
3016	darken(Rgb::from_hex("#222222").unwrap(), 0.05).to_hex()
3017	);
3018	}
3019
3020	#[test]
3021	fn rgb_accessor_for_native_consumers() {
3022	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
3023	let t = resolve(&theme);
3024	assert_eq!(t.rgb("action"), Some((0x81, 0xa1, 0xc1)));
3025	assert_eq!(t.rgb("nonexistent"), None);
3026	}
3027
3028	// ---- css emit ----
3029
3030	#[test]
3031	fn intent_css_vars_wraps_root_and_includes_tokens() {
3032	let theme = parse_theme_str("nord", nord_toml(), false).unwrap();
3033	let css = intent_css_vars(&resolve(&theme));
3034	assert!(css.starts_with(":root {\n"));
3035	assert!(css.contains(" --surface-page: #2e3440;\n"));
3036	assert!(css.contains(" --danger: #bf616a;\n"));
3037	assert!(css.contains(" --action-hover: "));
3038	assert!(css.trim_end().ends_with('}'));
3039	}
3040
3041	// ---- typography ----
3042
3043	#[test]
3044	fn the_font_tokens_are_two_names_and_each_ends_at_a_system_generic() {
3045	let css = typography_css_vars();
3046	assert!(css.starts_with(":root {\n"));
3047	assert!(css.contains(" --font-mono: \"Quasi Mono\", monospace;\n"));
3048	assert!(css.contains(" --font-sans: \"Quasi Body\", sans-serif;\n"));
3049
3050	// Layer 2 is one hop and no further. A third entry in either stack is
3051	// the shape the standard exists to delete: a chain nobody can predict
3052	// the metrics of, which is what `--font-sans: -apple-system,
3053	// BlinkMacSystemFont, 'Segoe UI', Roboto, ...` was in three apps.
3054	for stack in [FONT_MONO, FONT_SANS] {
3055	assert_eq!(stack.split(',').count(), 2, "{stack} is not one hop");
3056	}
3057
3058	// Two tokens, and no others. `--font-body`, `--font-heading` and
3059	// `--font-display` are gone or out of scope; a token appearing here
3060	// is a fifth answer to a question that has two.
3061	assert_eq!(css.matches("--font-").count(), 2);
3062	}
3063
3064	#[test]
3065	fn every_font_face_names_the_weight_range_because_the_mono_opens_at_200() {
3066	let css = font_face_css("/static/fonts");
3067
3068	assert_eq!(css.matches("@font-face").count(), 2);
3069	assert!(css.contains("src: url(\"/static/fonts/QuasiMono.woff2\") format(\"woff2\");"));
3070	assert!(css.contains("src: url(\"/static/fonts/QuasiBody.woff2\") format(\"woff2\");"));
3071
3072	// The trap. Atkinson Hyperlegible Mono's default instance is
3073	// ExtraLight and the cut keeps the axis, so a `@font-face` that omits
3074	// the range draws the whole UI at 200.
3075	assert_eq!(css.matches("font-weight: 200 800;").count(), 2);
3076
3077	// The families have to be exactly what the tokens ask for, or the
3078	// stack falls through to the generic and the face is dead weight.
3079	for family in [FONT_MONO, FONT_SANS] {
3080	let quoted = family.split(',').next().unwrap();
3081	assert!(css.contains(&format!("font-family: {quoted};")));
3082	}
3083	}
3084
3085	#[test]
3086	fn a_trailing_slash_on_the_base_url_does_not_double_it() {
3087	assert_eq!(font_face_css("fonts/"), font_face_css("fonts"));
3088	assert!(font_face_css("fonts").contains("url(\"fonts/QuasiMono.woff2\")"));
3089	}
3090
3091	// ---- typography, layer 0 ----
3092
3093	/// The live case: MNW's Young Serif, which reached the page through a
3094	/// hand-maintained `@font-face` and a `--font-heading` nothing else knew
3095	/// about.
3096	fn young_serif() -> FontOverride {
3097	FontOverride::new(FontSlot::Display, "\"Young Serif\", serif")
3098	.with_face(FontFace::new("Young Serif", ["ysrf.woff2", "ysrf.ttf"]))
3099	}
3100
3101	#[test]
3102	fn the_house_layer_alone_is_exactly_what_the_free_functions_emit() {
3103	let t = Typography::house("/static/fonts");
3104	assert_eq!(t.font_face_css(), font_face_css("/static/fonts"));
3105	assert_eq!(t.css_vars(), typography_css_vars());
3106	}
3107
3108	#[test]
3109	fn an_unoverridden_display_slot_defines_no_token_at_all() {
3110	// Not "defined empty": undefined, so the consumer's own fallback in
3111	// `var(--font-display, …)` renders. The MNW embeds depend on it.
3112	let t = Typography::house("fonts");
3113	assert!(!t.css_vars().contains("--font-display"));
3114	assert_eq!(t.resolve(FontSlot::Display), None);
3115	assert_eq!(t.css_vars().matches("--font-").count(), 2);
3116	}
3117
3118	#[test]
3119	fn an_override_adds_its_token_and_its_face_without_touching_the_house_two() {
3120	let t = Typography::house("/static/fonts").with_override(young_serif());
3121
3122	assert!(
3123	t.css_vars()
3124	.contains(" --font-display: \"Young Serif\", serif;\n")
3125	);
3126	assert!(
3127	t.css_vars()
3128	.contains(" --font-mono: \"Quasi Mono\", monospace;\n")
3129	);
3130	assert!(
3131	t.css_vars()
3132	.contains(" --font-sans: \"Quasi Body\", sans-serif;\n")
3133	);
3134	assert_eq!(t.resolve(FontSlot::Display), Some("\"Young Serif\", serif"));
3135
3136	let faces = t.font_face_css();
3137	assert_eq!(faces.matches("@font-face").count(), 3);
3138	assert!(faces.contains("font-family: \"Young Serif\";"));
3139	assert!(faces.contains("url(\"/static/fonts/ysrf.woff2\") format(\"woff2\")"));
3140	assert!(faces.contains("url(\"/static/fonts/ysrf.ttf\") format(\"truetype\")"));
3141
3142	// The house faces still come first, so a product face never shadows a
3143	// slot it did not claim.
3144	assert!(faces.find("Quasi Mono").unwrap() < faces.find("Young Serif").unwrap());
3145	}
3146
3147	#[test]
3148	fn overriding_mono_or_sans_replaces_the_house_stack_rather_than_adding_to_it() {
3149	// Nobody wants this today. A layer that only permits overriding the
3150	// slot nobody describes is the exemption restated, not a layer.
3151	let t = Typography::house("fonts").with_override(FontOverride::new(
3152	FontSlot::Mono,
3153	"\"Departure Mono\", monospace",
3154	));
3155
3156	assert!(
3157	t.css_vars()
3158	.contains(" --font-mono: \"Departure Mono\", monospace;\n")
3159	);
3160	assert!(!t.css_vars().contains("Quasi Mono"));
3161	assert_eq!(t.css_vars().matches("--font-").count(), 2);
3162	}
3163
3164	#[test]
3165	#[should_panic(expected = "--font-display is overridden twice")]
3166	fn a_second_override_of_one_slot_is_a_vocabulary_bug_and_says_so() {
3167	let _ = Typography::house("fonts")
3168	.with_override(young_serif())
3169	.with_override(FontOverride::new(FontSlot::Display, "\"Reglo\", serif"));
3170	}
3171
3172	#[test]
3173	fn an_absolute_source_is_taken_as_written_and_a_relative_one_joins_the_base() {
3174	let t = Typography::house("/static/fonts").with_override(
3175	FontOverride::new(FontSlot::Display, "\"Reglo\", serif").with_face(
3176	FontFace::new(
3177	"Reglo",
3178	["Reglo-Bold.woff2", "https://cdn.example/reglo.woff2"],
3179	)
3180	.weight("700"),
3181	),
3182	);
3183	let faces = t.font_face_css();
3184	assert!(faces.contains("url(\"/static/fonts/Reglo-Bold.woff2\")"));
3185	assert!(faces.contains("url(\"https://cdn.example/reglo.woff2\")"));
3186	assert!(faces.contains(" font-weight: 700;\n"));
3187	}
3188
3189	#[test]
3190	fn an_unrecognised_extension_gets_no_format_hint_rather_than_a_guessed_one() {
3191	let t = Typography::house("fonts").with_override(
3192	FontOverride::new(FontSlot::Display, "\"Odd\", serif")
3193	.with_face(FontFace::new("Odd", ["odd.eot"])),
3194	);
3195	assert!(t.font_face_css().contains("url(\"fonts/odd.eot\");"));
3196	assert!(!t.font_face_css().contains("format(\"eot\")"));
3197	}
3198
3199	#[test]
3200	fn css_puts_the_faces_before_the_tokens_that_name_them() {
3201	let t = Typography::house("fonts").with_override(young_serif());
3202	let css = t.css();
3203	assert!(css.starts_with("@font-face"));
3204	assert!(css.find("@font-face").unwrap() < css.find(":root").unwrap());
3205	}
3206
3207	// ---- loading / fs ----
3208
3209	#[test]
3210	fn load_and_resolve_round_trip() {
3211	let dir = tempfile::tempdir().unwrap();
3212	fs::write(dir.path().join("nord.toml"), nord_toml()).unwrap();
3213	let dirs = vec![(dir.path().to_path_buf(), false)];
3214	let t = load_semantic(&dirs, "nord").unwrap();
3215	assert_eq!(t.meta.name, "Nord");
3216	assert_eq!(t.hex("action"), Some("#81a1c1"));
3217	}
3218
3219	#[test]
3220	fn load_theme_rejects_invalid_id() {
3221	assert!(load_theme(&[], "../evil").is_err());
3222	}
3223
3224	fn meta(id: &str, variant: &str) -> ThemeMeta {
3225	ThemeMeta {
3226	id: id.to_string(),
3227	name: id.to_string(),
3228	variant: variant.to_string(),
3229	is_custom: false,
3230	}
3231	}
3232
3233	fn defaults() -> ThemeDefaults {
3234	ThemeDefaults::new("flatwhite", "nord")
3235	}
3236
3237	// The three the shipped themes actually declare.
3238	#[test]
3239	fn every_shipped_variant_parses() {
3240	assert_eq!(Variant::parse("light"), Some(Variant::Light));
3241	assert_eq!(Variant::parse("dark"), Some(Variant::Dark));
3242	assert_eq!(Variant::parse("high-contrast"), Some(Variant::HighContrast));
3243	assert_eq!(Variant::parse("sepia"), None);
3244	}
3245
3246	// parse_meta already defaults a missing variant to dark, so an
3247	// unrecognized one reading as light would have the crate disagreeing with
3248	// itself. alloy_tui did exactly that before this existed.
3249	#[test]
3250	fn an_unrecognized_variant_reads_the_way_a_missing_one_does() {
3251	assert_eq!(Variant::from("sepia"), Variant::Dark);
3252	assert_eq!(Variant::from(""), Variant::Dark);
3253
3254	let missing: toml::Table = "[meta]\nname = \"X\"\n".parse().unwrap();
3255	assert_eq!(parse_meta("x", &missing, false).kind(), Variant::Dark);
3256	}
3257
3258	#[test]
3259	fn a_selection_round_trips_through_any_store() {
3260	for (stored, expect) in [
3261	(Some("system"), ThemeSelection::Follow),
3262	(None, ThemeSelection::Follow),
3263	(Some(""), ThemeSelection::Follow),
3264	(Some(" "), ThemeSelection::Follow),
3265	(Some("nord"), ThemeSelection::Fixed("nord".into())),
3266	] {
3267	let parsed = ThemeSelection::parse(stored);
3268	assert_eq!(parsed, expect, "{stored:?}");
3269	assert_eq!(
3270	ThemeSelection::parse(Some(parsed.as_str())),
3271	expect,
3272	"what is written reads back as what was meant",
3273	);
3274	}
3275	}
3276
3277	// Nothing saved is follow-the-system, which is what Balanced Breakfast
3278	// expressed as an absent value and GoingsOn as a sentinel. Both are now the
3279	// same thing.
3280	#[test]
3281	fn nothing_chosen_yet_is_follow() {
3282	assert_eq!(ThemeSelection::default(), ThemeSelection::Follow);
3283	}
3284
3285	#[test]
3286	fn a_fixed_selection_wins_when_its_theme_is_installed() {
3287	let available = [meta("nord", "dark"), meta("flatwhite", "light")];
3288	let fixed = ThemeSelection::Fixed("nord".into());
3289	assert_eq!(
3290	fixed.resolve(Variant::Light, &defaults(), &available),
3291	"nord",
3292	"a chosen theme is not overridden by the ambient mode",
3293	);
3294	}
3295
3296	// Themes are deletable in three of the four apps. Handing back an id that
3297	// will fail to load only moves the error somewhere less helpful.
3298	#[test]
3299	fn a_fixed_selection_whose_theme_is_gone_falls_back() {
3300	let available = [meta("nord", "dark"), meta("flatwhite", "light")];
3301	let fixed = ThemeSelection::Fixed("deleted".into());
3302	assert_eq!(
3303	fixed.resolve(Variant::Light, &defaults(), &available),
3304	"flatwhite",
3305	);
3306	}
3307
3308	#[test]
3309	fn follow_picks_the_apps_default_for_the_ambient_mode() {
3310	let available = [meta("nord", "dark"), meta("flatwhite", "light")];
3311	let follow = ThemeSelection::Follow;
3312	assert_eq!(
3313	follow.resolve(Variant::Dark, &defaults(), &available),
3314	"nord",
3315	);
3316	assert_eq!(
3317	follow.resolve(Variant::Light, &defaults(), &available),
3318	"flatwhite",
3319	);
3320	}
3321
3322	// The behaviour Balanced Breakfast could not have: following the system
3323	// into a theme the user installed, when the app's own default is absent.
3324	#[test]
3325	fn follow_uses_any_installed_theme_of_the_right_variant() {
3326	let available = [meta("solarized-light", "light"), meta("mine", "dark")];
3327	assert_eq!(
3328	ThemeSelection::Follow.resolve(Variant::Dark, &defaults(), &available),
3329	"mine",
3330	"the app's `nord` is not installed, but a dark theme is",
3331	);
3332	}
3333
3334	// Always returns something: an app with no theme directory gets the id it
3335	// ships with, and the load error it would have had anyway.
3336	#[test]
3337	fn an_empty_catalog_still_names_the_apps_default() {
3338	assert_eq!(
3339	ThemeSelection::Follow.resolve(Variant::Dark, &defaults(), &[]),
3340	"nord",
3341	);
3342	}
3343
3344	#[test]
3345	fn high_contrast_falls_back_to_dark_unless_named() {
3346	let plain = defaults();
3347	assert_eq!(plain.for_variant(Variant::HighContrast), "nord");
3348
3349	let named = defaults().high_contrast("sharp");
3350	assert_eq!(named.for_variant(Variant::HighContrast), "sharp");
3351	}
3352
3353	// The bug this builder exists to prevent: the Alloy console pushed the
3354	// user's directory first under a comment reading "highest precedence
3355	// first", when both consumers of this vector resolve last-wins. A custom
3356	// theme lost to the packaged one of the same id.
3357	#[test]
3358	fn the_users_own_themes_outrank_everything() {
3359	let root = tempfile::tempdir().unwrap();
3360	let make = \|name: &str\| {
3361	let dir = root.path().join(name);
3362	std::fs::create_dir_all(&dir).unwrap();
3363	dir
3364	};
3365	let (bundled, system, custom) = (make("bundled"), make("system"), make("custom"));
3366
3367	let dirs = ThemeDirs::new()
3368	.custom(Some(custom.clone()))
3369	.bundled(Some(bundled.clone()))
3370	.system(Some(system.clone()))
3371	.build();
3372
3373	assert_eq!(
3374	dirs,
3375	vec![(bundled, false), (system, false), (custom.clone(), true)],
3376	"lowest precedence first, whatever order the tiers were added in",
3377	);
3378	assert!(dirs.last().unwrap().1, "only the user's tier is custom");
3379
3380	// And the ordering means what the consumers think it means.
3381	for dir in dirs.iter().map(\|(dir, _)\| dir) {
3382	std::fs::write(dir.join("shared.toml"), "[meta]\nname = \"x\"\n").unwrap();
3383	}
3384	assert_eq!(
3385	find_theme_path(&dirs, "shared").unwrap().0,
3386	custom.join("shared.toml"),
3387	"the user's copy is the one that loads",
3388	);
3389	}
3390
3391	#[test]
3392	fn a_directory_that_does_not_exist_is_dropped() {
3393	let root = tempfile::tempdir().unwrap();
3394	let real = root.path().join("real");
3395	std::fs::create_dir_all(&real).unwrap();
3396
3397	let dirs = ThemeDirs::new()
3398	.bundled(Some(root.path().join("nope")))
3399	.system(None)
3400	.custom(Some(real.clone()))
3401	.build();
3402
3403	assert_eq!(dirs, vec![(real, true)]);
3404	}
3405
3406	// A Tauri app has two bundled tiers: the resource dir in production and the
3407	// tree build.rs materialized for a dev run with no resource dir.
3408	#[test]
3409	fn more_than_one_bundled_tier_is_allowed() {
3410	let root = tempfile::tempdir().unwrap();
3411	let (first, second) = (root.path().join("a"), root.path().join("b"));
3412	std::fs::create_dir_all(&first).unwrap();
3413	std::fs::create_dir_all(&second).unwrap();
3414
3415	let dirs = ThemeDirs::new()
3416	.bundled(Some(first.clone()))
3417	.bundled(Some(second.clone()))
3418	.build();
3419	assert_eq!(dirs, vec![(first, false), (second, false)]);
3420	}
3421
3422	#[test]
3423	fn list_themes_from_dirs_finds_toml_files() {
3424	let dir = tempfile::tempdir().unwrap();
3425	fs::write(dir.path().join("t.toml"), "[meta]\nname = \"T\"\n").unwrap();
3426	fs::write(dir.path().join("x.txt"), "ignored").unwrap();
3427	let dirs = vec![(dir.path().to_path_buf(), false)];
3428	let themes = list_themes_from_dirs(&dirs);
3429	assert_eq!(themes.len(), 1);
3430	assert_eq!(themes[0].id, "t");
3431	}
3432
3433	#[test]
3434	fn find_theme_path_reverse_priority() {
3435	let d1 = tempfile::tempdir().unwrap();
3436	let d2 = tempfile::tempdir().unwrap();
3437	fs::write(d1.path().join("s.toml"), "[meta]\n").unwrap();
3438	fs::write(d2.path().join("s.toml"), "[meta]\n").unwrap();
3439	let dirs = vec![
3440	(d1.path().to_path_buf(), false),
3441	(d2.path().to_path_buf(), true),
3442	];
3443	let (path, is_custom) = find_theme_path(&dirs, "s").unwrap();
3444	assert!(is_custom);
3445	assert_eq!(path, d2.path().join("s.toml"));
3446	}
3447
3448	#[test]
3449	fn import_theme_valid_and_rejects_empty() {
3450	let src_dir = tempfile::tempdir().unwrap();
3451	let custom_dir = tempfile::tempdir().unwrap();
3452
3453	let good = src_dir.path().join("my-theme.toml");
3454	fs::write(&good, "[surface]\npage = \"#1a1b26\"\n").unwrap();
3455	let meta = import_theme(&good, custom_dir.path()).unwrap();
3456	assert_eq!(meta.id, "my-theme");
3457	assert!(custom_dir.path().join("my-theme.toml").exists());
3458
3459	let empty = src_dir.path().join("empty.toml");
3460	fs::write(&empty, "[meta]\nname = \"E\"\n").unwrap();
3461	assert!(import_theme(&empty, custom_dir.path()).is_err());
3462	}
3463
3464	#[test]
3465	fn import_theme_rejects_invalid_toml() {
3466	let src_dir = tempfile::tempdir().unwrap();
3467	let custom_dir = tempfile::tempdir().unwrap();
3468	let src = src_dir.path().join("bad.toml");
3469	fs::write(&src, "this is not [valid toml [[[").unwrap();
3470	assert!(import_theme(&src, custom_dir.path()).is_err());
3471	}
3472
3473	#[test]
3474	fn delete_theme_removes_and_guards() {
3475	let custom = tempfile::tempdir().unwrap();
3476	let path = custom.path().join("doomed.toml");
3477	fs::write(&path, "[surface]\npage = \"#000\"\n").unwrap();
3478	delete_theme(custom.path(), "doomed").unwrap();
3479	assert!(!path.exists());
3480	assert!(delete_theme(custom.path(), "../etc/passwd").is_err());
3481	assert!(delete_theme(custom.path(), "ghost").is_err());
3482	}
3483
3484	#[test]
3485	fn export_theme_copies_file() {
3486	let src_dir = tempfile::tempdir().unwrap();
3487	let dest_dir = tempfile::tempdir().unwrap();
3488	let content = "[meta]\nname = \"E\"\n[surface]\npage = \"#ffffff\"\n";
3489	fs::write(src_dir.path().join("e.toml"), content).unwrap();
3490	let dirs = vec![(src_dir.path().to_path_buf(), false)];
3491	let dest = dest_dir.path().join("out.toml");
3492	export_theme(&dirs, "e", &dest).unwrap();
3493	assert_eq!(fs::read_to_string(&dest).unwrap(), content);
3494	assert!(export_theme(&dirs, "missing", &dest).is_err());
3495	}
3496
3497	#[test]
3498	fn load_theme_preview_returns_role_swatches() {
3499	let dir = tempfile::tempdir().unwrap();
3500	fs::write(dir.path().join("nord.toml"), nord_toml()).unwrap();
3501	let dirs = vec![(dir.path().to_path_buf(), false)];
3502	let p = load_theme_preview(&dirs, "nord").unwrap();
3503	assert_eq!(p.background.as_deref(), Some("#2e3440")); // surface.page
3504	assert_eq!(p.foreground.as_deref(), Some("#d8dee9")); // content.primary
3505	assert_eq!(p.accent.as_deref(), Some("#81a1c1")); // action.primary
3506	assert_eq!(p.border.as_deref(), Some("#4c566a")); // line.border
3507	}
3508
3509	#[test]
3510	fn bundled_themes_dir_resolves_to_shipped_themes() {
3511	// The crate ships its themes, so this must resolve in-tree and the
3512	// Akari defaults the console falls back to must be present.
3513	let dir = bundled_themes_dir().expect("makeover ships a themes/ directory");
3514	assert!(dir.join("akari-dawn.toml").is_file());
3515	assert!(dir.join("akari-night.toml").is_file());
3516	}
3517
3518	#[test]
3519	fn every_theme_is_accounted_for_in_third_party_notices() {
3520	// Attribution is a redistribution obligation, not a nicety: adding a
3521	// theme without a notice entry silently ships someone's work
3522	// uncredited. Fail here instead.
3523	let notices = std::fs::read_to_string(
3524	Path::new(env!("CARGO_MANIFEST_DIR")).join("THIRD-PARTY-NOTICES.md"),
3525	)
3526	.expect("THIRD-PARTY-NOTICES.md must exist");
3527	let missing: Vec<&str> = embedded_themes()
3528	.map(\|(id, _)\| id)
3529	.filter(\|id\| !notices.contains(*id))
3530	.collect();
3531	assert!(
3532	missing.is_empty(),
3533	"themes missing from THIRD-PARTY-NOTICES.md: {missing:?}"
3534	);
3535	}
3536
3537	#[test]
3538	fn adapted_themes_carry_inline_attribution() {
3539	// Each adapted file must name its upstream in-file, so the credit
3540	// survives someone copying a single .toml out of the crate.
3541	const ORIGINALS: [&str; 5] = [
3542	"makenotwork",
3543	"goingson",
3544	"audiofiles",
3545	"high-contrast",
3546	"neobrute",
3547	];
3548	for (id, source) in embedded_themes() {
3549	if ORIGINALS.contains(&id) {
3550	continue;
3551	}
3552	assert!(
3553	source.contains("adapted from"),
3554	"adapted theme `{id}` is missing its inline attribution header"
3555	);
3556	}
3557	}
3558
3559	#[test]
3560	fn embedded_themes_match_the_directory() {
3561	// The embedded copy and themes/ are two views of one source. If they
3562	// ever disagree, path-based and path-free consumers render different
3563	// theme sets, which is exactly the drift shipping the data was meant
3564	// to prevent.
3565	let dir = bundled_themes_dir().unwrap();
3566	let mut on_disk: Vec<String> = std::fs::read_dir(&dir)
3567	.unwrap()
3568	.filter_map(\|e\| {
3569	let path = e.ok()?.path();
3570	if path.extension()? != "toml" {
3571	return None;
3572	}
3573	Some(path.file_stem()?.to_str()?.to_string())
3574	})
3575	.collect();
3576	let mut embedded: Vec<String> = embedded_themes().map(\|(id, _)\| id.to_string()).collect();
3577	on_disk.sort();
3578	embedded.sort();
3579	assert_eq!(embedded, on_disk, "embedded theme set drifted from themes/");
3580	}
3581
3582	#[test]
3583	fn every_embedded_theme_parses() {
3584	// Guards the path-free consumers (MNW server, the Tauri build steps)
3585	// the same way every_shipped_theme_loads guards the path-based ones.
3586	let mut count = 0;
3587	for (id, source) in embedded_themes() {
3588	parse_theme_str(id, source, false)
3589	.unwrap_or_else(\|e\| panic!("embedded theme `{id}` failed to parse: {e}"));
3590	count += 1;
3591	}
3592	assert!(count >= 30, "expected the full theme set, got {count}");
3593	}
3594
3595	#[test]
3596	fn every_shipped_theme_loads() {
3597	// Guards the data, not just the loader: a malformed or truncated
3598	// .toml in themes/ is a shipping bug, and it should fail here rather
3599	// than at a user's first launch.
3600	let dir = bundled_themes_dir().unwrap();
3601	let dirs = vec![(dir.clone(), false)];
3602	let themes = list_themes_from_dirs(&dirs);
3603	assert!(
3604	themes.len() >= 30,
3605	"expected the full theme set, got {}",
3606	themes.len()
3607	);
3608	for meta in &themes {
3609	load_theme(&dirs, &meta.id)
3610	.unwrap_or_else(\|e\| panic!("shipped theme `{}` failed to load: {e}", meta.id));
3611	}
3612	}
3613	}
3614