checkout.php

<?php
include('header.php');

$userId = $_SESSION['id']; // Get the user ID from the session

// Fetch existing addresses for the user
$addressQuery = "SELECT * FROM user_addresses WHERE u_id = $userId";
$addresses = mysqli_query($conn, $addressQuery);

// Handle form submission
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $address = $_POST['address']; // Address the user selects or enters
    $payment_method = $_POST['payment_method']; // Payment method selected by the user

    // Insert a new address if the user has selected "Add New Address"
    if (isset($_POST['new_address'])) {
        $insertAddressQuery = "INSERT INTO user_addresses (u_id, address) VALUES ($userId, '$address')";
        mysqli_query($conn, $insertAddressQuery);
    }

    // Insert order into the orders table
    $orderQuery = "INSERT INTO orders (u_id, order_date, status) VALUES ($userId, NOW(), 'Pending')";
    if (mysqli_query($conn, $orderQuery)) {
        $orderId = mysqli_insert_id($conn); // Get the generated order ID

        // Fetch cart items for the user
        $cartQuery = "SELECT c.p_id, c.quantity, p.price FROM cart c JOIN product p ON c.p_id = p.p_id WHERE c.u_id = $userId";
        $cartItems = mysqli_query($conn, $cartQuery);

        // Insert each cart item into order_details table
        while ($item = mysqli_fetch_assoc($cartItems)) {
            $p_id = $item['p_id'];
            $quantity = $item['quantity'];
            $price = $item['price'];

            $orderDetailQuery = "INSERT INTO order_details (order_id, p_id, quantity, price) 
                                 VALUES ($orderId, $p_id, $quantity, $price)";
            mysqli_query($conn, $orderDetailQuery);
        }

        // Clear the cart after placing the order
        $clearCartQuery = "DELETE FROM cart WHERE u_id = $userId";
        mysqli_query($conn, $clearCartQuery);

        // Insert into admin_order_request to notify admin
        $adminOrderRequestQuery = "INSERT INTO admin_order_request (order_id, u_id, status) 
                                   VALUES ($orderId, $userId, 'Pending')";
        mysqli_query($conn, $adminOrderRequestQuery);

        // Show success message
        echo "Order placed successfully!";
    } else {
        echo "Error placing order: " . mysqli_error($conn);
    }
}
?>

<form method="POST">
    <h3>Choose Your Address</h3>
    <?php if (mysqli_num_rows($addresses) > 0): ?>
        <p>Select an Address</p>
        <?php while ($address = mysqli_fetch_assoc($addresses)): ?>
            <label>
                <input type="radio" name="address" value="<?= $address['address']; ?>" required>
                <?= $address['address']; ?>
            </label><br>
        <?php endwhile; ?>
        <button type="submit" name="new_address" value="1">Add New Address</button>
    <?php else: ?>
        <textarea name="address" placeholder="Enter your address" required></textarea><br>
    <?php endif; ?>

    <h3>Select Payment Method</h3>
    <label><input type="radio" name="payment_method" value="COD" checked> Cash on Delivery</label><br>
    <label><input type="radio" name="payment_method" value="UPI"> UPI/Net Banking (Demo)</label><br>

    <button type="submit" name="place_order">Place Order</button>
</form>