<?php
/**
 * serve_media.php - Serves media files with proper headers for streaming
 */

// Get the requested file path
$requestedFile = isset($_GET['file']) ? $_GET['file'] : '';

if (empty($requestedFile)) {
    header('HTTP/1.1 400 Bad Request');
    echo 'No file specified';
    exit;
}

// IMPORTANT: Set base directory to where media actually lives
// Using home directory + GDrive instead of __DIR__
$homeDir = getenv('HOME') ?: (getenv('USERPROFILE') ?: '/home/' . get_current_user());
$baseDir = $homeDir . '/GDrive';

// Construct full path
$filePath = $baseDir . DIRECTORY_SEPARATOR . $requestedFile;

// Security: Prevent directory traversal attacks
$realBase = realpath($baseDir);
$realFile = realpath($filePath);

// Additional debug info (remove in production)
if ($realFile === false) {
    header('HTTP/1.1 404 Not Found');
    echo 'File not found. Debug info:' . "\n";
    echo 'Base dir: ' . $baseDir . "\n";
    echo 'Requested: ' . $requestedFile . "\n";
    echo 'Full path: ' . $filePath . "\n";
    exit;
}

if (strpos($realFile, $realBase) !== 0) {
    header('HTTP/1.1 403 Forbidden');
    echo 'Access denied - path outside base directory';
    exit;
}

// Check if file exists
if (!file_exists($filePath) || !is_file($filePath)) {
    header('HTTP/1.1 404 Not Found');
    echo 'File not found';
    exit;
}

// Get file information
clearstatcache(true, $filePath); // Clear file stat cache
$fileSize = filesize($filePath);
$fileExtension = strtolower(pathinfo($filePath, PATHINFO_EXTENSION));

// Disable output buffering to prevent Content-Length mismatches
if (ob_get_level()) {
    ob_end_clean();
}

// Set content type based on extension
$mimeTypes = [
    // Video
    'mp4' => 'video/mp4',
    'mkv' => 'video/x-matroska',
    'avi' => 'video/x-msvideo',
    'mov' => 'video/quicktime',
    'wmv' => 'video/x-ms-wmv',
    'flv' => 'video/x-flv',
    'webm' => 'video/webm',
    'm4v' => 'video/x-m4v',
    // Audio
    'mp3' => 'audio/mpeg',
    'wav' => 'audio/wav',
    'ogg' => 'audio/ogg',
    'flac' => 'audio/flac',
    'm4a' => 'audio/mp4',
    'aac' => 'audio/aac',
    'wma' => 'audio/x-ms-wma',
    'opus' => 'audio/opus'
];

$contentType = isset($mimeTypes[$fileExtension]) ? $mimeTypes[$fileExtension] : 'application/octet-stream';

// Handle range requests for seeking
$range = isset($_SERVER['HTTP_RANGE']) ? $_SERVER['HTTP_RANGE'] : '';

if (!empty($range)) {
    // Parse range header
    list($unit, $range) = explode('=', $range, 2);
    
    if ($unit === 'bytes') {
        // Parse range values
        list($start, $end) = explode('-', $range, 2);
        $start = intval($start);
        $end = !empty($end) ? intval($end) : $fileSize - 1;
        
        // Validate range
        if ($start > $end || $start < 0 || $end >= $fileSize) {
            header('HTTP/1.1 416 Requested Range Not Satisfiable');
            header("Content-Range: bytes */$fileSize");
            exit;
        }
        
        $length = $end - $start + 1;
        
        // Set headers for partial content
        header('HTTP/1.1 206 Partial Content');
        header("Content-Range: bytes $start-$end/$fileSize");
        header("Content-Length: $length");
        header("Content-Type: $contentType");
        header('Accept-Ranges: bytes');
        
        // Open file and seek to start position
        $file = fopen($filePath, 'rb');
        if ($file === false) {
            header('HTTP/1.1 500 Internal Server Error');
            echo 'Failed to open file';
            exit;
        }
        
        fseek($file, $start);
        
        // Output the requested range
        $buffer = 8192; // 8KB chunks
        $bytesRemaining = $length;
        
        while ($bytesRemaining > 0 && !feof($file)) {
            $bytesToRead = min($buffer, $bytesRemaining);
            $data = fread($file, $bytesToRead);
            if ($data === false) {
                break;
            }
            echo $data;
            $bytesRemaining -= strlen($data);
            if (connection_aborted()) {
                break;
            }
        }
        
        fclose($file);
        exit; // Important: exit after streaming
    }
} else {
    // Normal full file response
    header('HTTP/1.1 200 OK');
    header("Content-Type: $contentType");
    header("Content-Length: $fileSize");
    header('Accept-Ranges: bytes');
    header('Cache-Control: public, max-age=3600');
    
    // Stream file in chunks to avoid memory issues
    $file = fopen($filePath, 'rb');
    if ($file === false) {
        header('HTTP/1.1 500 Internal Server Error');
        echo 'Failed to open file';
        exit;
    }
    
    $buffer = 8192; // 8KB chunks
    while (!feof($file) && !connection_aborted()) {
        echo fread($file, $buffer);
    }
    
    fclose($file);
    exit; // Important: exit after streaming
}
?>