//! The face shop bundles, cut at build time by `quasi-type`.
//!
//! One crate rather than an `include_bytes!` in each caller: the binary and two
//! test suites all want the same bytes, and cutting it three times would
//! download the base three times and leave three places to state the weight.

/// Quasi Mono, the house monospace face.
///
/// Variable on `wght` 200-800 in one file. **At rest it is `wght` 200**, since
/// a cut keeps its base's default instance and Atkinson Hyperlegible Mono's is
/// ExtraLight, so anything rendering it names a weight — see [`WEIGHT`].
pub static FACE: &[u8] = include_bytes!(env!("SHOP_FONT_FACE"));

/// The base's licence text. OFL 1.1 requires it to travel with a modified
/// build, so it travels inside the binary and `shop --license` prints it.
pub static LICENSE: &str = include_str!(env!("SHOP_FONT_LICENSE"));

/// The family name the face carries, for a fontconfig query or a log line.
pub const FAMILY: &str = env!("SHOP_FONT_FAMILY");

/// The style of the face's default instance, which is what `fc-match` and a
/// naive loader both report. `ExtraLight` today.
pub const DEFAULT_STYLE: &str = env!("SHOP_FONT_STYLE");

/// The weight the face opens at, which is its base's default instance.
///
/// Stated so the trap is a number in the source rather than a sentence in a
/// comment: it is 200 today, and nothing should draw at it.
pub const DEFAULT_WEIGHT: f32 = {
    // `parse` is not const, and the value comes from the build script as a
    // string. Two digits of it are all that is ever needed.
    match env!("SHOP_FONT_DEFAULT_WEIGHT").as_bytes() {
        [b'2', b'0', b'0', ..] => 200.0,
        [b'4', b'0', b'0', ..] => 400.0,
        _ => f32::NAN,
    }
};

/// The weight a terminal draws body text at.
///
/// Named rather than inherited. The face's own default is the light end of its
/// axis, and a terminal that took it would draw every prompt in ExtraLight.
pub const WEIGHT: f32 = 400.0;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn the_face_is_a_truetype_file_carrying_an_axis() {
        assert_eq!(&FACE[0..4], &[0x00, 0x01, 0x00, 0x00], "not an sfnt");
        let tags: Vec<&[u8]> = (0..u16::from_be_bytes([FACE[4], FACE[5]]) as usize)
            .map(|i| &FACE[12 + 16 * i..16 + 16 * i])
            .collect();
        for wanted in [b"fvar", b"gvar", b"cmap", b"glyf"] {
            assert!(
                tags.contains(&&wanted[..]),
                "{} is missing, so this is not a cut variable face",
                String::from_utf8_lossy(wanted)
            );
        }
    }

    #[test]
    fn the_licence_travels_with_it() {
        assert!(LICENSE.contains("SIL OPEN FONT LICENSE"));
    }

    /// The trap this crate exists to make impossible to forget.
    #[test]
    fn the_faces_own_default_is_not_the_weight_we_draw_at() {
        assert_eq!(DEFAULT_STYLE, "ExtraLight");
        assert!(
            (WEIGHT - DEFAULT_WEIGHT).abs() > f32::EPSILON,
            "the weight shop draws at is the file's own default, so naming it bought nothing"
        );
    }
}