<?php

declare(strict_types = 1);

namespace KTXC\Http\Response;

/**
 * Simple file response that reads a file from disk and serves it.
 *
 * Only supports sending full file contents (no range / streaming for now).
 */
class FileResponse extends Response
{
    private string $filePath;

    public function __construct(string $filePath, int $status = 200, array $headers = [])
    {
        if (!is_file($filePath) || !is_readable($filePath)) {
            throw new \InvalidArgumentException(sprintf('FileResponse: file not found or not readable: %s', $filePath));
        }

        $this->filePath = $filePath;

        // Determine content type (very small helper; rely on common extensions)
        $mime = self::guessMimeType($filePath) ?? 'application/octet-stream';
        $headers['Content-Type'] = $headers['Content-Type'] ?? $mime;
        $headers['Content-Length'] = (string) filesize($filePath);
        $headers['Last-Modified'] = gmdate('D, d M Y H:i:s', filemtime($filePath)) . ' GMT';
        $headers['Cache-Control'] = $headers['Cache-Control'] ?? 'public, max-age=60';

        parent::__construct('', $status, $headers);

        // Defer reading file until sendContent to avoid memory usage.
    }

    public function getFilePath(): string
    {
        return $this->filePath;
    }

    public function sendContent(): static
    {
        // Output file contents directly
        readfile($this->filePath);
        return $this;
    }

    private static function guessMimeType(string $filePath): ?string
    {
        $ext = strtolower(pathinfo($filePath, PATHINFO_EXTENSION));
        return match ($ext) {
            'html', 'htm' => 'text/html; charset=UTF-8',
            'css' => 'text/css; charset=UTF-8',
            'js' => 'application/javascript; charset=UTF-8',
            'json' => 'application/json; charset=UTF-8',
            'png' => 'image/png',
            'jpg', 'jpeg' => 'image/jpeg',
            'gif' => 'image/gif',
            'svg' => 'image/svg+xml',
            'txt' => 'text/plain; charset=UTF-8',
            'xml' => 'application/xml; charset=UTF-8',
            default => self::finfoMime($filePath),
        };
    }

    private static function finfoMime(string $filePath): ?string
    {
        if (function_exists('finfo_open')) {
            $f = finfo_open(FILEINFO_MIME_TYPE);
            if ($f) {
                $mime = finfo_file($f, $filePath) ?: null;
                finfo_close($f);
                return $mime;
            }
        }
        return null;
    }
}