<?php
/**
 * get_files.php - Recursively scans media directories and returns file structure as JSON
 */
declare(strict_types=1);

require_once __DIR__ . '/auth.php';
require_auth(true);

header('Content-Type: application/json; charset=utf-8');

// Media type from query parameter (default: videos)
$type = $_GET['type'] ?? 'videos';

// Resolve base directory via MEDIA_ROOT
$mediaRoot = getenv('MEDIA_ROOT');
if ($mediaRoot === false || trim($mediaRoot) === '') {
    echo json_encode(['error' => 'MEDIA_ROOT is not set']);
    exit;
}

$baseDir = realpath(trim($mediaRoot));
if ($baseDir === false || !is_dir($baseDir)) {
    echo json_encode(['error' => 'MEDIA_ROOT base directory not found']);
    exit;
}

$directories = [
    'videos' => $baseDir . DIRECTORY_SEPARATOR . 'Videos',
    'music'  => $baseDir . DIRECTORY_SEPARATOR . 'Music',
];

// Extensions per tab (don’t mix)
$extensionsByType = [
    'videos' => ['mp4', 'mkv', 'avi', 'mov', 'wmv', 'flv', 'webm', 'm4v'],
    'music'  => ['mp3', 'wav', 'ogg', 'flac', 'm4a', 'aac', 'wma', 'opus'],
];

if (!isset($directories[$type])) {
    echo json_encode(['error' => 'Invalid media type']);
    exit;
}

$targetDir = $directories[$type];
$validExtensions = $extensionsByType[$type];

// Fail fast if dir missing
if (!is_dir($targetDir)) {
    echo json_encode(['error' => 'Directory not found']);
    exit;
}

/**
 * Recursively scan a directory and build a folder->(folders/files) structure.
 * Files are returned as paths relative to $baseDir.
 */
function scanDirectory(string $dir, string $baseDir, array $validExtensions): array
{
    $result = [];

    // Resolve base once (prevents per-file realpath overhead and handles normalization)
    $realBase = realpath($baseDir);
    if ($realBase === false) {
        return [];
    }
    $realBase = rtrim($realBase, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;

    // scandir() can return false on permissions
    $items = @scandir($dir);
    if ($items === false) return [];

    foreach ($items as $item) {
        // Skip dot/hidden entries
        if ($item === '.' || $item === '..' || ($item !== '' && $item[0] === '.')) {
            continue;
        }

        $fullPath = $dir . DIRECTORY_SEPARATOR . $item;

        if (is_dir($fullPath)) {
            $sub = scanDirectory($fullPath, $baseDir, $validExtensions);
            if (!empty($sub)) {
                $result[$item] = $sub;
            }
            continue;
        }

        $ext = strtolower(pathinfo($item, PATHINFO_EXTENSION));
        if (!in_array($ext, $validExtensions, true)) {
            continue;
        }

        // Normalize and enforce: file must live under baseDir
        $realFile = realpath($fullPath);
        if ($realFile === false) {
            continue;
        }
        if (strpos($realFile, $realBase) !== 0) {
            continue;
        }

        // Return relative path from baseDir
        $relativePath = substr($realFile, strlen($realBase));
        $result[$item] = $relativePath;
    }

    // Sort: folders first, then files, alphabetically
    uksort($result, function ($a, $b) use ($result) {
        $aIsDir = is_array($result[$a]);
        $bIsDir = is_array($result[$b]);

        if ($aIsDir && !$bIsDir) return -1;
        if (!$aIsDir && $bIsDir) return 1;

        // IMPORTANT: keys can be ints if the filename is numeric (e.g. "01", "2026")
        return strcasecmp((string)$a, (string)$b);
    });

    return $result;
}

$tree = scanDirectory($targetDir, $baseDir, $validExtensions);

echo json_encode(
    empty($tree) ? ['message' => 'No media files found'] : $tree,
    JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE
);