livewire-material/tests/Support/ComponentStylesheet.php

<?php

namespace NoNameWeb\LivewireMaterial\Tests\Support;

use RuntimeException;

/**
 * A component stylesheet (resources/css/components/<name>.css), read the way a render test asks
 * about it: its imports, its layer blocks, and the declarations of a rule by its selector.
 *
 * Nesting is resolved as the browser resolves it — `&` stands for the parent selector, and a
 * nested selector without `&` is a descendant of it — so a test names the selector the rule
 * applies to (`[data-md-button]:focus-visible`), not how the file happens to nest it. At-rules
 * (`@media`, `@starting-style`, `@supports`) are kept beside the selector they wrap.
 */
final class ComponentStylesheet
{
    /** @var list<array{selector: string, at: list<string>, declarations: array<string, string>}> */
    private array $rules = [];

    /** @var list<string> */
    private array $statements = [];

    /** @var list<string> */
    private array $blocks = [];

    private function __construct(public readonly string $name, public readonly string $css)
    {
        $source = self::withoutComments($css);

        foreach (self::items($source) as $item) {
            if (isset($item['statement'])) {
                $this->statements[] = $item['statement'];

                continue;
            }

            $this->blocks[] = $item['prelude'];
            $this->collect($item['prelude'], $item['body'], null, []);
        }
    }

    public static function read(string $name): self
    {
        $path = self::path($name);

        if (! is_file($path)) {
            throw new RuntimeException("No stylesheet [{$name}].");
        }

        return new self($name, (string) file_get_contents($path));
    }

    public static function path(string $name): string
    {
        return dirname(__DIR__, 2)."/resources/css/components/{$name}.css";
    }

    /**
     * The statements before the first block, in order: the layer statement and the imports.
     *
     * @return list<string>
     */
    public function statements(): array
    {
        return $this->statements;
    }

    /**
     * The files this stylesheet imports, as written.
     *
     * @return list<string>
     */
    public function imports(): array
    {
        return array_values(array_filter(array_map(
            fn (string $statement): ?string => preg_match('/^@import\s+([\'"])(.+?)\1;$/', $statement, $match) === 1 ? $match[2] : null,
            $this->statements,
        )));
    }

    /**
     * The preludes of the top-level blocks.
     *
     * @return list<string>
     */
    public function blocks(): array
    {
        return $this->blocks;
    }

    /**
     * The declarations of every rule for this selector (and inside these at-rules, outermost
     * first), merged in source order.
     *
     * @param  list<string>  $at
     * @return array<string, string>
     */
    public function declarations(string $selector, array $at = []): array
    {
        $selector = self::normalise($selector);
        $at = array_map(self::normalise(...), $at);
        $found = false;
        $declarations = [];

        foreach ($this->rules as $rule) {
            if ($rule['selector'] === $selector && $rule['at'] === $at) {
                $found = true;
                $declarations = array_merge($declarations, $rule['declarations']);
            }
        }

        if (! $found) {
            throw new RuntimeException("{$this->name}.css has no rule [{$selector}]".($at === [] ? '' : ' inside ['.implode(' › ', $at).']').'.');
        }

        return $declarations;
    }

    public function has(string $selector, array $at = []): bool
    {
        try {
            $this->declarations($selector, $at);

            return true;
        } catch (RuntimeException) {
            return false;
        }
    }

    /**
     * Every media query the stylesheet writes.
     *
     * @return list<string>
     */
    public function mediaQueries(): array
    {
        preg_match_all('/@media\s*([^{]+)\{/', self::withoutComments($this->css), $matches);

        return array_map(fn (string $query): string => self::normalise($query), $matches[1]);
    }

    /**
     * @param  list<string>  $at
     */
    private function collect(string $prelude, string $body, ?string $parent, array $at): void
    {
        if (str_starts_with($prelude, '@layer')) {
            foreach (self::items($body) as $item) {
                if (isset($item['prelude'])) {
                    $this->collect($item['prelude'], $item['body'], $parent, $at);
                }
            }

            return;
        }

        if (str_starts_with($prelude, '@')) {
            $at[] = self::normalise($prelude);
            $selector = $parent;
        } else {
            $selector = $parent === null ? self::normalise($prelude) : self::nest($parent, $prelude);
        }

        $declarations = [];

        foreach (self::items($body, true) as $item) {
            if (isset($item['prelude'])) {
                $this->collect($item['prelude'], $item['body'], $selector, $at);
            } elseif (isset($item['statement']) && str_contains($item['statement'], ':') && $selector !== null) {
                [$property, $value] = explode(':', rtrim($item['statement'], ';'), 2);
                $declarations[trim($property)] = self::normalise($value);
            }
        }

        if ($selector !== null && $declarations !== []) {
            $this->rules[] = ['selector' => $selector, 'at' => $at, 'declarations' => $declarations];
        }
    }

    private static function nest(string $parent, string $child): string
    {
        $parents = self::split($parent);

        return implode(', ', array_merge(...array_map(
            fn (string $each): array => array_map(
                fn (string $part): string => str_contains($part, '&') ? str_replace('&', $each, $part) : "{$each} {$part}",
                self::split($child),
            ),
            $parents,
        )));
    }

    /**
     * A selector list split at its top-level commas.
     *
     * @return list<string>
     */
    private static function split(string $selector): array
    {
        $parts = [];
        $depth = 0;
        $current = '';

        foreach (str_split(self::normalise($selector)) as $char) {
            $depth += match ($char) {
                '(', '[' => 1,
                ')', ']' => -1,
                default => 0,
            };

            if ($char === ',' && $depth === 0) {
                $parts[] = trim($current);
                $current = '';

                continue;
            }

            $current .= $char;
        }

        $parts[] = trim($current);

        return $parts;
    }

    private static function normalise(string $text): string
    {
        return trim((string) preg_replace('/\s+/', ' ', $text));
    }

    private static function withoutComments(string $css): string
    {
        return (string) preg_replace('~("(?:\\\\.|[^"\\\\])*"|\'(?:\\\\.|[^\'\\\\])*\')|/\*.*?\*/~s', '$1', $css);
    }

    /**
     * The statements and blocks at the top of a piece of CSS. Inside a rule a declaration may end
     * at the closing brace without a semicolon.
     *
     * @return list<array{statement: string}|array{prelude: string, body: string}>
     */
    private static function items(string $css, bool $declarations = false): array
    {
        $items = [];
        $start = 0;
        $depth = 0;
        $parens = 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 === '(') {
                $parens++;
            } elseif ($char === ')') {
                $parens--;
            } elseif ($char === '{') {
                if ($depth++ === 0) {
                    $opening = $i;
                }
            } elseif ($char === '}' && --$depth === 0) {
                $items[] = [
                    'prelude' => self::normalise(substr($css, $start, $opening - $start)),
                    'body' => substr($css, $opening + 1, $i - $opening - 1),
                ];
                $start = $i + 1;
            } elseif ($char === ';' && $depth === 0 && $parens === 0) {
                $items[] = ['statement' => self::normalise(substr($css, $start, $i - $start)).';'];
                $start = $i + 1;
            }
        }

        $rest = trim(substr($css, $start));

        if ($rest !== '') {
            if (! $declarations) {
                throw new RuntimeException('The stylesheet ends inside an unclosed rule.');
            }

            $items[] = ['statement' => self::normalise($rest).';'];
        }

        return $items;
    }
}