<?php

use Illuminate\Support\Facades\File;
use Illuminate\Support\Str;

function packageCss(string $path = ''): string
{
    return __DIR__.'/../../resources/css'.($path === '' ? '' : '/'.$path);
}

/**
 * The custom properties one selector's block declares.
 *
 * @return array<string, string>
 */
function declarations(string $css, string $selector): array
{
    preg_match_all('/(--[\w-]+):\s*([^;]+);/', Str::of($css)->after($selector)->before('}')->toString(), $matches);

    return array_combine($matches[1], $matches[2]);
}

/**
 * M3's 15 type styles, in the order type.css declares them.
 *
 * @return list<string>
 */
function typeStyles(): array
{
    return [
        'display-lg', 'display-md', 'display-sm',
        'headline-lg', 'headline-md', 'headline-sm',
        'title-lg', 'title-md', 'title-sm',
        'body-lg', 'body-md', 'body-sm',
        'label-lg', 'label-md', 'label-sm',
    ];
}

/**
 * The body of every `@utility type-…` block of type.css, keyed by utility name.
 *
 * @return array<string, string>
 */
function typeUtilities(): array
{
    preg_match_all('/@utility (type-[\w-]+) \{\n(.*?)\n\}/s', File::get(packageCss('tokens/type.css')), $matches, PREG_SET_ORDER);

    return array_combine(array_column($matches, 1), array_column($matches, 2));
}

it('ships a default scheme that declares every role in both themes', function () {
    $scheme = json_decode(File::get(packageCss('tokens/scheme.json')), true);
    $css = File::get(packageCss('tokens/scheme.css'));

    $light = declarations($css, "[data-theme='light']");
    $dark = declarations($css, "[data-theme='dark']");

    expect(array_keys($light))->toEqual(array_keys($dark))
        ->and(count($light))->toBe(count($scheme['light']))
        ->and(Str::of($css)->after("[data-theme='light']")->before('}')->toString())->toContain('color-scheme: light;')
        ->and(Str::of($css)->after("[data-theme='dark']")->before('}')->toString())->toContain('color-scheme: dark;');

    foreach ($scheme['light'] as $role => $hex) {
        expect($light["--md-sys-color-{$role}"])->toBe($hex)
            ->and($dark["--md-sys-color-{$role}"])->toBe($scheme['dark'][$role]);
    }
});

it('ships M3\'s medium and high contrast levels beside the standard one', function () {
    $scheme = json_decode(File::get(packageCss('tokens/scheme.json')), true);
    $css = File::get(packageCss('tokens/scheme.css'));

    foreach (['medium', 'high'] as $level) {
        foreach (['light', 'dark'] as $theme) {
            $declared = declarations($css, "[data-contrast='{$level}'] [data-theme='{$theme}'] {");

            expect(array_keys($declared))->toEqual(array_map(fn (string $role): string => "--md-sys-color-{$role}", array_keys($scheme['light'])));

            foreach ($scheme['contrast'][$level][$theme] as $role => $hex) {
                expect($declared["--md-sys-color-{$role}"])->toBe($hex);
            }
        }
    }
});

it('turns every role into a Tailwind colour', function () {
    $roles = array_keys(json_decode(File::get(packageCss('tokens/scheme.json')), true)['light']);
    $theme = File::get(packageCss('tokens/theme.css'));

    foreach ($roles as $role) {
        expect($theme)->toContain("--color-{$role}: var(--md-sys-color-{$role});");
    }
});

it('resolves colour utilities on the element, so a nested data-theme repaints them', function () {
    $theme = File::get(packageCss('tokens/theme.css'));

    preg_match_all('/@theme inline \{(.*?)\}/s', $theme, $inline);

    expect(implode("\n", $inline[1]))
        ->toContain('--color-primary: var(--md-sys-color-primary);')
        ->toContain('--color-body: var(--md-sys-color-on-surface-variant);')
        ->not->toMatch('/--[\w-]+:\s*#/');
});

it('leaves the choice of theme and of contrast to the head script, never to a media query', function () {
    foreach (File::allFiles(packageCss()) as $file) {
        expect($file->getContents())
            ->not->toContain('prefers-color-scheme')
            ->not->toContain('prefers-contrast');
    }
});

it('reads every safe-area inset through a variable that can replace it', function () {
    $files = collect([packageCss(), __DIR__.'/../../resources/views', __DIR__.'/../../resources/js'])
        ->flatMap(fn (string $path): array => File::allFiles($path));

    $insets = 0;

    foreach ($files as $file) {
        preg_match_all('/env\(safe-area-inset-(top|bottom|left|right)\)/', $file->getContents(), $matches, PREG_OFFSET_CAPTURE);

        foreach ($matches[1] as [$side, $offset]) {
            $insets++;

            expect(substr($file->getContents(), 0, $offset - strlen('env(safe-area-inset-')))
                ->toMatch("/var\\(--material-safe-{$side},\\s?$/", "{$file->getRelativePathname()} reads safe-area-inset-{$side} directly");
        }
    }

    expect($insets)->toBeGreaterThan(10)
        ->and(File::get(packageCss('components/app-bar.css')))->toContain('padding-top: var(--material-safe-top, env(safe-area-inset-top));');
});

it('makes every motion token instant under reduced motion, in both schemes', function () {
    $motion = File::get(packageCss('tokens/motion.css'));
    $reduced = Str::of($motion)->after('prefers-reduced-motion: reduce')->toString();

    preg_match_all('/(--md-sys-motion-[\w-]*duration[\w-]*):/', Str::before($motion, '@media'), $durations);

    expect($durations[1])->not->toBeEmpty()
        // The Standard scheme sets the same variables on a selector of its own, so :root alone
        // would not reach it: the block has to name both.
        ->and($reduced)->toMatch('/:root,\s*\[data-motion="standard"\] \{/');

    foreach ($durations[1] as $duration) {
        expect($reduced)->toContain("{$duration}: 0ms;");
    }
});

it('resets the roundness axis on every regular type style, so emphasis stays one element', function () {
    $utilities = typeUtilities();

    expect(array_keys($utilities))->toHaveCount(30);

    foreach (typeStyles() as $style) {
        expect($utilities)->toHaveKeys(["type-{$style}", "type-emphasized-{$style}"])
            // font-variation-settings inherits: without the reset, body copy inside an
            // emphasized heading would stay fully rounded.
            ->and($utilities["type-{$style}"])->toContain('font-variation-settings: normal;')
            ->and($utilities["type-emphasized-{$style}"])->toContain('font-variation-settings: "ROND" 100;');
    }
});

it('gives every emphasized type style its own tracking, as Compose does', function () {
    $tokens = declarations(File::get(packageCss('tokens/type.css')), ':root');
    $utilities = typeUtilities();

    foreach (typeStyles() as $style) {
        expect($tokens)->toHaveKey("--md-sys-typescale-emphasized-{$style}-tracking")
            ->and($utilities["type-{$style}"])->toContain("letter-spacing: var(--md-sys-typescale-{$style}-tracking);")
            ->and($utilities["type-emphasized-{$style}"])->toContain("letter-spacing: var(--md-sys-typescale-emphasized-{$style}-tracking);");
    }

    // TypeScaleTokens.kt as sp / 16, for the five styles where emphasized parts from baseline.
    expect($tokens)->toMatchArray([
        '--md-sys-typescale-display-lg-tracking' => '-0.0125rem',
        '--md-sys-typescale-emphasized-display-lg-tracking' => '0rem',
        '--md-sys-typescale-title-md-tracking' => '0.0125rem',
        '--md-sys-typescale-emphasized-title-md-tracking' => '0.009375rem',
        '--md-sys-typescale-body-lg-tracking' => '0.03125rem',
        '--md-sys-typescale-emphasized-body-lg-tracking' => '0.009375rem',
        '--md-sys-typescale-body-md-tracking' => '0.0125rem',
        '--md-sys-typescale-emphasized-body-md-tracking' => '0.015625rem',
        '--md-sys-typescale-label-md-tracking' => '0.03125rem',
        '--md-sys-typescale-emphasized-label-md-tracking' => '0.03125rem',
    ]);
});

it('reads every spring over the duration M3 publishes for the web', function () {
    $expressive = declarations(File::get(packageCss('tokens/motion.css')), ':root');

    // docs/reference/m3/styles.md § Motion, "Web curve equivalents for springs".
    $durations = [
        'spatial-fast' => '350ms', 'spatial-default' => '500ms', 'spatial-slow' => '650ms',
        'effects-fast' => '150ms', 'effects-default' => '200ms', 'effects-slow' => '300ms',
    ];

    foreach ($durations as $spring => $duration) {
        expect($expressive["--md-sys-motion-{$spring}-duration"])->toBe($duration)
            // 49 sampled points, starting at rest and landing exactly on the target.
            ->and($expressive["--md-sys-motion-{$spring}"])->toStartWith('linear(0, ')->toEndWith(', 1)')
            ->and(explode(', ', $expressive["--md-sys-motion-{$spring}"]))->toHaveCount(49);
    }
});

it('swaps only the spatial springs for the Standard motion scheme', function () {
    $motion = File::get(packageCss('tokens/motion.css'));
    $expressive = declarations($motion, ':root');
    $standard = declarations($motion, '[data-motion="standard"] {');

    // Both schemes share the effects springs, so the block carries the three spatial pairs only.
    expect(array_keys($standard))->toBe([
        '--md-sys-motion-spatial-fast', '--md-sys-motion-spatial-fast-duration',
        '--md-sys-motion-spatial-default', '--md-sys-motion-spatial-default-duration',
        '--md-sys-motion-spatial-slow', '--md-sys-motion-spatial-slow-duration',
    ]);

    foreach (['fast' => '350ms', 'default' => '500ms', 'slow' => '750ms'] as $speed => $duration) {
        expect($standard["--md-sys-motion-spatial-{$speed}-duration"])->toBe($duration)
            ->and($standard["--md-sys-motion-spatial-{$speed}"])->toStartWith('linear(0, ')
            ->not->toBe($expressive["--md-sys-motion-spatial-{$speed}"]);
    }
});