<?php
session_start();

if (!isset($_SESSION['user_id'])) {
    header("Location: login.php");
    exit();
}

require_once 'db/config.php';

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $event_id = $_POST['event_id'] ?? null;
    $title = $_POST['title'] ?? '';
    $description = $_POST['description'] ?? '';
    $start_datetime = $_POST['start_datetime'] ?? '';
    $end_datetime = $_POST['end_datetime'] ?? '';
    $event_type_id = $_POST['event_type_id'] ?? null;

    // For now, we don't support updating recurring events.
    // This will be implemented in the future.

    if (empty($event_id) || empty($title) || empty($start_datetime) || empty($end_datetime) || empty($event_type_id)) {
        header("Location: calendar.php?error=empty_fields");
        exit();
    }

    $pdo = db();
    $stmt = $pdo->prepare("UPDATE calendar_events SET title = ?, description = ?, start_datetime = ?, end_datetime = ?, event_type_id = ? WHERE id = ?");
    
    try {
        $stmt->execute([$title, $description, $start_datetime, $end_datetime, $event_type_id, $event_id]);
        header("Location: calendar.php");
        exit();
    } catch (PDOException $e) {
        // Handle database error
        error_log($e->getMessage());
        header("Location: calendar.php?error=db_error");
        exit();
    }
}