<?php
/**
 * Get Session File API
 * Fetches a specific file from backend sessions and returns as base64
 * Used for importing backend files to projects
 */

// Suppress HTML error output
error_reporting(E_ALL);
ini_set('display_errors', 0);
ini_set('log_errors', 1);

header('Content-Type: application/json');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

// Handle OPTIONS preflight
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    http_response_code(200);
    exit;
}

try {
    // Get parameters
    $sessionId = $_GET['session_id'] ?? '';
    $fileType = $_GET['file_type'] ?? 'image'; // 'image' or 'video'
    $filename = $_GET['filename'] ?? '';

    // Validate parameters
    if (empty($sessionId)) {
        throw new Exception('Missing session_id parameter');
    }
    if (empty($filename)) {
        throw new Exception('Missing filename parameter');
    }
    if (!in_array($fileType, ['image', 'video'])) {
        throw new Exception('Invalid file_type parameter (must be "image" or "video")');
    }

    // Sanitize inputs to prevent directory traversal
    $sessionId = basename($sessionId);
    $filename = basename($filename);

    // Construct file path
    $uploadsDir = __DIR__ . '/uploads/sessions';
    $subDir = $fileType === 'image' ? 'images' : 'videos';
    $filePath = $uploadsDir . '/' . $sessionId . '/' . $subDir . '/' . $filename;

    // Check if file exists
    if (!file_exists($filePath)) {
        http_response_code(404);
        echo json_encode([
            'success' => false,
            'error' => 'File not found',
            'message' => 'The requested file does not exist or has been deleted'
        ]);
        exit;
    }

    // Check if file is still valid (not expired)
    $createdAt = filectime($filePath);
    $expiresAt = $createdAt + (24 * 3600);
    if (time() > $expiresAt) {
        http_response_code(410);
        echo json_encode([
            'success' => false,
            'error' => 'File expired',
            'message' => 'This file has expired and will be deleted soon'
        ]);
        exit;
    }

    // Read file
    $fileContent = file_get_contents($filePath);
    if ($fileContent === false) {
        throw new Exception('Failed to read file');
    }

    // Convert to base64
    $base64Data = base64_encode($fileContent);

    // Get MIME type from metadata if available
    $mimeType = $fileType === 'image' ? 'image/jpeg' : 'video/mp4';
    $metaPath = $filePath . '.meta';
    if (file_exists($metaPath)) {
        $metaContent = file_get_contents($metaPath);
        $meta = json_decode($metaContent, true);
        if ($meta && isset($meta['mime_type'])) {
            $mimeType = $meta['mime_type'];
        }
    }

    // Get file size info
    $fileSize = strlen($fileContent);

    echo json_encode([
        'success' => true,
        'data' => $base64Data,
        'filename' => $filename,
        'mime_type' => $mimeType,
        'file_type' => $fileType,
        'size_bytes' => $fileSize,
        'size_kb' => round($fileSize / 1024, 2),
        'size_mb' => round($fileSize / (1024 * 1024), 2),
        'created_at' => $createdAt,
        'expires_at' => $expiresAt,
        'time_remaining' => max(0, $expiresAt - time())
    ]);

} catch (Exception $e) {
    error_log("Error in get_session_file.php: " . $e->getMessage());
    http_response_code(500);
    echo json_encode([
        'success' => false,
        'error' => 'Failed to fetch file',
        'message' => $e->getMessage()
    ]);
}