cargo-rahti-native 0.0.1

//! The launcher icons a new shell starts with.
//!
//! They are embedded rather than generated, so what matters is that the set is
//! complete and that every file in it is the image format its name claims —
//! a bundler handed something else fails with a message about nothing.

use super::*;

/// The eight-byte signature every PNG starts with.
const PNG_MAGIC: &[u8] = &[0x89, b'P', b'N', b'G', 0x0d, 0x0a, 0x1a, 0x0a];

fn dimensions(png: &[u8]) -> (u32, u32) {
    // IHDR is always the first chunk, and its payload starts at byte 16.
    assert_eq!(&png[..8], PNG_MAGIC, "not a PNG");
    assert_eq!(&png[12..16], b"IHDR", "IHDR is not the first chunk");
    (
        u32::from_be_bytes(png[16..20].try_into().unwrap()),
        u32::from_be_bytes(png[20..24].try_into().unwrap()),
    )
}

#[test]
fn every_size_a_bundler_looks_for_is_present_and_the_right_size() {
    // `bundle.icon` in the generated tauri.conf.json names the first three;
    // the Windows executable carries the `.ico`.
    for (name, expected) in [
        ("32x32.png", 32),
        ("128x128.png", 128),
        ("128x128@2x.png", 256),
        ("icon.png", 512),
    ] {
        let icon = DESKTOP
            .iter()
            .find(|i| i.path == name)
            .unwrap_or_else(|| panic!("{name} is missing"));
        let (width, height) = dimensions(icon.bytes);
        assert_eq!((width, height), (expected, expected), "{name}");
    }
}

#[test]
fn the_windows_executable_icon_is_an_ico() {
    let ico = DESKTOP
        .iter()
        .find(|i| i.path == "icon.ico")
        .expect("icon.ico is missing");
    // Reserved zero, then type 1 (icon rather than cursor).
    assert_eq!(&ico.bytes[..4], &[0, 0, 1, 0], "not an ICO");
    let images = u16::from_le_bytes(ico.bytes[4..6].try_into().unwrap());
    assert!(images > 0, "an ICO with no images in it");
}

#[test]
fn every_android_density_has_its_three_icons() {
    // Miss one and that density falls back to the project template's own,
    // which is the failure the whole embedded set exists to prevent.
    for density in ["mdpi", "hdpi", "xhdpi", "xxhdpi", "xxxhdpi"] {
        for name in ["ic_launcher", "ic_launcher_round", "ic_launcher_foreground"] {
            let path = format!("android/mipmap-{density}/{name}.png");
            let icon = ANDROID
                .iter()
                .find(|i| i.path == path)
                .unwrap_or_else(|| panic!("{path} is missing"));
            let (width, height) = dimensions(icon.bytes);
            assert_eq!(width, height, "{path} is not square");
            assert!(width >= 48, "{path} is {width}px, too small for a launcher");
        }
    }
}

#[test]
fn the_adaptive_icon_and_its_background_are_present() {
    // Android 8 and later compose `ic_launcher_foreground` over the colour
    // named by this XML pair; without them an adaptive launcher shows the
    // legacy square instead.
    for path in [
        "android/mipmap-anydpi-v26/ic_launcher.xml",
        "android/values/ic_launcher_background.xml",
    ] {
        let icon = ANDROID
            .iter()
            .find(|i| i.path == path)
            .unwrap_or_else(|| panic!("{path} is missing"));
        let text = String::from_utf8_lossy(icon.bytes);
        assert!(text.contains("<?xml"), "{path} is not XML");
    }
}

#[test]
fn a_density_climbs_with_its_name() {
    // mdpi through xxxhdpi is 1x to 4x. Out-of-order files would install and
    // look wrong only on some screens, which is the worst way to be wrong.
    let mut last = 0;
    for density in ["mdpi", "hdpi", "xhdpi", "xxhdpi", "xxxhdpi"] {
        let path = format!("android/mipmap-{density}/ic_launcher.png");
        let icon = ANDROID.iter().find(|i| i.path == path).unwrap();
        let (width, _) = dimensions(icon.bytes);
        assert!(
            width > last,
            "{density} is not larger than the density below"
        );
        last = width;
    }
}

#[test]
fn every_embedded_icon_has_bytes_and_a_relative_path() {
    for icon in all() {
        assert!(!icon.bytes.is_empty(), "{} is empty", icon.path);
        assert!(
            !icon.path.starts_with('/') && !icon.path.contains(".."),
            "{} is not a path inside native/icons/",
            icon.path
        );
        // `/` separators: these become directories on Windows too.
        assert!(!icon.path.contains('\\'), "{} uses a backslash", icon.path);
    }
}

#[test]
fn the_desktop_and_android_sets_do_not_overlap() {
    for desktop in DESKTOP {
        assert!(
            !ANDROID.iter().any(|a| a.path == desktop.path),
            "{} is in both sets",
            desktop.path
        );
    }
    assert_eq!(all().count(), DESKTOP.len() + ANDROID.len());
}