<?php

use Illuminate\Support\Facades\File;
use NoNameWeb\LivewireMaterial\Support\Layout;

/**
 * The package's stylesheets are plain CSS in `material.*` layers, with no Tailwind in them. Every
 * one opens with the same layer statement, so the order holds whichever file a bundler reaches
 * first; then plain imports (an `@import` cannot sit inside a layer block, and `layer()` on it
 * would nest the layer twice); then its own `@layer material.<x>` blocks. The only rules outside
 * a layer are foundation/hidden.css's two `!important` ones.
 *
 * Until the components leave Tailwind, the checks cover the foundation — foundation.css and every
 * file it imports, text.css included — and material.css and tailwind.css carry the rest.
 */
const MATERIAL_LAYER_STATEMENT = '@layer material.reset, material.tokens, material.base, material.layout, material.components, material.text, material.visibility;';

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

/**
 * A stylesheet without its comments; a quoted string keeps whatever it holds.
 */
function stylesheetWithoutComments(string $css): string
{
    return (string) preg_replace('~("(?:\\\\.|[^"\\\\])*"|\'(?:\\\\.|[^\'\\\\])*\')|/\*.*?\*/~s', '$1', $css);
}

/**
 * The top-level statements (`@layer …;`, `@import …;`) and blocks of a stylesheet, in order, with
 * whitespace collapsed in statements and preludes.
 *
 * @return list<array{statement: string}|array{prelude: string, body: string}>
 */
function stylesheetItems(string $css): array
{
    $css = stylesheetWithoutComments($css);
    $items = [];
    $start = 0;
    $depth = 0;
    $quote = null;
    $opening = 0;

    for ($i = 0, $length = strlen($css); $i < $length; $i++) {
        $char = $css[$i];

        if ($quote !== null) {
            if ($char === '\\') {
                $i++;
            } elseif ($char === $quote) {
                $quote = null;
            }

            continue;
        }

        if ($char === '"' || $char === "'") {
            $quote = $char;
        } elseif ($char === '{') {
            if ($depth++ === 0) {
                $opening = $i;
            }
        } elseif ($char === '}' && --$depth === 0) {
            $items[] = [
                'prelude' => (string) preg_replace('/\s+/', ' ', trim(substr($css, $start, $opening - $start))),
                'body' => substr($css, $opening + 1, $i - $opening - 1),
            ];
            $start = $i + 1;
        } elseif ($char === ';' && $depth === 0) {
            $items[] = ['statement' => preg_replace('/\s+/', ' ', trim(substr($css, $start, $i - $start))).';'];
            $start = $i + 1;
        }
    }

    expect(trim(substr($css, $start)))->toBe('', 'The stylesheet ends inside an unclosed rule.');

    return $items;
}

/**
 * The declarations of a flat block body, by property.
 *
 * @return array<string, string>
 */
function stylesheetDeclarations(string $body): array
{
    return collect(explode(';', $body))
        ->map(fn (string $declaration): string => trim($declaration))
        ->filter()
        ->mapWithKeys(fn (string $declaration): array => [trim(strstr($declaration, ':', true)) => trim(substr(strstr($declaration, ':'), 1))])
        ->all();
}

/**
 * The body of the first block with this prelude, at the top level or one layer block down.
 */
function stylesheetBlock(string $css, string $prelude): string
{
    foreach (stylesheetItems($css) as $item) {
        if (($item['prelude'] ?? null) === $prelude) {
            return $item['body'];
        }

        if (str_starts_with($item['prelude'] ?? '', '@layer ')) {
            foreach (stylesheetItems($item['body']) as $inner) {
                if (($inner['prelude'] ?? null) === $prelude) {
                    return $inner['body'];
                }
            }
        }
    }

    throw new RuntimeException("No block `{$prelude}`.");
}

/**
 * The paths a stylesheet imports, as written.
 *
 * @return list<string>
 */
function stylesheetImports(string $file): array
{
    return collect(stylesheetItems(File::get($file)))
        ->map(fn (array $item): ?string => preg_match('/^@import\s+([\'"])(.+?)\1/', $item['statement'] ?? '', $match) === 1 ? $match[2] : null)
        ->filter()
        ->values()
        ->all();
}

/**
 * A stylesheet and every stylesheet it reaches through `@import`, each once, in the order a
 * bundler meets them. `tailwindcss` itself is a package, not a file, and is left out.
 *
 * @return list<string>
 */
function stylesheetTree(string $entry): array
{
    $files = [];

    $visit = function (string $file) use (&$visit, &$files): void {
        $file = (string) realpath($file);

        if (in_array($file, $files, true)) {
            return;
        }

        $files[] = $file;

        foreach (stylesheetImports($file) as $import) {
            if (str_starts_with($import, '.')) {
                $visit(dirname($file).'/'.$import);
            }
        }
    };

    $visit($entry);

    return $files;
}

/**
 * The foundation: foundation.css and everything it imports.
 *
 * @return list<string>
 */
function foundationStylesheets(): array
{
    return stylesheetTree(stylesheetPath('foundation.css'));
}

function stylesheetName(string $file): string
{
    return substr($file, strlen(stylesheetPath()) + 1);
}

it('brings every foundation file and text.css into the foundation, and nothing of Tailwind', function () {
    $foundation = array_map(stylesheetName(...), foundationStylesheets());

    $parts = collect(File::files(stylesheetPath('foundation')))
        ->map(fn (SplFileInfo $file): string => 'foundation/'.$file->getFilename())
        ->push('foundation.css', 'text.css');

    expect($parts->diff($foundation)->values()->all())->toBe([])
        ->and(array_map(fn (string $import): string => basename($import), stylesheetImports(stylesheetPath('foundation.css'))))
        // In the order of their layers, the rules outside every layer beside the reset.
        ->toBe(['reset.css', 'hidden.css', 'tokens.css', 'base.css', 'interaction.css', 'text.css'])
        ->and($foundation)
        ->toContain('tokens/scheme.css', 'tokens/shape.css', 'tokens/elevation.css', 'tokens/motion.css', 'tokens/type.css', 'tokens/state.css', 'tokens/spacing.css', 'tokens/font.css')
        // The Tailwind half: the theme, the token utilities and the components still written for it.
        ->and(array_values(array_intersect($foundation, ['tokens/theme.css', 'tokens/utilities.css', 'tailwind.css', 'material.css'])))->toBe([])
        ->and(array_values(preg_grep('/^components\//', $foundation)))->toBe([]);
});

it('opens every foundation stylesheet with a header, the layer statement and plain imports', function () {
    foreach (foundationStylesheets() as $file) {
        $name = stylesheetName($file);
        $items = stylesheetItems(File::get($file));

        expect(File::get($file))->toStartWith('/*', "{$name} has no header comment")
            ->and($items[0]['statement'] ?? null)->toBe(MATERIAL_LAYER_STATEMENT, "{$name} does not open with the layer statement");

        $blocks = false;

        foreach (array_slice($items, 1) as $item) {
            if (isset($item['prelude'])) {
                $blocks = true;

                continue;
            }

            expect($blocks)->toBeFalse("{$name}: `{$item['statement']}` comes after a block")
                // A plain import: a quoted path and nothing after it — no layer(), supports() or media.
                ->and($item['statement'])->toMatch('/^@import ([\'"])\.{1,2}\/[\w.\/-]+\.css\1;$/', "{$name}: `{$item['statement']}` is not a plain import");
        }
    }
});

it('keeps every foundation rule inside its material layer, but the two that hide', function () {
    // Which layer each file writes into; tokens.css only imports.
    $layers = [
        'foundation.css' => null,
        'foundation/reset.css' => 'material.reset',
        'foundation/hidden.css' => null,
        'foundation/tokens.css' => null,
        'foundation/base.css' => 'material.base',
        'foundation/interaction.css' => 'material.base',
        'text.css' => 'material.text',
        'tokens/font.css' => 'material.base',
    ];

    $unlayered = [];
    $important = 0;

    foreach (foundationStylesheets() as $file) {
        $name = stylesheetName($file);
        $layer = array_key_exists($name, $layers) ? $layers[$name] : 'material.tokens';
        $important += substr_count(stylesheetWithoutComments(File::get($file)), '!important');

        foreach (stylesheetItems(File::get($file)) as $item) {
            if (! isset($item['prelude'])) {
                continue;
            }

            if (! str_starts_with($item['prelude'], '@layer ')) {
                $unlayered["{$name}: {$item['prelude']}"] = stylesheetDeclarations($item['body']);

                continue;
            }

            expect($item['prelude'])->toBe("@layer {$layer}", "{$name} writes into `{$item['prelude']}`")
                // A layer inside the block would become material.<x>.<y>, below the rest of <x>.
                ->and($item['body'])->not->toContain('@layer');
        }
    }

    expect($unlayered)->toBe([
        "foundation/hidden.css: [hidden]:where(:not([hidden='until-found']))" => ['display' => 'none !important'],
        'foundation/hidden.css: [x-cloak]' => ['display' => 'none !important'],
    ])->and($important)->toBe(2);
});

it('defines x-cloak once, where both the foundation and material.css reach it', function () {
    $definitions = collect(File::allFiles(stylesheetPath()))
        ->filter(fn (SplFileInfo $file): bool => $file->getExtension() === 'css')
        ->filter(fn (SplFileInfo $file): bool => str_contains(stylesheetWithoutComments($file->getContents()), '[x-cloak]'))
        ->map(fn (SplFileInfo $file): string => stylesheetName((string) $file->getRealPath()))
        ->values()
        ->all();

    $material = array_map(stylesheetName(...), stylesheetTree(stylesheetPath('material.css')));

    expect($definitions)->toBe(['foundation/hidden.css'])
        ->and($material)->toContain('foundation/hidden.css', 'tailwind.css')
        // Imported after Tailwind, the reset would sit in a layer above Tailwind's utilities.
        ->and(array_values(array_intersect($material, ['foundation.css', 'foundation/reset.css', 'foundation/base.css', 'foundation/interaction.css', 'text.css'])))->toBe([]);
});

it('writes no Tailwind directive in the foundation', function () {
    foreach (foundationStylesheets() as $file) {
        expect(stylesheetWithoutComments(File::get($file)))
            ->not->toMatch('/@(?:tailwind|theme|utility|variant|custom-variant|apply|source|config|plugin|reference)\b/', stylesheetName($file))
            ->not->toMatch('/--(?:theme|spacing|alpha)\(|\btheme\(|[\'"]tailwindcss[\'"]/', stylesheetName($file));
    }
});

it('writes a media query in the foundation only at M3\'s breakpoints, in px', function () {
    $queries = collect(foundationStylesheets())
        ->flatMap(function (string $file): array {
            preg_match_all('/@media\b([^{]*)\{/', stylesheetWithoutComments(File::get($file)), $matches);

            return array_map(fn (string $query): string => stylesheetName($file).': '.trim($query), $matches[1]);
        });

    // The foundation's own queries (hover, reduced motion) hold no width; the check is for what
    // lands here later.
    expect($queries)->not->toBeEmpty();

    foreach ($queries as $query) {
        preg_match_all('/(\d*\.?\d+)([a-z%]*)/i', substr($query, strpos($query, ': ') + 2), $lengths, PREG_SET_ORDER);

        foreach ($lengths as [, $number, $unit]) {
            expect($unit)->toBe('px', $query)
                ->and(in_array($number, ['600', '840', '1200', '1600'], true))->toBeTrue("{$query} is not at an M3 breakpoint");
        }
    }
});

it('declares M3\'s spacing scale as the reference gives it', function () {
    preg_match_all(
        '/^\|\s*\**space(\d+)\**\s*\|\s*\**([\d.]+)×\**\s*\|\s*\**(\d+)dp/m',
        File::get(__DIR__.'/../../docs/reference/m3/styles-supplement.md'),
        $rows,
        PREG_SET_ORDER,
    );

    $reference = collect($rows)->mapWithKeys(fn (array $row): array => ["--md-sys-measurement-space{$row[1]}" => "{$row[3]}px"])->all();
    $tokens = stylesheetDeclarations(stylesheetBlock(File::get(stylesheetPath('tokens/spacing.css')), ':root'));

    expect($reference)->toHaveCount(13)
        ->and($tokens)->toBe($reference);

    // space100 is the 8dp base unit and every name is its multiplier: space125 = 1.25 × 8.
    foreach ($rows as [, $name, $multiplier, $value]) {
        expect((float) $name / 100 * 8)->toBe((float) $value)
            ->and((float) $multiplier * 8)->toBe((float) $value);
    }
});

/**
 * The layout components' stylesheets: layout.css and everything it imports.
 *
 * @return list<string>
 */
function layoutStylesheets(): array
{
    return stylesheetTree(stylesheetPath('layout.css'));
}

it('imports a stylesheet for every layout component from layout.css, each beside its view', function () {
    $imports = stylesheetImports(stylesheetPath('layout.css'));
    $reached = array_map(stylesheetName(...), layoutStylesheets());

    $files = collect(File::files(stylesheetPath('layout')))->map(fn (SplFileInfo $file): string => $file->getBasename('.css'));

    // Two files are shared by the components rather than being one: the spacing props and the
    // visibility props.
    $components = $files->diff(['spacing', 'visibility'])->values();

    expect($components)->not->toBeEmpty()
        ->and($files->map(fn (string $name): string => "layout/{$name}.css")->diff($reached)->values()->all())->toBe([]);

    foreach ($components as $name) {
        expect(File::exists(__DIR__."/../../resources/views/components/{$name}.blade.php"))->toBeTrue("layout/{$name}.css has no component")
            ->and($imports)->toContain("./layout/{$name}.css");
    }
});

it('opens every layout stylesheet with a header, the layer statement and plain imports', function () {
    foreach (layoutStylesheets() as $file) {
        $name = stylesheetName($file);
        $items = stylesheetItems(File::get($file));

        expect(File::get($file))->toStartWith('/*', "{$name} has no header comment")
            ->and($items[0]['statement'] ?? null)->toBe(MATERIAL_LAYER_STATEMENT, "{$name} does not open with the layer statement");

        $blocks = false;

        foreach (array_slice($items, 1) as $item) {
            if (isset($item['prelude'])) {
                $blocks = true;

                continue;
            }

            expect($blocks)->toBeFalse("{$name}: `{$item['statement']}` comes after a block")
                ->and($item['statement'])->toMatch('/^@import ([\'"])\.{1,2}\/[\w.\/-]+\.css\1;$/', "{$name}: `{$item['statement']}` is not a plain import");
        }
    }
});

it('keeps every layout rule in material.layout, and the visibility props in material.visibility', function () {
    foreach (layoutStylesheets() as $file) {
        $name = stylesheetName($file);
        $css = File::get($file);
        $layer = match ($name) {
            'layout/visibility.css' => 'material.visibility',
            default => 'material.layout',
        };

        expect(stylesheetWithoutComments($css))->not->toContain('!important', $name);

        foreach (stylesheetItems($css) as $item) {
            if (! isset($item['prelude'])) {
                continue;
            }

            expect($item['prelude'])->toBe("@layer {$layer}", "{$name} writes outside `@layer {$layer}`")
                ->and($item['body'])->not->toContain('@layer');
        }
    }
});

it('writes no Tailwind in the layout stylesheets, and media queries only at M3\'s breakpoints, in px', function () {
    $queries = 0;

    foreach (layoutStylesheets() as $file) {
        $name = stylesheetName($file);
        $css = stylesheetWithoutComments(File::get($file));

        expect($css)
            ->not->toMatch('/@(?:tailwind|theme|utility|variant|custom-variant|apply|source|config|plugin|reference)\b/', $name)
            ->not->toMatch('/--(?:theme|spacing|alpha)\(|\btheme\(|[\'"]tailwindcss[\'"]/', $name);

        preg_match_all('/@media\b([^{]*)\{/', $css, $matches);

        foreach ($matches[1] as $query) {
            $queries++;

            expect(trim($query))->toMatch('/^\(width (?:<|>=) (?:600|840|1200|1600)px\)$/', "{$name}: `@media {$query}` is not an M3 breakpoint in px");
        }
    }

    expect($queries)->toBeGreaterThan(0);
});

it('gives every spacing token a gap and a padding, and the layout components read only those', function () {
    $tokens = array_map(
        fn (string $property): string => substr($property, strlen('--md-sys-measurement-')),
        array_keys(stylesheetDeclarations(stylesheetBlock(File::get(stylesheetPath('tokens/spacing.css')), ':root'))),
    );

    expect(Layout::SPACING)->toBe($tokens);

    $spacing = File::get(stylesheetPath('layout/spacing.css'));

    expect(stylesheetDeclarations(stylesheetBlock($spacing, "[data-md-gap='none']")))->toBe(['--md-gap' => '0px']);

    foreach ($tokens as $token) {
        expect(stylesheetDeclarations(stylesheetBlock($spacing, "[data-md-gap='{$token}']")))->toBe(['--md-gap' => "var(--md-sys-measurement-{$token})"])
            ->and(stylesheetDeclarations(stylesheetBlock($spacing, "[data-md-padding='{$token}']")))->toBe(['padding' => "var(--md-sys-measurement-{$token})"]);
    }

    expect(collect(stylesheetItems(stylesheetBlock($spacing, '@layer material.layout')))->pluck('prelude')->all())
        ->toHaveCount(1 + 2 * count($tokens));
});

it('hides an element below and from every breakpoint but compact, and nothing else', function () {
    $visibility = stylesheetBlock(File::get(stylesheetPath('layout/visibility.css')), '@layer material.visibility');

    $expected = [];

    foreach (['medium' => 600, 'expanded' => 840, 'large' => 1200, 'extra-large' => 1600] as $breakpoint => $width) {
        $expected["@media (width < {$width}px)"] = "[data-md-hide-below='{$breakpoint}']";
    }

    foreach (['medium' => 600, 'expanded' => 840, 'large' => 1200, 'extra-large' => 1600] as $breakpoint => $width) {
        $expected["@media (width >= {$width}px)"] = "[data-md-hide-from='{$breakpoint}']";
    }

    $actual = collect(stylesheetItems($visibility))->mapWithKeys(function (array $item): array {
        $rule = stylesheetItems($item['body'])[0];

        expect(stylesheetDeclarations($rule['body']))->toBe(['display' => 'none']);

        return [$item['prelude'] => $rule['prelude']];
    })->all();

    expect($actual)->toBe($expected);
});

it('gives every md-type class the declarations of its type utility', function () {
    preg_match_all('/@utility (type-[\w-]+) \{\n(.*?)\n\}/s', File::get(stylesheetPath('tokens/utilities.css')), $matches, PREG_SET_ORDER);

    $utilities = collect($matches)->mapWithKeys(fn (array $match): array => ["md-{$match[1]}" => stylesheetDeclarations($match[2])]);
    $text = File::get(stylesheetPath('text.css'));

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

    foreach ($utilities as $class => $declarations) {
        expect(stylesheetDeclarations(stylesheetBlock($text, ".{$class}")))->toBe($declarations, $class)
            ->and(array_keys($declarations))->toBe(['font', 'letter-spacing', 'font-variation-settings']);
    }
});

it('ships exactly the documented text classes, each ink an M3 role', function () {
    $text = File::get(stylesheetPath('text.css'));

    $styles = collect(['display', 'headline', 'title', 'body', 'label'])
        ->crossJoin(['lg', 'md', 'sm'])
        ->flatMap(fn (array $style): array => ["md-type-{$style[0]}-{$style[1]}", "md-type-emphasized-{$style[0]}-{$style[1]}"]);

    $inks = [
        'md-ink' => 'on-surface',
        'md-ink-variant' => 'on-surface-variant',
        'md-ink-quiet' => 'outline',
        'md-ink-primary' => 'primary',
        'md-ink-error' => 'error',
        'md-ink-success' => 'success',
        'md-ink-warning' => 'warning',
        'md-ink-info' => 'info',
        'md-ink-inverse' => 'inverse-on-surface',
    ];

    $rest = [
        'md-text-start' => ['text-align' => 'start'],
        'md-text-center' => ['text-align' => 'center'],
        'md-text-end' => ['text-align' => 'end'],
        'md-truncate' => ['overflow' => 'hidden', 'text-overflow' => 'ellipsis', 'white-space' => 'nowrap'],
        'md-line-clamp-2' => ['overflow' => 'hidden', 'display' => '-webkit-box', '-webkit-box-orient' => 'vertical', '-webkit-line-clamp' => '2'],
        'md-line-clamp-3' => ['overflow' => 'hidden', 'display' => '-webkit-box', '-webkit-box-orient' => 'vertical', '-webkit-line-clamp' => '3'],
        'md-nowrap' => ['white-space' => 'nowrap'],
        'md-tabular' => ['font-variant-numeric' => 'tabular-nums'],
        'md-visually-hidden' => [
            'position' => 'absolute', 'width' => '1px', 'height' => '1px', 'padding' => '0', 'margin' => '-1px',
            'overflow' => 'hidden', 'clip-path' => 'inset(50%)', 'white-space' => 'nowrap', 'border-width' => '0',
        ],
    ];

    $classes = collect(stylesheetItems(stylesheetBlock($text, '@layer material.text')))
        ->map(fn (array $item): string => $item['prelude'] ?? $item['statement'])
        ->all();

    expect($classes)->toBe($styles->merge(array_keys($inks))->merge(array_keys($rest))->map(fn (string $class): string => ".{$class}")->all());

    foreach ($inks as $class => $role) {
        expect(stylesheetDeclarations(stylesheetBlock($text, ".{$class}")))->toBe(['color' => "var(--md-sys-color-{$role})"]);
    }

    foreach ($rest as $class => $declarations) {
        expect(stylesheetDeclarations(stylesheetBlock($text, ".{$class}")))->toBe($declarations);
    }
});

it('draws the interaction classes as the utilities the Tailwind components still use', function () {
    $utilities = File::get(stylesheetPath('tokens/utilities.css'));
    $interaction = File::get(stylesheetPath('foundation/interaction.css'));

    $normalise = fn (string $body): string => trim((string) preg_replace('/\s+/', ' ', $body));

    foreach (['state-layer', 'focus-ring', 'touch-target', 'link'] as $name) {
        $class = stylesheetBlock($interaction, ".md-{$name}");

        expect($normalise(str_replace(
            // The two deliberate differences: the data-md-* hook beside the old one, and M3's 48
            // CSS pixels for the target where the utility reads 3rem.
            ['&:is([data-md-dragged], [data-dragged])', 'var(--md-sys-measurement-space600)'],
            ['&[data-dragged]', '3rem'],
            $class,
        )))->toBe($normalise(stylesheetBlock($utilities, "@utility {$name}")), $name);
    }

    expect(stylesheetBlock($interaction, '.md-state-layer'))->toContain('&:is([data-md-dragged], [data-dragged])::before')
        ->and(stylesheetBlock($interaction, '.md-touch-target'))->toContain('min-width: var(--md-sys-measurement-space600);');
});

it('declares the material layers in the Workbench before Tailwind\'s', function () {
    $app = stylesheetWithoutComments(File::get(__DIR__.'/../../workbench/resources/css/app.css'));

    $foundation = strpos($app, "@import '../../../resources/css/foundation.css';");
    $tailwind = strpos($app, "@import 'tailwindcss'");
    $components = strpos($app, "@import '../../../resources/css/tailwind.css';");

    expect($foundation)->toBeInt()
        ->and($tailwind)->toBeGreaterThan($foundation)
        ->and($components)->toBeGreaterThan($tailwind)
        // material.css would declare the tokens a second time.
        ->and($app)->not->toContain('material.css');
});