<?php
/**
 * Front-controller: single entry point for all /api/ requests.
 * Handles CORS, JSON content type, global error catching, and dispatch.
 */
require_once __DIR__ . '/../common.php';
require_once __DIR__ . '/../db_init.php';
require_once __DIR__ . '/../lib/response.php';
require_once __DIR__ . '/../lib/validate.php';

// CORS
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST, PUT, PATCH, DELETE, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type, Authorization');

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    http_response_code(204);
    exit;
}

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

// Parse route: strip /api/ prefix and .php suffix, normalize
$requestUri = $_SERVER['REQUEST_URI'] ?? '';
$path = parse_url($requestUri, PHP_URL_PATH);
$base = dirname($_SERVER['SCRIPT_NAME']);
$route = trim(substr($path, strlen($base)), '/');
$route = preg_replace('/\.php$/', '', $route);
$route = strtolower($route);

$method = $_SERVER['REQUEST_METHOD'];

// Dispatch table: route -> handler file
$routes = [
    'questionnaires'     => __DIR__ . '/../handlers/questionnaires.php',
    'questions'          => __DIR__ . '/../handlers/questions.php',
    'answer_options'     => __DIR__ . '/../handlers/answer_options.php',
    'translations'       => __DIR__ . '/../handlers/translations.php',
    'users'              => __DIR__ . '/../handlers/users.php',
    'assignments'        => __DIR__ . '/../handlers/assignments.php',
    'clients'            => __DIR__ . '/../handlers/clients.php',
    'clients/export'     => __DIR__ . '/../handlers/client_export.php',
    'clients/export_all' => __DIR__ . '/../handlers/client_export.php',
    'activity'           => __DIR__ . '/../handlers/activity.php',
    'results'            => __DIR__ . '/../handlers/results.php',
    'export'             => __DIR__ . '/../handlers/export.php',
    'app_questionnaires' => __DIR__ . '/../handlers/app_questionnaires.php',
    'logout'             => __DIR__ . '/../handlers/logout.php',
    'auth/login'         => __DIR__ . '/../handlers/auth.php',
    'auth/change-password' => __DIR__ . '/../handlers/auth.php',
    'backup'             => __DIR__ . '/../handlers/backup.php',
    'download'           => __DIR__ . '/../handlers/download.php',
];

try {
    if (!isset($routes[$route])) {
        json_error('NOT_FOUND', "Unknown endpoint: $route", 404);
    }

    $handlerFile = $routes[$route];
    if (!file_exists($handlerFile)) {
        json_error('NOT_FOUND', "Handler not found for: $route", 404);
    }

    require $handlerFile;

} catch (Throwable $e) {
    error_log("Unhandled error on $method $route: " . $e->getMessage());
    json_error('SERVER_ERROR', 'Internal server error', 500);
}