<?php
/**
 * Recurring Tickets Management API
 * CRUD operations for recurring_tickets table
 */

ini_set('display_errors', 0);
error_reporting(E_ALL);

require_once dirname(__DIR__) . '/middleware/RateLimitMiddleware.php';
RateLimitMiddleware::apply('api');

try {
    require_once dirname(__DIR__) . '/config/config.php';
    require_once dirname(__DIR__) . '/helpers/Database.php';
    require_once dirname(__DIR__) . '/models/RecurringTicketModel.php';

    // Check authentication
    if (session_status() === PHP_SESSION_NONE) session_start();
    if (!isset($_SESSION['user']) || !isset($_SESSION['user']['user_id'])) {
        http_response_code(401);
        echo json_encode(['success' => false, 'error' => 'Authentication required']);
        exit;
    }

    // Check admin privileges
    if (!$_SESSION['user']['is_admin']) {
        http_response_code(403);
        echo json_encode(['success' => false, 'error' => 'Admin privileges required']);
        exit;
    }

    $currentUserId = $_SESSION['user']['user_id'];

    // CSRF Protection for write operations
    if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
        require_once dirname(__DIR__) . '/middleware/CsrfMiddleware.php';
        $csrfToken = $_SERVER['HTTP_X_CSRF_TOKEN'] ?? '';
        if (!CsrfMiddleware::validateToken($csrfToken)) {
            http_response_code(403);
            echo json_encode(['success' => false, 'error' => 'Invalid CSRF token']);
            exit;
        }
    }

    // Use centralized database connection
    $conn = Database::getConnection();

    header('Content-Type: application/json');

    $model = new RecurringTicketModel($conn);
    $method = $_SERVER['REQUEST_METHOD'];
    $id = isset($_GET['id']) ? (int)$_GET['id'] : null;
    $action = isset($_GET['action']) ? $_GET['action'] : null;

    switch ($method) {
        case 'GET':
            if ($id) {
                $recurring = $model->getById($id);
                echo json_encode(['success' => (bool)$recurring, 'recurring' => $recurring]);
            } else {
                $all = $model->getAll(true);
                echo json_encode(['success' => true, 'recurring_tickets' => $all]);
            }
            break;

        case 'POST':
            if ($action === 'toggle' && $id) {
                $result = $model->toggleActive($id);
                echo json_encode($result);
            } else {
                $data = json_decode(file_get_contents('php://input'), true);
                if (!is_array($data) || empty($data['schedule_type']) || empty($data['title_template'])) {
                    echo json_encode(['success' => false, 'error' => 'schedule_type and title_template are required']);
                    exit;
                }

                // Calculate next run time
                $nextRun = calculateNextRun(
                    $data['schedule_type'],
                    $data['schedule_day'] ?? null,
                    $data['schedule_time'] ?? '09:00'
                );

                $data['next_run_at'] = $nextRun;
                $data['is_active'] = isset($data['is_active']) ? (int)$data['is_active'] : 1;
                $data['created_by'] = $currentUserId;

                $result = $model->create($data);
                echo json_encode($result);
            }
            break;

        case 'PUT':
            if (!$id) {
                echo json_encode(['success' => false, 'error' => 'ID required']);
                exit;
            }

            $data = json_decode(file_get_contents('php://input'), true);
            if (!is_array($data) || empty($data['schedule_type'])) {
                echo json_encode(['success' => false, 'error' => 'Invalid request data']);
                exit;
            }

            // Recalculate next run time if schedule changed
            $nextRun = calculateNextRun(
                $data['schedule_type'],
                $data['schedule_day'] ?? null,
                $data['schedule_time'] ?? '09:00'
            );
            $data['next_run_at'] = $nextRun;
            $data['is_active'] = isset($data['is_active']) ? (int)$data['is_active'] : 1;

            $result = $model->update($id, $data);
            echo json_encode($result);
            break;

        case 'DELETE':
            if (!$id) {
                echo json_encode(['success' => false, 'error' => 'ID required']);
                exit;
            }

            $result = $model->delete($id);
            echo json_encode($result);
            break;

        default:
            http_response_code(405);
            echo json_encode(['success' => false, 'error' => 'Method not allowed']);
    }

} catch (Exception $e) {
    error_log("Recurring tickets API error: " . $e->getMessage());
    http_response_code(500);
    echo json_encode(['success' => false, 'error' => 'An internal error occurred']);
}

function calculateNextRun($scheduleType, $scheduleDay, $scheduleTime) {
    $now = new DateTime();
    $time = $scheduleTime ?: '09:00';

    switch ($scheduleType) {
        case 'daily':
            $next = new DateTime('tomorrow ' . $time);
            break;

        case 'weekly':
            $days = [1 => 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'];
            $dayName = $days[(int)$scheduleDay] ?? 'Monday';
            $next = new DateTime("next {$dayName} " . $time);
            break;

        case 'monthly':
            $day = max(1, min(31, (int)$scheduleDay));
            $next = new DateTime();
            $next->modify('first day of next month');
            // Clamp to last day of target month (handles Feb, 30-day months)
            $daysInMonth = (int)$next->format('t');
            $day = min($day, $daysInMonth);
            $next->setDate((int)$next->format('Y'), (int)$next->format('m'), $day);
            $parts = explode(':', $time . ':00'); // ensure at least H:M
            $next->setTime((int)$parts[0], (int)$parts[1], 0);
            break;

        default:
            $next = new DateTime('tomorrow ' . $time);
    }

    return $next->format('Y-m-d H:i:s');
}