<?php
require_once 'config.php';
header('Content-Type: application/json');

// Ensure user is authenticated
if (!isset($_SESSION['authenticated']) || $_SESSION['authenticated'] !== true) {
    echo json_encode(["error" => "Unauthorized"]);
    http_response_code(401);
    exit;
}

// Ensure the request is a POST
if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    echo json_encode(['success' => false, 'error' => 'Invalid request method.']);
    exit;
}

$headers = array_change_key_case(getallheaders(), CASE_LOWER);
$receivedToken = isset($headers['x-csrf-token']) ? trim($headers['x-csrf-token']) : '';

if ($receivedToken !== $_SESSION['csrf_token']) {
    echo json_encode(['success' => false, 'error' => 'Invalid CSRF token.']);
    http_response_code(403);
    exit;
}

$username = $_SESSION['username'] ?? '';
$userPermissions = loadUserPermissions($username);
if ($username) {
    $userPermissions = loadUserPermissions($username);
    if (isset($userPermissions['readOnly']) && $userPermissions['readOnly'] === true) {
        echo json_encode(["error" => "Read-only users are not allowed to delete folders."]);
        exit();
    }
}

// Get the JSON input and decode it
$input = json_decode(file_get_contents('php://input'), true);
if (!isset($input['folder'])) {
    echo json_encode(['success' => false, 'error' => 'Folder name not provided.']);
    exit;
}

$folderName = trim($input['folder']);

// Prevent deletion of root.
if ($folderName === 'root') {
    echo json_encode(['success' => false, 'error' => 'Cannot delete root folder.']);
    exit;
}

// Allow letters, numbers, underscores, dashes, spaces, and forward slashes.
if (!preg_match(REGEX_FOLDER_NAME, $folderName)) {
    echo json_encode(['success' => false, 'error' => 'Invalid folder name.']);
    exit;
}

// Build the folder path (supports subfolder paths like "FolderTest/FolderTestSub")
$folderPath = rtrim(UPLOAD_DIR, '/\\') . DIRECTORY_SEPARATOR . $folderName;

// Check if the folder exists and is a directory
if (!file_exists($folderPath) || !is_dir($folderPath)) {
    echo json_encode(['success' => false, 'error' => 'Folder does not exist.']);
    exit;
}

// Prevent deletion if the folder is not empty
if (count(scandir($folderPath)) > 2) {
    echo json_encode(['success' => false, 'error' => 'Folder is not empty.']);
    exit;
}

/**
 * Helper: Generate the metadata file path for a given folder.
 * For "root", returns "root_metadata.json". Otherwise, it replaces
 * slashes, backslashes, and spaces with dashes and appends "_metadata.json".
 *
 * @param string $folder The folder's relative path.
 * @return string The full path to the folder's metadata file.
 */
function getMetadataFilePath($folder) {
    if (strtolower($folder) === 'root' || $folder === '') {
        return META_DIR . "root_metadata.json";
    }
    return META_DIR . str_replace(['/', '\\', ' '], '-', $folder) . '_metadata.json';
}

// Attempt to delete the folder.
if (rmdir($folderPath)) {
    // Remove corresponding metadata file if it exists.
    $metadataFile = getMetadataFilePath($folderName);
    if (file_exists($metadataFile)) {
        unlink($metadataFile);
    }
    echo json_encode(['success' => true]);
} else {
    echo json_encode(['success' => false, 'error' => 'Failed to delete folder.']);
}
?>