Initial implementation of WooCommerce Composable Products plugin

Implemented custom WooCommerce product type allowing customers to build their own
product bundles by selecting from predefined sets of products.

Features:
- Custom "Composable Product" type with admin interface
- Product selection by category, tag, or SKU
- Configurable selection limits (global and per-product)
- Dual pricing modes: fixed price or sum of selected products
- Modern responsive frontend with Twig templates
- AJAX add-to-cart functionality
- Full internationalization support (.pot file)
- WooCommerce settings integration
- Comprehensive documentation

Technical implementation:
- PHP 8.3+ with PSR-4 autoloading
- Twig 3.0 templating engine via Composer
- Vanilla JavaScript with jQuery for frontend interactions
- WordPress and WooCommerce hooks for seamless integration
- Security: input sanitization, validation, and output escaping
- Translation-ready with text domain 'wc-composable-product'

Documentation:
- README.md: Project overview and features
- INSTALL.md: Installation and usage guide
- IMPLEMENTATION.md: Technical architecture
- CHANGELOG.md: Version history

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

includes/Admin/Product_Data.php

@@ -0,0 +1,190 @@
+<?php
+/**
+ * Product Data Tab
+ *
+ * @package WC_Composable_Product
+ */
+
+namespace WC_Composable_Product\Admin;
+
+defined('ABSPATH') || exit;
+
+/**
+ * Product Data Tab Class
+ */
+class Product_Data {
+    /**
+     * Constructor
+     */
+    public function __construct() {
+        add_filter('woocommerce_product_data_tabs', [$this, 'add_product_data_tab']);
+        add_action('woocommerce_product_data_panels', [$this, 'add_product_data_panel']);
+        add_action('woocommerce_process_product_meta_composable', [$this, 'save_product_data']);
+        add_action('woocommerce_product_options_general_product_data', [$this, 'add_general_fields']);
+    }
+
+    /**
+     * Add composable products tab
+     *
+     * @param array $tabs Product data tabs
+     * @return array
+     */
+    public function add_product_data_tab($tabs) {
+        $tabs['composable'] = [
+            'label' => __('Composable Options', 'wc-composable-product'),
+            'target' => 'composable_product_data',
+            'class' => ['show_if_composable'],
+            'priority' => 21,
+        ];
+        return $tabs;
+    }
+
+    /**
+     * Add fields to general tab
+     */
+    public function add_general_fields() {
+        global $product_object;
+
+        if ($product_object && $product_object->get_type() === 'composable') {
+            echo '<div class="options_group show_if_composable">';
+
+            woocommerce_wp_text_input([
+                'id' => '_composable_selection_limit',
+                'label' => __('Selection Limit', 'wc-composable-product'),
+                'description' => __('Maximum number of items customers can select. Leave empty to use global default.', 'wc-composable-product'),
+                'desc_tip' => true,
+                'type' => 'number',
+                'custom_attributes' => [
+                    'min' => '1',
+                    'step' => '1',
+                ],
+            ]);
+
+            woocommerce_wp_select([
+                'id' => '_composable_pricing_mode',
+                'label' => __('Pricing Mode', 'wc-composable-product'),
+                'description' => __('How to calculate the price. Leave empty to use global default.', 'wc-composable-product'),
+                'desc_tip' => true,
+                'options' => [
+                    '' => __('Use global default', 'wc-composable-product'),
+                    'sum' => __('Sum of selected products', 'wc-composable-product'),
+                    'fixed' => __('Fixed price', 'wc-composable-product'),
+                ],
+            ]);
+
+            echo '</div>';
+        }
+    }
+
+    /**
+     * Add product data panel
+     */
+    public function add_product_data_panel() {
+        global $post;
+        ?>
+        <div id="composable_product_data" class="panel woocommerce_options_panel hidden">
+            <div class="options_group">
+                <?php
+                woocommerce_wp_select([
+                    'id' => '_composable_criteria_type',
+                    'label' => __('Selection Criteria', 'wc-composable-product'),
+                    'description' => __('How to select available products.', 'wc-composable-product'),
+                    'desc_tip' => true,
+                    'options' => [
+                        'category' => __('By Category', 'wc-composable-product'),
+                        'tag' => __('By Tag', 'wc-composable-product'),
+                        'sku' => __('By SKU', 'wc-composable-product'),
+                    ],
+                    'value' => get_post_meta($post->ID, '_composable_criteria_type', true) ?: 'category',
+                ]);
+                ?>
+            </div>
+
+            <div class="options_group composable_criteria_group" id="composable_criteria_category">
+                <p class="form-field">
+                    <label for="_composable_categories"><?php esc_html_e('Select Categories', 'wc-composable-product'); ?></label>
+                    <select id="_composable_categories" name="_composable_categories[]" class="wc-enhanced-select" multiple="multiple" style="width: 50%;">
+                        <?php
+                        $selected_categories = get_post_meta($post->ID, '_composable_categories', true) ?: [];
+                        $categories = get_terms(['taxonomy' => 'product_cat', 'hide_empty' => false]);
+                        foreach ($categories as $category) {
+                            printf(
+                                '<option value="%s" %s>%s</option>',
+                                esc_attr($category->term_id),
+                                selected(in_array($category->term_id, (array) $selected_categories), true, false),
+                                esc_html($category->name)
+                            );
+                        }
+                        ?>
+                    </select>
+                    <span class="description"><?php esc_html_e('Select product categories to include.', 'wc-composable-product'); ?></span>
+                </p>
+            </div>
+
+            <div class="options_group composable_criteria_group" id="composable_criteria_tag" style="display: none;">
+                <p class="form-field">
+                    <label for="_composable_tags"><?php esc_html_e('Select Tags', 'wc-composable-product'); ?></label>
+                    <select id="_composable_tags" name="_composable_tags[]" class="wc-enhanced-select" multiple="multiple" style="width: 50%;">
+                        <?php
+                        $selected_tags = get_post_meta($post->ID, '_composable_tags', true) ?: [];
+                        $tags = get_terms(['taxonomy' => 'product_tag', 'hide_empty' => false]);
+                        foreach ($tags as $tag) {
+                            printf(
+                                '<option value="%s" %s>%s</option>',
+                                esc_attr($tag->term_id),
+                                selected(in_array($tag->term_id, (array) $selected_tags), true, false),
+                                esc_html($tag->name)
+                            );
+                        }
+                        ?>
+                    </select>
+                    <span class="description"><?php esc_html_e('Select product tags to include.', 'wc-composable-product'); ?></span>
+                </p>
+            </div>
+
+            <div class="options_group composable_criteria_group" id="composable_criteria_sku" style="display: none;">
+                <?php
+                woocommerce_wp_textarea_input([
+                    'id' => '_composable_skus',
+                    'label' => __('Product SKUs', 'wc-composable-product'),
+                    'description' => __('Enter product SKUs separated by commas.', 'wc-composable-product'),
+                    'desc_tip' => true,
+                    'placeholder' => __('SKU-1, SKU-2, SKU-3', 'wc-composable-product'),
+                ]);
+                ?>
+            </div>
+        </div>
+        <?php
+    }
+
+    /**
+     * Save product data
+     *
+     * @param int $post_id Post ID
+     */
+    public function save_product_data($post_id) {
+        // Save selection limit
+        $selection_limit = isset($_POST['_composable_selection_limit']) ? absint($_POST['_composable_selection_limit']) : '';
+        update_post_meta($post_id, '_composable_selection_limit', $selection_limit);
+
+        // Save pricing mode
+        $pricing_mode = isset($_POST['_composable_pricing_mode']) ? sanitize_text_field($_POST['_composable_pricing_mode']) : '';
+        update_post_meta($post_id, '_composable_pricing_mode', $pricing_mode);
+
+        // Save criteria type
+        $criteria_type = isset($_POST['_composable_criteria_type']) ? sanitize_text_field($_POST['_composable_criteria_type']) : 'category';
+        update_post_meta($post_id, '_composable_criteria_type', $criteria_type);
+
+        // Save categories
+        $categories = isset($_POST['_composable_categories']) ? array_map('absint', $_POST['_composable_categories']) : [];
+        update_post_meta($post_id, '_composable_categories', $categories);
+
+        // Save tags
+        $tags = isset($_POST['_composable_tags']) ? array_map('absint', $_POST['_composable_tags']) : [];
+        update_post_meta($post_id, '_composable_tags', $tags);
+
+        // Save SKUs
+        $skus = isset($_POST['_composable_skus']) ? sanitize_textarea_field($_POST['_composable_skus']) : '';
+        update_post_meta($post_id, '_composable_skus', $skus);
+    }
+}

includes/Admin/Settings.php

@@ -0,0 +1,108 @@
+<?php
+/**
+ * Admin Settings
+ *
+ * @package WC_Composable_Product
+ */
+
+namespace WC_Composable_Product\Admin;
+
+defined('ABSPATH') || exit;
+
+/**
+ * Settings class
+ */
+class Settings extends \WC_Settings_Page {
+    /**
+     * Constructor
+     */
+    public function __construct() {
+        $this->id = 'composable_products';
+        $this->label = __('Composable Products', 'wc-composable-product');
+
+        parent::__construct();
+    }
+
+    /**
+     * Get settings array
+     *
+     * @return array
+     */
+    public function get_settings() {
+        $settings = [
+            [
+                'title' => __('Composable Products Settings', 'wc-composable-product'),
+                'type' => 'title',
+                'desc' => __('Configure default settings for composable products.', 'wc-composable-product'),
+                'id' => 'wc_composable_settings',
+            ],
+            [
+                'title' => __('Default Selection Limit', 'wc-composable-product'),
+                'desc' => __('Default number of items customers can select.', 'wc-composable-product'),
+                'id' => 'wc_composable_default_limit',
+                'type' => 'number',
+                'default' => '5',
+                'custom_attributes' => [
+                    'min' => '1',
+                    'step' => '1',
+                ],
+                'desc_tip' => true,
+            ],
+            [
+                'title' => __('Default Pricing Mode', 'wc-composable-product'),
+                'desc' => __('How to calculate the price of composable products.', 'wc-composable-product'),
+                'id' => 'wc_composable_default_pricing',
+                'type' => 'select',
+                'default' => 'sum',
+                'options' => [
+                    'sum' => __('Sum of selected products', 'wc-composable-product'),
+                    'fixed' => __('Fixed price', 'wc-composable-product'),
+                ],
+                'desc_tip' => true,
+            ],
+            [
+                'title' => __('Show Product Images', 'wc-composable-product'),
+                'desc' => __('Display product images in the selection interface.', 'wc-composable-product'),
+                'id' => 'wc_composable_show_images',
+                'type' => 'checkbox',
+                'default' => 'yes',
+            ],
+            [
+                'title' => __('Show Product Prices', 'wc-composable-product'),
+                'desc' => __('Display individual product prices in the selection interface.', 'wc-composable-product'),
+                'id' => 'wc_composable_show_prices',
+                'type' => 'checkbox',
+                'default' => 'yes',
+            ],
+            [
+                'title' => __('Show Total Price', 'wc-composable-product'),
+                'desc' => __('Display the total price as customers make selections.', 'wc-composable-product'),
+                'id' => 'wc_composable_show_total',
+                'type' => 'checkbox',
+                'default' => 'yes',
+            ],
+            [
+                'type' => 'sectionend',
+                'id' => 'wc_composable_settings',
+            ],
+        ];
+
+        return apply_filters('wc_composable_settings', $settings);
+    }
+
+    /**
+     * Output the settings
+     */
+    public function output() {
+        $settings = $this->get_settings();
+        \WC_Admin_Settings::output_fields($settings);
+    }
+
+    /**
+     * Save settings
+     */
+    public function save() {
+        $settings = $this->get_settings();
+        \WC_Admin_Settings::save_fields($settings);
+    }
+}