<?php
/**
 * Simple Deposits for WooCommerce — Init / Loader
 *
 * Single entry point. Checks for WooCommerce, shows an admin notice
 * and bails safely if it's missing/inactive, otherwise wires up the
 * rest of the plugin's classes.
 *
 * @package Simple_Deposits_For_WooCommerce
 */

defined( 'ABSPATH' ) || exit;

final class SDFW_Init {

    /**
     * Singleton instance.
     */
    private static ?SDFW_Init $instance = null;

    /**
     * Settings page controller.
     *
     * @var \SDFW_Settings|null
     */
    public $settings = null;

    /**
     * Per-product field controller.
     *
     * @var \SDFW_Product_Field|null
     */
    public $product_field = null;

    /**
     * Single product page deposit badge controller.
     *
     * @var \SDFW_Product_Badge|null
     */
    public $product_badge = null;

    /**
     * Deposit / full-payment toggle controller. Renders above the
     * payment method list at checkout and applies the resolved split
     * to whichever eligible gateway (bKash, Nagad, etc.) the customer
     * actually chooses — see class-sdfw-gateway.php for the full flow.
     *
     * @var \SDFW_Gateway|null
     */
    public $gateway = null;

    /**
     * Cart/checkout display controller.
     *
     * @var \SDFW_Cart|null
     */
    public $cart = null;

    /**
     * Order admin/meta/email controller.
     *
     * @var \SDFW_Order|null
     */
    public $order = null;

    /**
     * Get (and lazily create) the single instance.
     */
    public static function instance(): SDFW_Init {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    /**
     * Private constructor — use instance().
     */
    private function __construct() {
        $this->init();
    }

    /**
     * Boot sequence.
     */
    private function init(): void {

        // No manual textdomain loading here — this plugin's text domain
        // (aawahid-simple-deposits-for-woocommerce) matches its WordPress.org
        // slug, so WordPress automatically loads the correct translation
        // for every string as needed (has done since WP 4.6). Calling
        // load_plugin_textdomain() ourselves is redundant and is flagged
        // by Plugin Check as a discouraged function, so it's intentionally
        // not present anywhere in this plugin.
        if ( ! $this->is_woocommerce_active() ) {
            add_action( 'admin_notices', [ $this, 'woocommerce_missing_notice' ] );
            return;
        }

        $this->wire_modules();

        add_action( 'admin_enqueue_scripts', [ $this, 'enqueue_admin_assets' ] );
        add_action( 'wp_enqueue_scripts', [ $this, 'enqueue_frontend_assets' ] );
    }

    /**
     * Enqueue admin-only CSS. Scoped to product edit screens and the
     * WooCommerce settings screen so it never loads site-wide.
     */
    public function enqueue_admin_assets( string $hook ): void {

        $screen = function_exists( 'get_current_screen' ) ? get_current_screen() : null;

        $is_product_screen = $screen && in_array( $screen->id, [ 'product', 'edit-product' ], true );

        // Read-only check of which admin screen we're on, purely to decide
        // whether to enqueue a stylesheet — no data is processed or
        // persisted, so there's nothing here for a nonce to protect.
        // phpcs:ignore WordPress.Security.NonceVerification.Recommended, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- read-only screen check, no state change; sanitized via sanitize_text_field()+wp_unslash() below regardless.
        $page = isset( $_GET['page'] ) ? sanitize_text_field( wp_unslash( $_GET['page'] ) ) : '';
        // phpcs:ignore WordPress.Security.NonceVerification.Recommended, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- read-only screen check, no state change; sanitized via sanitize_text_field()+wp_unslash() below regardless.
        $tab = isset( $_GET['tab'] ) ? sanitize_text_field( wp_unslash( $_GET['tab'] ) ) : '';

        $is_wc_settings = ( 'wc-settings' === $page && 'sdfw_deposits' === $tab );

        if ( $is_wc_settings ) {
            wp_enqueue_script(
                'sdfw-admin',
                SDFW_URL . 'assets/js/admin.js',
                [],
                SDFW_VERSION,
                true
            );
        }

        if ( ! $is_product_screen && ! $is_wc_settings ) {
            return;
        }

        wp_enqueue_style(
            'sdfw-admin',
            SDFW_URL . 'assets/css/admin.css',
            [],
            SDFW_VERSION
        );
    }

    /**
     * Enqueue frontend assets.
     *
     * frontend.css is shared by three independent features — the
     * single product page deposit badge (SDFW_Product_Badge), the
     * cart/checkout deposit breakdown rows (SDFW_Cart), and the
     * checkout payment-mode toggle (SDFW_Gateway) — so it loads on all
     * three page types. product-badge.js and its localised variation
     * amounts are only ever relevant on the single product page, so
     * those stay scoped to is_product() alone. frontend.js (the
     * payment-mode toggle's checkout-refresh trigger) is scoped to
     * is_checkout() alone for the same reason.
     */
    public function enqueue_frontend_assets(): void {

        $is_product  = function_exists( 'is_product' ) && is_product();
        $is_cart     = function_exists( 'is_cart' ) && is_cart();
        $is_checkout = function_exists( 'is_checkout' ) && is_checkout();

        if ( ! $is_product && ! $is_cart && ! $is_checkout ) {
            return;
        }

        wp_enqueue_style(
            'sdfw-frontend',
            SDFW_URL . 'assets/css/frontend.css',
            [],
            SDFW_VERSION
        );

        if ( $is_checkout ) {
            // No explicit 'jquery' dependency: frontend.js only reads
            // jQuery off the global if WooCommerce's own checkout
            // script has already loaded it on this page.
            wp_enqueue_script(
                'sdfw-payment-mode-toggle',
                SDFW_URL . 'assets/js/frontend.js',
                [],
                SDFW_VERSION,
                true
            );
        }

        if ( ! $is_product ) {
            return;
        }

        // No explicit 'jquery' dependency: product-badge.js only reads
        // jQuery off the global if WooCommerce's own variation-form
        // script has already loaded it on this page.
        wp_enqueue_script(
            'sdfw-product-badge',
            SDFW_URL . 'assets/js/product-badge.js',
            [],
            SDFW_VERSION,
            true
        );

        $current_product = null;

        if ( isset( $GLOBALS['product'] ) && $GLOBALS['product'] instanceof WC_Product ) {
            $current_product = $GLOBALS['product'];
        } elseif ( function_exists( 'get_the_ID' ) ) {
            $current_product = wc_get_product( get_the_ID() );
        }

        $variation_amounts = [];

        if ( $current_product instanceof WC_Product && $current_product->is_type( 'variable' ) ) {
            foreach ( $current_product->get_children() as $variation_id ) {
                // Pre-formatted (via sdfw_format_price()) so the JS can
                // drop the string straight into the badge without
                // reimplementing WooCommerce's currency formatting.
                $variation      = wc_get_product( $variation_id );
                $variation_amounts[ $variation_id ] = sdfw_format_price(
                    sdfw_get_product_amount( $variation_id, $variation ? (float) $variation->get_price() : null )
                );
            }
        }

        wp_localize_script( 'sdfw-product-badge', 'sdfw_variation_amounts', $variation_amounts );
    }

    /**
     * Check WooCommerce is active and loaded. Mirrors the theme's
     * fd_wc_active() defensive pattern so this plugin never fatals
     * if WooCommerce is toggled off.
     */
    public function is_woocommerce_active(): bool {
        return class_exists( 'WooCommerce' );
    }

    /**
     * Admin notice shown when WooCommerce is missing/inactive.
     * Plugin otherwise does nothing — no fatals, no partial behavior.
     */
    public function woocommerce_missing_notice(): void {

        if ( ! current_user_can( 'activate_plugins' ) ) {
            return;
        }

        $message = sprintf(
            /* translators: %s: plugin name */
            esc_html__( '%s requires WooCommerce to be installed and active. The plugin is currently inactive.', 'aawahid-simple-deposits-for-woocommerce' ),
            '<strong>' . esc_html__( 'Simple Deposits for WooCommerce', 'aawahid-simple-deposits-for-woocommerce' ) . '</strong>'
        );

        echo '<div class="notice notice-error"><p>' . wp_kses_post( $message ) . '</p></div>';
    }

    /**
     * Instantiate the feature classes. Only reached when WooCommerce
     * is confirmed active.
     */
    private function wire_modules(): void {

        // The CORRECT way to register a custom WC_Settings_Page tab:
        // hook into 'woocommerce_get_settings_pages', include the class
        // file there (WC_Settings_Page is guaranteed to exist at that
        // point), instantiate, and return the instance as part of the
        // pages array. WooCommerce collects all settings pages through
        // this filter before building the tab list — anything wired
        // outside this filter simply never appears.
        add_filter( 'woocommerce_get_settings_pages', [ $this, 'register_settings_page' ] );

        if ( class_exists( 'SDFW_Product_Field' ) ) {
            $this->product_field = new SDFW_Product_Field();
        }

        if ( class_exists( 'SDFW_Product_Badge' ) ) {
            $this->product_badge = new SDFW_Product_Badge();
        }

        // Not a WC_Payment_Gateway (see class-sdfw-gateway.php docblock),
        // so unlike the old version of this class it doesn't need a
        // WooCommerce-owned filter to instantiate it. The class file
        // itself loads eagerly via the main plugin bootstrap's include
        // loader now, so it's just wired up directly here.
        if ( class_exists( 'SDFW_Gateway' ) ) {
            $this->gateway = new SDFW_Gateway();
        }

        // Not yet built (see project blueprint §3.7 / §3.9) — guarded the
        // same way as the controllers above so wiring these in later is
        // just a matter of adding the class file, no further changes here.
        if ( class_exists( 'SDFW_Cart' ) ) {
            $this->cart = new SDFW_Cart();
        }

        if ( class_exists( 'SDFW_Order' ) ) {
            $this->order = new SDFW_Order();
        }
    }

    /**
     * Load, instantiate, and return our settings page inside the
     * 'woocommerce_get_settings_pages' filter. WC_Settings_Page is
     * guaranteed to exist here because WooCommerce includes its admin
     * class files before firing this filter.
     *
     * @param array $pages Existing WC settings page instances.
     * @return array
     */
    public function register_settings_page( array $pages ): array {

        $settings_file = SDFW_DIR . 'includes/class-sdfw-settings.php';

        if ( file_exists( $settings_file ) ) {
            require_once $settings_file;
        }

        if ( class_exists( 'SDFW_Settings' ) ) {
            $this->settings = new SDFW_Settings();
            $pages[]        = $this->settings;
        }

        return $pages;
    }

    // Prevent cloning and unserialization of the singleton.
    private function __clone() {}
    public function __wakeup() {
        throw new \Exception( 'Cannot unserialize a singleton.' );
    }
}