<?php
namespace DigiDiscount;

defined( 'ABSPATH' ) || exit;

final class Cart {
    const CODE = 'digidiscount-auto';
    private static $instance;
    public array $result = array( 'discounts' => array(), 'rules' => array(), 'shipping' => false, 'gifts' => array() );
    private array $limits = array();
    private bool $running = false;

    public static function instance(): self {
        if ( ! self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    private function __construct() {
        add_action( 'woocommerce_before_calculate_totals', array( $this, 'calculate' ), 90 );
        add_filter( 'woocommerce_get_shop_coupon_data', array( $this, 'coupon_data' ), 10, 2 );
        add_filter( 'woocommerce_coupon_get_discount_type', static fn( $type, $coupon ) => self::CODE === $coupon->get_code() ? 'digidiscount' : $type, 10, 2 );
        add_filter( 'woocommerce_coupon_is_valid_for_cart', array( $this, 'coupon_cart' ), 10, 2 );
        add_filter( 'woocommerce_coupon_get_discount_amount', array( $this, 'discount' ), 10, 5 );
        add_filter( 'woocommerce_coupon_get_items_to_apply', array( $this, 'available' ), 10, 3 );
        add_filter( 'woocommerce_coupon_custom_discounts_array', array( $this, 'precise' ), 10, 2 );
        add_filter( 'woocommerce_cart_totals_coupon_label', array( $this, 'label' ), 10, 2 );
        add_filter( 'woocommerce_cart_totals_coupon_html', array( $this, 'coupon_html' ), 10, 3 );
        add_action( 'woocommerce_checkout_create_order', array( $this, 'snapshot' ), 20 );
        add_action( 'woocommerce_store_api_checkout_order_processed', array( $this, 'snapshot_store' ), 20 );
        add_action( 'woocommerce_single_product_summary', array( $this, 'product_message' ), 25 );
        add_action( 'woocommerce_before_cart', array( $this, 'message' ) );
        add_action( 'woocommerce_before_checkout_form', array( $this, 'message' ) );
        add_action( 'wp_enqueue_scripts', array( $this, 'assets' ) );
        if ( did_action( 'woocommerce_blocks_loaded' ) ) {
            $this->blocks();
        } else {
            add_action( 'woocommerce_blocks_loaded', array( $this, 'blocks' ) );
        }
    }

    public static function lines( $cart ): array {
        $factor = 10 ** wc_get_price_decimals();
        $out = array();
        foreach ( $cart->get_cart() as $key => $item ) {
            $product = $item['data'];
            $cats = wc_get_product_term_ids( $item['product_id'], 'product_cat' );
            foreach ( $cats as $cat ) {
                $cats = array_merge( $cats, get_ancestors( $cat, 'product_cat', 'taxonomy' ) );
            }
            $price = wc_prices_include_tax() ? wc_get_price_including_tax( $product, array( 'qty' => $item['quantity'] ) ) : (float) $product->get_price() * $item['quantity'];
            $out[ $key ] = array(
                'key' => $key, 'product_id' => $item['product_id'], 'variation_id' => $item['variation_id'] ?? 0,
                'qty' => (float) $item['quantity'], 'total' => (int) round( $price * $factor ),
                'categories' => array_unique( array_map( 'intval', $cats ) ), 'sale' => $product->is_on_sale(),
                'tags' => wc_get_product_term_ids( $item['product_id'], 'product_tag' ),
                'brands' => taxonomy_exists( 'product_brand' ) ? wc_get_product_term_ids( $item['product_id'], 'product_brand' ) : array(),
                'gift' => ! empty( $item['dd_gift'] ),
            );
        }
        return $out;
    }

    public static function context( $cart ): array {
        $coupons = array_values( array_diff( $cart->get_applied_coupons(), array( self::CODE ) ) );
        $user = wp_get_current_user();
        return apply_filters( 'digidiscount_cart_context', array(
            'currency' => get_woocommerce_currency(), 'now' => time(), 'coupons' => $coupons,
            'user_id' => $user->ID, 'roles' => $user->roles,
            'gateway' => WC()->session ? WC()->session->get( 'chosen_payment_method', '' ) : '',
        ), $cart );
    }

    public function calculate( $cart ): void {
        if ( $this->running || ( is_admin() && ! wp_doing_ajax() ) ) {
            return;
        }
        $this->running = true;
        try {
            if ( ! has_action( 'digidiscount_sync_gifts' ) ) {
                foreach ( $cart->get_cart() as $key => $item ) {
                    if ( ! empty( $item['dd_gift'] ) ) {
                        $cart->remove_cart_item( $key );
                    }
                }
            }
            $context = self::context( $cart );
            $blocked = ! wc_coupons_enabled();
            foreach ( $context['coupons'] as $code ) {
                $coupon = new \WC_Coupon( $code );
                $blocked = $blocked || $coupon->get_individual_use();
            }
            $rules = $blocked ? array() : Rules::runtime();
            $this->result = Engine::calculate( self::lines( $cart ), $rules, $context, get_option( 'digidiscount_mode', 'best' ) );
            do_action( 'digidiscount_sync_gifts', $cart, $this->result );
            $codes = $context['coupons'];
            if ( array_sum( $this->result['discounts'] ) > 0 ) {
                $codes[] = self::CODE;
            }
            $cart->set_applied_coupons( $codes );
            if ( WC()->session ) {
                WC()->session->set( 'digidiscount_shipping', $this->result['shipping'] );
            }
        } finally {
            $this->running = false;
        }
    }

    public function coupon_data( $data, $code ) {
        if ( self::CODE !== strtolower( $code ) ) {
            return $data;
        }
        if ( ! WC()->cart ) {
            return false;
        }
        return array( 'id' => 0, 'code' => self::CODE, 'discount_type' => 'fixed_cart', 'amount' => 0, 'individual_use' => false, 'virtual' => true );
    }

    public function coupon_cart( $valid, $coupon ) {
        return self::CODE === $coupon->get_code() ? true : $valid;
    }

    public function available( $items, $coupon, $discounts ) {
        if ( self::CODE === $coupon->get_code() ) {
            $this->limits = array();
            $used = $discounts->get_discounts_by_item( true );
            foreach ( $items as $item ) {
                $this->limits[ $item->key ] = max( 0, (int) round( $item->price - ( $used[ $item->key ] ?? 0 ) ) );
            }
        }
        return $items;
    }

    public function discount( $discount, $amount, $item, $single, $coupon ) {
        if ( self::CODE !== $coupon->get_code() || ! is_array( $item ) ) {
            return $discount;
        }
        $value = ( $this->result['discounts'][ $item['key'] ?? '' ] ?? 0 ) / ( 10 ** wc_get_price_decimals() );
        return min( (float) $amount, $single ? $value / max( 1, (float) $item['quantity'] ) : $value );
    }

    public function precise( $discounts, $coupon ) {
        if ( self::CODE === $coupon->get_code() ) {
            foreach ( $discounts as $key => $value ) {
                $discounts[ $key ] = min( $this->limits[ $key ] ?? 0, $this->result['discounts'][ $key ] ?? 0 );
            }
        }
        return $discounts;
    }

    public function label( $label, $coupon ) {
        return self::CODE === $coupon->get_code() ? __( 'Automatic savings', 'digidiscount' ) : $label;
    }

    public function coupon_html( $html, $coupon, $discount ) {
        return self::CODE === $coupon->get_code() ? wp_kses_post( $discount ) : $html;
    }

    public function snapshot( $order ): void {
        if ( $this->result['rules'] ) {
            $order->update_meta_data( '_digidiscount_campaigns', $this->result['rules'] );
            $order->update_meta_data( '_digidiscount_version', DIGIDISCOUNT_VERSION );
        }
    }

    public function snapshot_store( $order ): void {
        $this->snapshot( $order );
        $order->save();
    }

    public function message(): void {
        if ( ! WC()->cart ) {
            return;
        }
        $message = apply_filters( 'digidiscount_cart_message', '', Rules::runtime(), self::lines( WC()->cart ), self::context( WC()->cart ) );
        if ( $message ) {
            echo '<div class="dd-store-notice" role="status">' . esc_html( $message ) . '</div>';
        }
    }

    public function product_message(): void {
        global $product;
        if ( ! $product instanceof \WC_Product ) {
            return;
        }
        $cats = wc_get_product_term_ids( $product->get_id(), 'product_cat' );
        foreach ( $cats as $cat ) {
            $cats = array_merge( $cats, get_ancestors( $cat, 'product_cat', 'taxonomy' ) );
        }
        $line = array( 'product_id' => $product->get_id(), 'variation_id' => 0, 'categories' => $cats, 'sale' => $product->is_on_sale() );
        foreach ( Rules::runtime() as $rule ) {
            if ( array_key_exists( 'show_single', $rule ) || ! $rule['enabled'] || ! $rule['message'] || ! Engine::eligible( $line, $rule ) || ( $rule['start'] && time() < $rule['start'] ) || ( $rule['end'] && time() >= $rule['end'] ) ) {
                continue;
            }
            if ( ! apply_filters( 'digidiscount_public_message_visible', true, $rule ) ) {
                continue;
            }
            echo '<div class="dd-store-notice">' . esc_html( $rule['message'] ) . '</div>';
        }
        do_action( 'digidiscount_product_tables', $product );
    }

    public function assets(): void {
        if ( is_product() || is_cart() || is_checkout() ) {
            wp_enqueue_style( 'digidiscount-store', plugins_url( 'assets/store.css', DIGIDISCOUNT_FILE ), array(), DIGIDISCOUNT_VERSION );
        }
        if ( ( is_cart() || is_checkout() ) && wp_script_is( 'wc-blocks-checkout', 'registered' ) ) {
            wp_enqueue_script( 'digidiscount-blocks', plugins_url( 'assets/blocks.js', DIGIDISCOUNT_FILE ), array( 'wc-blocks-checkout', 'wp-data', 'wp-element', 'wp-plugins', 'wp-i18n' ), DIGIDISCOUNT_VERSION, true );
            wp_set_script_translations( 'digidiscount-blocks', 'digidiscount' );
        }
    }

    public function blocks(): void {
        if ( function_exists( 'woocommerce_store_api_register_endpoint_data' ) ) {
            woocommerce_store_api_register_endpoint_data( array(
                'endpoint' => \Automattic\WooCommerce\StoreApi\Schemas\V1\CartSchema::IDENTIFIER,
                'namespace' => 'digidiscount',
                'data_callback' => static function () {
                    return array( 'message' => WC()->cart ? apply_filters( 'digidiscount_cart_message', '', Rules::runtime(), self::lines( WC()->cart ), self::context( WC()->cart ) ) : '' );
                },
                'schema_callback' => static fn() => array( 'message' => array( 'description' => 'Campaign progress', 'type' => 'string', 'readonly' => true ) ),
                'schema_type' => ARRAY_A,
            ) );
        }
    }
}