Handles frontend checkout, validation, and basic saving

functions.php

/**
 * WooCommerce Attendee System - SCRIPT 1: CORE FUNCTIONALITY
 * Handles frontend checkout, validation, and basic saving
 * Add this first to your functions.php
 */

// Check if WooCommerce is active
if (!in_array('woocommerce/woocommerce.php', apply_filters('active_plugins', get_option('active_plugins')))) {
    return;
}

// 1. ENFORCE MAXIMUM QUANTITY LIMIT OF 5 PER PRODUCT
add_filter('woocommerce_add_to_cart_validation', 'enforce_max_quantity_limit', 10, 3);
function enforce_max_quantity_limit($passed, $product_id, $quantity) {
    if (!WC() || !WC()->cart) {
        return $passed;
    }
    
    $cart_quantity = 0;
    foreach (WC()->cart->get_cart() as $cart_item) {
        if ($cart_item['product_id'] == $product_id) {
            $cart_quantity += $cart_item['quantity'];
        }
    }
    
    $total_quantity = $cart_quantity + $quantity;
    $max_quantity = 5;
    
    if ($total_quantity > $max_quantity) {
        $product = wc_get_product($product_id);
        if (!$product) {
            return false;
        }
        
        $remaining = $max_quantity - $cart_quantity;
        
        if ($remaining <= 0) {
            wc_add_notice(sprintf(
                'You already have the maximum quantity (%d) of "%s" in your cart.',
                $max_quantity,
                $product->get_name()
            ), 'error');
        } else {
            wc_add_notice(sprintf(
                'Maximum quantity allowed is %d. You can only add %d more "%s" to your cart.',
                $max_quantity,
                $remaining,
                $product->get_name()
            ), 'error');
        }
        return false;
    }
    
    return $passed;
}

// 2. ENFORCE MAX QUANTITY ON CART UPDATE
add_filter('woocommerce_update_cart_validation', 'enforce_max_quantity_on_cart_update', 10, 4);
function enforce_max_quantity_on_cart_update($passed, $cart_item_key, $values, $quantity) {
    $max_quantity = 5;
    
    if ($quantity > $max_quantity) {
        $product = wc_get_product($values['product_id']);
        if ($product) {
            wc_add_notice(sprintf(
                'Maximum quantity allowed is %d for "%s".',
                $max_quantity,
                $product->get_name()
            ), 'error');
        }
        return false;
    }
    
    return $passed;
}

// 3. ADD ATTENDEE FIELDS TO CHECKOUT
add_action('woocommerce_checkout_after_customer_details', 'add_item_specific_attendee_fields');
function add_item_specific_attendee_fields($checkout = null) {
    if (!WC() || !WC()->cart) {
        return;
    }
    
    $cart_items = WC()->cart->get_cart();
    
    if (empty($cart_items)) {
        return;
    }
    
    echo '<div id="attendee_information">';
    echo '<h3>' . esc_html__('Attendee Information', 'woocommerce') . '</h3>';
    echo '<p>' . esc_html__('Please assign each item to a specific person:', 'woocommerce') . '</p>';
    
    foreach ($cart_items as $cart_item_key => $cart_item) {
        $product = $cart_item['data'];
        if (!$product) {
            continue;
        }
        
        $product_name = $product->get_name();
        $quantity = $cart_item['quantity'];
        
        echo '<div class="product-attendee-section" style="margin: 20px 0; padding: 15px; border: 2px solid #00bcd4; border-radius: 8px; background: #f8fdff;">';
        echo '<h4 style="margin: 0 0 15px 0; color: #00bcd4; font-size: 18px;">' . esc_html($product_name) . '</h4>';
        
        for ($i = 1; $i <= $quantity; $i++) {
            echo '<div class="individual-item-group" style="border: 1px solid #ddd; padding: 15px; margin: 10px 0; background: white; border-radius: 4px;">';
            echo '<h5 style="color: #555; margin: 0 0 10px 0;">' . esc_html($product_name) . ' #' . $i . '</h5>';
            
            $field_prefix = 'item_' . sanitize_key($cart_item_key) . '_' . $i;
            
            $name_value = isset($_POST[$field_prefix . '_name']) ? sanitize_text_field($_POST[$field_prefix . '_name']) : '';
            $email_value = isset($_POST[$field_prefix . '_email']) ? sanitize_email($_POST[$field_prefix . '_email']) : '';
            $phone_value = isset($_POST[$field_prefix . '_phone']) ? sanitize_text_field($_POST[$field_prefix . '_phone']) : '';
            
            woocommerce_form_field($field_prefix . '_name', array(
                'type' => 'text',
                'class' => array('form-row-wide'),
                'label' => __('Full Name *', 'woocommerce'),
                'required' => true,
            ), $name_value);
            
            woocommerce_form_field($field_prefix . '_email', array(
                'type' => 'email',
                'class' => array('form-row-wide'),
                'label' => __('Email Address *', 'woocommerce'),
                'required' => true,
            ), $email_value);
            
            woocommerce_form_field($field_prefix . '_phone', array(
                'type' => 'tel',
                'class' => array('form-row-wide'),
                'label' => __('Phone Number *', 'woocommerce'),
                'required' => true,
            ), $phone_value);
            
            echo '</div>';
        }
        
        echo '</div>';
    }
    echo '</div>';
}

// 4. VALIDATE ATTENDEE INFORMATION
add_action('woocommerce_checkout_process', 'validate_item_specific_attendee_information');
function validate_item_specific_attendee_information() {
    if (!WC() || !WC()->cart) {
        return;
    }
    
    $cart_items = WC()->cart->get_cart();
    
    foreach ($cart_items as $cart_item_key => $cart_item) {
        $product = $cart_item['data'];
        if (!$product) {
            continue;
        }
        
        $product_name = $product->get_name();
        $quantity = $cart_item['quantity'];
        
        for ($i = 1; $i <= $quantity; $i++) {
            $field_prefix = 'item_' . sanitize_key($cart_item_key) . '_' . $i;
            
            if (empty($_POST[$field_prefix . '_name'])) {
                wc_add_notice(sprintf(__('Please enter the name for %s #%d', 'woocommerce'), $product_name, $i), 'error');
            }
            if (empty($_POST[$field_prefix . '_email'])) {
                wc_add_notice(sprintf(__('Please enter the email for %s #%d', 'woocommerce'), $product_name, $i), 'error');
            } elseif (!is_email($_POST[$field_prefix . '_email'])) {
                wc_add_notice(sprintf(__('Please enter a valid email for %s #%d', 'woocommerce'), $product_name, $i), 'error');
            }
            if (empty($_POST[$field_prefix . '_phone'])) {
                wc_add_notice(sprintf(__('Please enter the phone number for %s #%d', 'woocommerce'), $product_name, $i), 'error');
            }
        }
    }
}

// 5. SAVE ATTENDEE INFORMATION TO ORDER
add_action('woocommerce_checkout_update_order_meta', 'save_item_specific_attendee_information');
function save_item_specific_attendee_information($order_id) {
    if (!WC() || !WC()->cart) {
        return;
    }
    
    $cart_items = WC()->cart->get_cart();
    $all_attendees = array();
    
    foreach ($cart_items as $cart_item_key => $cart_item) {
        $product = $cart_item['data'];
        if (!$product) {
            continue;
        }
        
        $product_id = $cart_item['product_id'];
        $product_name = $product->get_name();
        $quantity = $cart_item['quantity'];
        
        for ($i = 1; $i <= $quantity; $i++) {
            $field_prefix = 'item_' . sanitize_key($cart_item_key) . '_' . $i;
            
            if (!empty($_POST[$field_prefix . '_name'])) {
                $all_attendees[] = array(
                    'product_id' => $product_id,
                    'product_name' => $product_name,
                    'item_number' => $i,
                    'cart_item_key' => $cart_item_key,
                    'name' => sanitize_text_field($_POST[$field_prefix . '_name']),
                    'email' => sanitize_email($_POST[$field_prefix . '_email']),
                    'phone' => sanitize_text_field($_POST[$field_prefix . '_phone'])
                );
            }
        }
    }
    
    if (!empty($all_attendees)) {
        $order = wc_get_order($order_id);
        if ($order) {
            $order->update_meta_data('_item_attendee_information', $all_attendees);
            $order->update_meta_data('_attendee_information', $all_attendees); // Backward compatibility
            $order->save();
        }
    }
}

// 6. HELPER FUNCTION TO GET ORDER ATTENDEE INFO (HPOS COMPATIBLE)
function get_order_attendee_info($order_id) {
    $order = wc_get_order($order_id);
    if (!$order) {
        return false;
    }
    
    $attendees = $order->get_meta('_item_attendee_information', true);
    
    if (!$attendees) {
        $attendees = $order->get_meta('_attendee_information', true);
    }
    
    return $attendees;
}

// 7. BASIC ADMIN DISPLAY (Simple version)
add_action('woocommerce_admin_order_data_after_billing_address', 'display_basic_attendee_info');
function display_basic_attendee_info($order) {
    if (!$order) {
        return;
    }
    
    $attendees = get_order_attendee_info($order->get_id());
    
    if ($attendees && is_array($attendees)) {
        echo '<div class="order_data_column">';
        echo '<h3>' . esc_html__('Attendee Information', 'woocommerce') . '</h3>';
        
        foreach ($attendees as $attendee) {
            $product_name = isset($attendee['product_name']) ? $attendee['product_name'] : __('Unknown Product', 'woocommerce');
            $item_number = isset($attendee['item_number']) ? $attendee['item_number'] : '?';
            
            echo '<div style="margin-bottom: 10px; padding: 10px; border: 1px solid #ddd; background: #f9f9f9;">';
            echo '<strong>' . esc_html($product_name) . ' #' . esc_html($item_number) . ':</strong><br>';
            echo __('Name:', 'woocommerce') . ' ' . esc_html($attendee['name'] ?? 'N/A') . '<br>';
            echo __('Email:', 'woocommerce') . ' ' . esc_html($attendee['email'] ?? 'N/A') . '<br>';
            echo __('Phone:', 'woocommerce') . ' ' . esc_html($attendee['phone'] ?? 'N/A') . '<br>';
            echo '</div>';
        }
        echo '</div>';
    }
}

// 8. CSS FOR CHECKOUT STYLING
add_action('wp_head', 'item_attendee_form_styles');
function item_attendee_form_styles() {
    if (is_checkout()) {
        ?>
        <style>
            #woocommerce-additional-fields {
                display: none !important;
            }
            #attendee_information {
                display: block;
                margin: 20px 0;
                padding: 20px;
                border: 2px solid #00bcd4;
                border-radius: 8px;
                background-color: #f8fdff;
            }
            #attendee_information h3 {
                margin: 0 0 15px;
                color: #00bcd4;
                font-size: 24px;
            }
            .product-attendee-section {
                animation: fadeIn 0.3s ease-in;
            }
            .individual-item-group {
                background-color: white;
                border-radius: 4px;
                transition: box-shadow 0.2s ease;
            }
            .individual-item-group:hover {
                box-shadow: 0 2px 8px rgba(0,188,212,0.1);
            }
            .individual-item-group h5 {
                font-weight: 600;
                border-bottom: 1px solid #eee;
                padding-bottom: 8px;
            }
            .individual-item-group p {
                margin: 10px 0 0 0 !important; 
            }
            @keyframes fadeIn {
                from { opacity: 0; transform: translateY(10px); }
                to { opacity: 1; transform: translateY(0); }
            }
        </style>
        <?php
    }
}

// 9. REQUEST INVOICE PAYMENT METHOD
add_filter('woocommerce_payment_gateways', 'add_request_invoice_gateway');
function add_request_invoice_gateway($gateways) {
    $gateways[] = 'WC_Gateway_Request_Invoice';
    return $gateways;
}

add_action('plugins_loaded', 'init_request_invoice_gateway_class');
function init_request_invoice_gateway_class() {
    if (!class_exists('WC_Payment_Gateway')) {
        return;
    }
    
    class WC_Gateway_Request_Invoice extends WC_Payment_Gateway {
        
        public function __construct() {
            $this->id                 = 'request_invoice';
            $this->icon               = '';
            $this->has_fields         = false;
            $this->method_title       = __('Request Invoice', 'woocommerce');
            $this->method_description = __('Allow customers to request an invoice for manual payment.', 'woocommerce');
            
            $this->init_form_fields();
            $this->init_settings();
            
            $this->title        = $this->get_option('title');
            $this->description  = $this->get_option('description');
            $this->enabled      = $this->get_option('enabled');
            
            add_action('woocommerce_update_options_payment_gateways_' . $this->id, array($this, 'process_admin_options'));
        }
        
        public function init_form_fields() {
            $this->form_fields = array(
                'enabled' => array(
                    'title'   => __('Enable/Disable', 'woocommerce'),
                    'type'    => 'checkbox',
                    'label'   => __('Enable Request Invoice', 'woocommerce'),
                    'default' => 'yes'
                ),
                'title' => array(
                    'title'       => __('Title', 'woocommerce'),
                    'type'        => 'text',
                    'description' => __('This controls the title which the user sees during checkout.', 'woocommerce'),
                    'default'     => __('Request Invoice', 'woocommerce'),
                    'desc_tip'    => true,
                ),
                'description' => array(
                    'title'       => __('Description', 'woocommerce'),
                    'type'        => 'textarea',
                    'description' => __('Payment method description that the customer will see on your checkout.', 'woocommerce'),
                    'default'     => __('Select this option to receive a formal invoice for your records or internal processing. No payment is required now — we'll send you an official invoice with payment details shortly after you place your order.', 'woocommerce'),
                ),
            );
        }
        
        public function process_payment($order_id) {
            $order = wc_get_order($order_id);
            if (!$order) {
                return array(
                    'result'   => 'fail',
                    'messages' => __('Order not found.', 'woocommerce')
                );
            }
            
            $order->update_status('pending', __('Awaiting invoice payment', 'woocommerce'));
            $order->add_order_note(__('Customer requested invoice. Manual payment required.', 'woocommerce'));
            
            $this->send_invoice_notifications($order);
            
            wc_reduce_stock_levels($order_id);
            
            if (WC()->cart) {
                WC()->cart->empty_cart();
            }
            
            return array(
                'result'   => 'success',
                'redirect' => $this->get_return_url($order)
            );
        }
        
        private function send_invoice_notifications($order) {
            $admin_email = get_option('admin_email');
            $invoice_email = '[email protected]';
            
            $subject = sprintf(__('Invoice Request - Order #%s', 'woocommerce'), $order->get_order_number());
            
            $message = __("New invoice request received!\n\n", 'woocommerce');
            $message .= __("Order #: ", 'woocommerce') . $order->get_order_number() . "\n";
            $message .= __("Date: ", 'woocommerce') . $order->get_date_created()->format('Y-m-d H:i:s') . "\n";
            $message .= __("Customer: ", 'woocommerce') . $order->get_billing_first_name() . " " . $order->get_billing_last_name() . "\n";
            $message .= __("Email: ", 'woocommerce') . $order->get_billing_email() . "\n";
            $message .= __("Total: ", 'woocommerce') . $order->get_formatted_order_total() . "\n\n";
            
            $message .= __("Items:\n", 'woocommerce');
            foreach ($order->get_items() as $item) {
                $message .= "- " . $item->get_name() . " (" . __("Qty: ", 'woocommerce') . $item->get_quantity() . ")\n";
            }
            
            $attendees = get_order_attendee_info($order->get_id());
            if ($attendees && is_array($attendees)) {
                $message .= "\n" . __("Item Assignments:\n", 'woocommerce');
                foreach ($attendees as $attendee) {
                    $prod_name = isset($attendee['product_name']) ? $attendee['product_name'] : __('Unknown', 'woocommerce');
                    $item_num = isset($attendee['item_number']) ? $attendee['item_number'] : '?';
                    $message .= "- " . $prod_name . " #" . $item_num . ": " . $attendee['name'] . " (" . $attendee['email'] . ") - " . $attendee['phone'] . "\n";
                }
            }
            
            $message .= "\n" . __("View order: ", 'woocommerce') . admin_url('post.php?post=' . $order->get_id() . '&action=edit');
            
            wp_mail($admin_email, $subject, $message);
            if ($invoice_email !== $admin_email) {
                wp_mail($invoice_email, $subject, $message);
            }
        }
    }
}

// 10. DISABLE ORDER NOTES FIELD
add_filter('woocommerce_enable_order_notes_field', '__return_false');