<?php
/**
 * Main Plugin Class
 *
 * @package WC_Composable_Product
 */

namespace WC_Composable_Product;

defined('ABSPATH') || exit;

/**
 * Main plugin class - Singleton pattern
 */
class Plugin {
    /**
     * The single instance of the class
     *
     * @var Plugin
     */
    protected static $instance = null;

    /**
     * Twig environment
     *
     * @var \Twig\Environment
     */
    private $twig = null;

    /**
     * Main Plugin Instance
     *
     * Ensures only one instance is loaded or can be loaded.
     *
     * @return Plugin
     */
    public static function instance() {
        if (is_null(self::$instance)) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    /**
     * Constructor
     */
    private function __construct() {
        $this->init_hooks();
        $this->init_twig();
        $this->includes();
    }

    /**
     * Hook into WordPress and WooCommerce
     */
    private function init_hooks() {
        // Register product type
        add_filter('product_type_selector', [$this, 'add_product_type']);
        add_filter('woocommerce_product_class', [$this, 'product_class'], 10, 2);

        // Enqueue scripts and styles
        add_action('wp_enqueue_scripts', [$this, 'enqueue_frontend_scripts']);
        add_action('admin_enqueue_scripts', [$this, 'enqueue_admin_scripts']);

        // Admin settings
        add_filter('woocommerce_get_settings_pages', [$this, 'add_settings_page']);
    }

    /**
     * Initialize Twig template engine
     */
    private function init_twig() {
        $loader = new \Twig\Loader\FilesystemLoader(WC_COMPOSABLE_PRODUCT_PATH . 'templates');
        $this->twig = new \Twig\Environment($loader, [
            'cache' => WC_COMPOSABLE_PRODUCT_PATH . 'cache',
            'auto_reload' => true,
            'debug' => defined('WP_DEBUG') && WP_DEBUG,
        ]);

        // Add WordPress functions to Twig
        $this->twig->addFunction(new \Twig\TwigFunction('__', function($text) {
            return __($text, 'wc-composable-product');
        }));
        $this->twig->addFunction(new \Twig\TwigFunction('esc_html', 'esc_html'));
        $this->twig->addFunction(new \Twig\TwigFunction('esc_attr', 'esc_attr'));
        $this->twig->addFunction(new \Twig\TwigFunction('esc_url', 'esc_url'));
    }

    /**
     * Include required files
     */
    private function includes() {
        // Note: Settings.php is NOT included here because it extends WC_Settings_Page
        // which isn't loaded until later. It's included in add_settings_page() instead.
        require_once WC_COMPOSABLE_PRODUCT_PATH . 'includes/Admin/Product_Data.php';
        require_once WC_COMPOSABLE_PRODUCT_PATH . 'includes/Product_Type.php';
        require_once WC_COMPOSABLE_PRODUCT_PATH . 'includes/Stock_Manager.php';
        require_once WC_COMPOSABLE_PRODUCT_PATH . 'includes/Cart_Handler.php';
        require_once WC_COMPOSABLE_PRODUCT_PATH . 'includes/Product_Selector.php';

        // Initialize components
        new Admin\Product_Data();
        new Cart_Handler();
    }

    /**
     * Add composable product type to selector
     *
     * @param array $types Product types
     * @return array
     */
    public function add_product_type($types) {
        $types['composable'] = __('Composable product', 'wc-composable-product');
        return $types;
    }

    /**
     * Use custom product class for composable products
     *
     * @param string $classname Product class name
     * @param string $product_type Product type
     * @return string
     */
    public function product_class($classname, $product_type) {
        if ($product_type === 'composable') {
            $classname = 'WC_Composable_Product\Product_Type';
        }
        return $classname;
    }

    /**
     * Enqueue frontend scripts and styles
     */
    public function enqueue_frontend_scripts() {
        if (is_product()) {
            wp_enqueue_style(
                'wc-composable-product',
                WC_COMPOSABLE_PRODUCT_URL . 'assets/css/frontend.css',
                [],
                WC_COMPOSABLE_PRODUCT_VERSION
            );

            wp_enqueue_script(
                'wc-composable-product',
                WC_COMPOSABLE_PRODUCT_URL . 'assets/js/frontend.js',
                ['jquery'],
                WC_COMPOSABLE_PRODUCT_VERSION,
                true
            );

            wp_localize_script('wc-composable-product', 'wcComposableProduct', [
                'ajax_url' => admin_url('admin-ajax.php'),
                'nonce' => wp_create_nonce('wc_composable_product_nonce'),
                'i18n' => [
                    'select_items' => __('Please select items', 'wc-composable-product'),
                    'max_items' => __('Maximum items selected', 'wc-composable-product'),
                    'min_items' => __('Please select at least one item', 'wc-composable-product'),
                ],
            ]);
        }
    }

    /**
     * Enqueue admin scripts and styles
     */
    public function enqueue_admin_scripts($hook) {
        if ('post.php' === $hook || 'post-new.php' === $hook) {
            global $post_type;
            if ('product' === $post_type) {
                wp_enqueue_style(
                    'wc-composable-product-admin',
                    WC_COMPOSABLE_PRODUCT_URL . 'assets/css/admin.css',
                    [],
                    WC_COMPOSABLE_PRODUCT_VERSION
                );

                wp_enqueue_script(
                    'wc-composable-product-admin',
                    WC_COMPOSABLE_PRODUCT_URL . 'assets/js/admin.js',
                    ['jquery', 'wc-admin-product-meta-boxes'],
                    WC_COMPOSABLE_PRODUCT_VERSION,
                    true
                );
            }
        }
    }

    /**
     * Add settings page to WooCommerce
     *
     * @param array $settings WooCommerce settings pages
     * @return array
     */
    public function add_settings_page($settings) {
        // Include Settings.php here, when WC_Settings_Page is guaranteed to be loaded
        require_once WC_COMPOSABLE_PRODUCT_PATH . 'includes/Admin/Settings.php';
        $settings[] = new Admin\Settings();
        return $settings;
    }

    /**
     * Get Twig environment
     *
     * @return \Twig\Environment
     */
    public function get_twig() {
        return $this->twig;
    }

    /**
     * Render a Twig template
     *
     * @param string $template Template name
     * @param array $context Template variables
     * @return string
     */
    public function render_template($template, $context = []) {
        return $this->twig->render($template, $context);
    }
}