<?php
declare(strict_types=1);

/**
 * The editor plugins in `data/plugins/`: one ES module per `.js` file. Whether one runs is written
 * in the project that is open, not here (#119) – the server hands out every plugin it has and knows
 * nothing about switches. The folder is still not served statically: a module is only ever handed
 * out by its bare file name, so no request can reach past it.
 */
final class PluginStore
{
    public function __construct(private readonly string $dir)
    {
    }

    /** A file name as it may be asked for: no path, no leading dot, `.js` at the end. */
    public static function isValidName(string $name): bool
    {
        return (bool) preg_match('/^[A-Za-z0-9][A-Za-z0-9._-]*\.js$/', $name);
    }

    /**
     * Sorted by file name, which is also the order the editor activates them in.
     *
     * @return list<array{file: string, bytes: int, updatedAt: int}>
     */
    public function list(): array
    {
        $files = is_dir($this->dir) ? scandir($this->dir) : [];
        $out = [];
        foreach ($files === false ? [] : $files as $file) {
            if ($this->exists($file)) {
                $path = "{$this->dir}/{$file}";
                $out[] = [
                    'file' => $file,
                    'bytes' => (int) filesize($path),
                    'updatedAt' => (int) filemtime($path),
                ];
            }
        }
        usort($out, static fn (array $a, array $b): int => strcmp($a['file'], $b['file']));
        return $out;
    }

    /** The module's source, or null when there is no such plugin. */
    public function read(string $file): ?string
    {
        if (!$this->exists($file)) {
            return null;
        }
        $source = file_get_contents("{$this->dir}/{$file}");
        return $source === false ? null : $source;
    }

    private function exists(string $file): bool
    {
        return self::isValidName($file) && is_file("{$this->dir}/{$file}");
    }
}