<?php
session_start();
require_once 'db/config.php';
require_once 'stripe/init.php';

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

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $coach_id = $_POST['coach_id'];
    $client_id = $_SESSION['user_id'];
    $booking_time = $_POST['booking_time'];

    $pdo = db();

    // Check if the client has an active package with this coach
    $pkg_stmt = $pdo->prepare(
        "SELECT cp.id, cp.sessions_remaining, sp.type, sp.client_limit FROM client_packages cp JOIN service_packages sp ON cp.package_id = sp.id WHERE cp.client_id = ? AND sp.coach_id = ? AND cp.sessions_remaining > 0 ORDER BY cp.purchase_date ASC LIMIT 1"
    );
    $pkg_stmt->execute([$client_id, $coach_id]);
    $active_package = $pkg_stmt->fetch();

    if ($active_package) {
        // Use a session from the package
        try {
            $pdo->beginTransaction();

            $is_recurring = isset($_POST['recurring']) && $_POST['recurring'] === 'on';
            $recurrences = $is_recurring ? (int)$_POST['recurrences'] : 1;
            $frequency = $is_recurring ? $_POST['frequency'] : 'weekly'; // Default to weekly

            if ($active_package['sessions_remaining'] < $recurrences) {
                throw new Exception('Not enough sessions remaining in the package.');
            }

            $current_booking_time = new DateTime($booking_time);

            for ($i = 0; $i < $recurrences; $i++) {
                if ($active_package['type'] === 'group') {
                    $count_stmt = $pdo->prepare("SELECT COUNT(*) FROM bookings WHERE coach_id = ? AND booking_time = ? AND status IN ('pending', 'confirmed')");
                    $count_stmt->execute([$coach_id, $current_booking_time->format('Y-m-d H:i:s')]);
                    $current_bookings = $count_stmt->fetchColumn();

                    if ($current_bookings >= $active_package['client_limit']) {
                        throw new Exception('This group session is already full.');
                    }
                }

                // 1. Create the booking
                $book_stmt = $pdo->prepare(
                    "INSERT INTO bookings (coach_id, client_id, booking_time, status, payment_status) VALUES (?, ?, ?, 'pending', 'paid_with_package')"
                );
                $book_stmt->execute([$coach_id, $client_id, $current_booking_time->format('Y-m-d H:i:s')]);

                // 2. Decrement remaining sessions
                $update_pkg_stmt = $pdo->prepare("UPDATE client_packages SET sessions_remaining = sessions_remaining - 1 WHERE id = ?");
                $update_pkg_stmt->execute([$active_package['id']]);

                // Calculate next booking time
                if ($i < $recurrences - 1) {
                    if ($frequency === 'weekly') {
                        $current_booking_time->modify('+1 week');
                    } elseif ($frequency === 'bi-weekly') {
                        $current_booking_time->modify('+2 weeks');
                    }
                }
            }

            $pdo->commit();

            // Send email notification to coach
            require_once __DIR__ . '/mail/MailService.php';
            $coach_stmt = $pdo->prepare("SELECT email FROM coaches WHERE id = ?");
            $coach_stmt->execute([$coach_id]);
            $coach = $coach_stmt->fetch();

            $client_stmt = $pdo->prepare("SELECT name FROM clients WHERE id = ?");
            $client_stmt->execute([$client_id]);
            $client = $client_stmt->fetch();

            if ($coach && $client) {
                $to = $coach['email'];
                $subject = 'New Pending Booking';
                $message = "You have a new booking from {$client['name']} for {$booking_time}. Please log in to your dashboard to approve or decline it.";
                MailService::sendMail($to, $subject, $message, $message);
            }

            header('Location: dashboard.php?booking=pending');
            exit;

        } catch (Exception $e) {
            $pdo->rollBack();
            error_log('Package booking failed: ' . $e->getMessage());
            header('Location: profile.php?id=' . $coach_id . '&error=booking_failed');
            exit;
        }

    } else {
        // No active package, redirect to coach's profile to purchase one
        header('Location: profile.php?id=' . $coach_id . '&error=no_package');
        exit;
    }
} else {
    header('Location: coaches.php');
    exit;
}