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

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

try {
    $checkout_session = \Stripe\Checkout\Session::retrieve($_GET['session_id'], ['expand' => ['subscription.discount.coupon']]);
    $subscription = $checkout_session->subscription;

    if ($subscription->status === 'active') {
        if (isset($subscription->discount) && $subscription->discount->coupon) {
            $coupon_code = $subscription->discount->coupon->name;
            if ($coupon_code) {
                $stmt = db()->prepare('UPDATE discounts SET times_used = times_used + 1 WHERE code = ?');
                $stmt->execute([$coupon_code]);
            }
        }

        $client_id = $_SESSION['user_id'];
        $stripe_subscription_id = $subscription->id;
        $stripe_product_id = $subscription->items->data[0]->price->product;
        $status = $subscription->status;
        $start_date = date('Y-m-d H:i:s', $subscription->current_period_start);
        $end_date = date('Y-m-d H:i:s', $subscription->current_period_end);

        $pdo = db();
        $stmt = $pdo->prepare("INSERT INTO client_subscriptions (client_id, stripe_subscription_id, stripe_product_id, status, start_date, end_date) VALUES (?, ?, ?, ?, ?, ?)");
        $stmt->execute([$client_id, $stripe_subscription_id, $stripe_product_id, $status, $start_date, $end_date]);

        header('Location: dashboard.php?subscription=success');
        exit;
    } else {
        header('Location: subscription-cancel.php?reason=payment_not_complete');
        exit;
    }
} catch (\Stripe\Exception\ApiErrorException $e) {
    // Handle error
    header('Location: subscription-cancel.php?reason=invalid_session');
    exit;
}