<?php
/**
 * AKSRT Shop Term Meta
 *
 * 为商品分类（aksrt_product_cat）、商品标签（aksrt_product_tag）和
 * 优惠活动（shop_discount）注册 term meta 并提供 getter/setter。
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

class AKSRT_Shop_Term_Meta {

    private static $instance = null;

    /** @var string Meta key for product_cat/product_tag unified storage */
    const META_KEY = 'aksrt_shop_term_meta';

    /** @var string Meta key for shop_discount unified storage */
    const DISCOUNT_META_KEY = 'aksrt_shop_discount_meta';

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

    /**
     * Register hooks.
     */
    public function init(): void {
        add_action('init', [$this, 'register_discount_taxonomy'], 5);
        add_action('init', [$this, 'register_term_meta_fields'], 10);
    }

    // ─── Taxonomy Registration ───────────────────────────────────

    /**
     * Register the shop_discount taxonomy for discount campaigns.
     */
    public function register_discount_taxonomy(): void {
        if (taxonomy_exists('shop_discount')) {
            return;
        }

        $shop_enabled = true;
        if (class_exists('AKSRT_Settings')) {
            $shop_settings = AKSRT_Settings::get_shop_settings();
            $shop_enabled  = !empty($shop_settings['enabled']);
        }
        $shop_show_ui   = true;
        $shop_show_menu = is_admin() ? $shop_enabled : false;

        register_taxonomy('shop_discount', 'aksrt_product', [
            'labels'            => [
                'name'          => __('优惠活动', 'aksrt'),
                'singular_name' => __('优惠活动', 'aksrt'),
                'search_items'  => __('搜索优惠活动', 'aksrt'),
                'all_items'     => __('所有优惠活动', 'aksrt'),
                'edit_item'     => __('编辑优惠活动', 'aksrt'),
                'add_new_item'  => __('新增优惠活动', 'aksrt'),
                'menu_name'     => __('优惠活动', 'aksrt'),
            ],
            'public'            => true,
            'hierarchical'      => false,
            'show_ui'           => $shop_show_ui,
            'show_in_menu'      => $shop_show_menu,
            'show_in_rest'      => true,
            'show_admin_column' => true,
            'rewrite'           => ['slug' => 'shop-discount', 'with_front' => false],
        ]);
    }

    // ─── Term Meta Registration ──────────────────────────────────

    /**
     * Register all term meta fields for REST API exposure.
     */
    public function register_term_meta_fields(): void {
        $auth = function () {
            return current_user_can('manage_categories');
        };

        // ── aksrt_product_cat ──
        $cat_fields = $this->get_cat_field_definitions();
        foreach ($cat_fields as $key => $def) {
            register_term_meta('aksrt_product_cat', $key, [
                'type'              => $def['type'],
                'description'       => $def['description'] ?? $key,
                'single'            => true,
                'default'           => $def['default'] ?? '',
                'show_in_rest'      => true,
                'sanitize_callback' => $def['sanitize'] ?? 'sanitize_text_field',
                'auth_callback'     => $auth,
            ]);
        }

        // ── aksrt_product_tag ──
        $tag_fields = $this->get_tag_field_definitions();
        foreach ($tag_fields as $key => $def) {
            register_term_meta('aksrt_product_tag', $key, [
                'type'              => $def['type'],
                'description'       => $def['description'] ?? $key,
                'single'            => true,
                'default'           => $def['default'] ?? '',
                'show_in_rest'      => true,
                'sanitize_callback' => $def['sanitize'] ?? 'sanitize_text_field',
                'auth_callback'     => $auth,
            ]);
        }

        // ── shop_discount ──
        $discount_fields = $this->get_discount_field_definitions();
        foreach ($discount_fields as $key => $def) {
            register_term_meta('shop_discount', $key, [
                'type'              => $def['type'],
                'description'       => $def['description'] ?? $key,
                'single'            => true,
                'default'           => $def['default'] ?? '',
                'show_in_rest'      => true,
                'sanitize_callback' => $def['sanitize'] ?? 'sanitize_text_field',
                'auth_callback'     => $auth,
            ]);
        }
    }

    // ─── Field Definitions ───────────────────────────────────────

    /**
     * Product category term meta field definitions.
     *
     * @return array<string, array{type:string, description:string, default:mixed, sanitize?:callable}>
     */
    private function get_cat_field_definitions(): array {
        return [
            'shop_cat_limit_buy' => [
                'type' => 'integer', 'description' => '分类级限购 (-1 不限)', 'default' => -1,
                'sanitize' => function ($v) { return max(-1, min(9999, (int) $v)); },
            ],
            'shop_cat_shipping_fee' => [
                'type' => 'string', 'description' => '分类级运费类型', 'default' => '',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['', 'free', 'fixed', 'amount'], true) ? $v : '';
                },
            ],
            'shop_cat_guest_buy' => [
                'type' => 'string', 'description' => '分类级免登录购买', 'default' => '',
            ],
            'shop_cat_email_fill' => [
                'type' => 'string', 'description' => '分类级邮箱必留', 'default' => '',
            ],
            'shop_cat_after_sale' => [
                'type' => 'string', 'description' => '分类级售后政策', 'default' => '',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['', 'refund', 'refund_return', 'none'], true) ? $v : '';
                },
            ],
            'shop_cat_rebate' => [
                'type' => 'string', 'description' => '分类级返佣覆盖', 'default' => '',
            ],
            'shop_cat_service' => [
                'type' => 'string', 'description' => '分类级服务保障', 'default' => '',
                'sanitize' => 'sanitize_textarea_field',
            ],
            'shop_cat_single_tab' => [
                'type' => 'string', 'description' => '分类级自定义 TAB', 'default' => '',
                'sanitize' => 'sanitize_textarea_field',
            ],
            'shop_cat_content_after' => [
                'type' => 'string', 'description' => '分类级详情页底部内容', 'default' => '',
                'sanitize' => 'wp_kses_post',
            ],
            'shop_cat_content_layout' => [
                'type' => 'string', 'description' => '分类级内容布局', 'default' => '',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['', 'adapt', 'full', 'sidebar'], true) ? $v : '';
                },
            ],
            'shop_cat_content_show_bg' => [
                'type' => 'string', 'description' => '分类级详情背景盒子', 'default' => '',
            ],
            'shop_cat_list_style' => [
                'type' => 'string', 'description' => '分类页列表样式', 'default' => '',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['', 'default', 'card-lg', 'card-sm'], true) ? $v : '';
                },
            ],
        ];
    }

    /**
     * Product tag term meta field definitions.
     *
     * @return array<string, array{type:string, description:string, default:mixed, sanitize?:callable}>
     */
    private function get_tag_field_definitions(): array {
        return [
            'shop_tag_priority' => [
                'type' => 'integer', 'description' => '标签优先级（影响显示顺序）', 'default' => 0,
                'sanitize' => function ($v) { return max(0, min(9999, (int) $v)); },
            ],
            'shop_tag_class' => [
                'type' => 'string', 'description' => '标签颜色 class', 'default' => '',
                'sanitize' => 'sanitize_html_class',
            ],
            'shop_tag_is_important' => [
                'type' => 'string', 'description' => '重点标签（商品价格位着重显示）', 'default' => '',
            ],
        ];
    }

    /**
     * Shop discount term meta field definitions.
     *
     * @return array<string, array{type:string, description:string, default:mixed, sanitize?:callable}>
     */
    private function get_discount_field_definitions(): array {
        return [
            'shop_discount_small_badge' => [
                'type' => 'string', 'description' => '小标签文案', 'default' => '',
            ],
            'shop_discount_priority' => [
                'type' => 'integer', 'description' => '优先级（数字越大越优先）', 'default' => 0,
                'sanitize' => function ($v) { return max(0, min(9999, (int) $v)); },
            ],
            'shop_discount_is_important' => [
                'type' => 'string', 'description' => '重点活动', 'default' => '',
            ],
            'shop_discount_important_class' => [
                'type' => 'string', 'description' => '重点活动背景色 class', 'default' => '',
                'sanitize' => 'sanitize_html_class',
            ],
            'shop_discount_scope' => [
                'type' => 'string', 'description' => '优惠范围', 'default' => 'item',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['item', 'product', 'author', 'order'], true) ? $v : 'item';
                },
            ],
            'shop_discount_type' => [
                'type' => 'string', 'description' => '优惠类型', 'default' => 'reduction',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['reduction', 'discount', 'gift'], true) ? $v : 'reduction';
                },
            ],
            'shop_discount_value' => [
                'type' => 'string', 'description' => '优惠数值（立减金额/折扣 0.01-9.99）', 'default' => '0',
                'sanitize' => function ($v) { return sanitize_text_field((string) $v); },
            ],
            'shop_discount_gift_config' => [
                'type' => 'string', 'description' => '赠品配置 JSON', 'default' => '',
                'sanitize' => 'sanitize_textarea_field',
            ],
            'shop_discount_price_limit' => [
                'type' => 'string', 'description' => '金额门槛', 'default' => '0',
                'sanitize' => function ($v) { return max(0, (float) $v); },
            ],
            'shop_discount_user_limit' => [
                'type' => 'string', 'description' => '用户身份限制', 'default' => '',
                'sanitize' => function ($v) {
                    $v = sanitize_key((string) $v);
                    return in_array($v, ['', 'vip', 'vip_2', 'auth'], true) ? $v : '';
                },
            ],
            'shop_discount_start' => [
                'type' => 'string', 'description' => '活动开始时间', 'default' => '',
                'sanitize' => 'sanitize_text_field',
            ],
            'shop_discount_end' => [
                'type' => 'string', 'description' => '活动结束时间', 'default' => '',
                'sanitize' => 'sanitize_text_field',
            ],
            'shop_discount_countdown' => [
                'type' => 'string', 'description' => '倒计时显示', 'default' => '',
            ],
        ];
    }

    // ─── Getters ─────────────────────────────────────────────────

    /**
     * Get all shop term meta for a product category.
     *
     * @param int $term_id
     * @return array
     */
    public static function get_cat_meta(int $term_id): array {
        $defaults = [
            'limit_buy'     => -1,
            'shipping_fee'  => '',
            'guest_buy'     => '',
            'email_fill'    => '',
            'after_sale'    => '',
            'rebate'        => '',
            'service'       => '',
            'single_tab'    => '',
            'content_after' => '',
            'content_layout' => '',
            'content_show_bg' => '',
            'list_style'    => '',
        ];

        $result = [];
        foreach ($defaults as $key => $default) {
            $meta_key = "shop_cat_{$key}";
            $val = get_term_meta($term_id, $meta_key, true);
            $result[$key] = ($val !== '' && $val !== false) ? $val : $default;
        }

        return $result;
    }

    /**
     * Get all shop term meta for a product tag.
     *
     * @param int $term_id
     * @return array
     */
    public static function get_tag_meta(int $term_id): array {
        $priority = get_term_meta($term_id, 'shop_tag_priority', true);
        $class = get_term_meta($term_id, 'shop_tag_class', true);
        $is_important = get_term_meta($term_id, 'shop_tag_is_important', true);

        return [
            'priority'     => $priority !== '' ? (int) $priority : 0,
            'class'        => is_string($class) ? $class : '',
            'is_important' => !empty($is_important),
        ];
    }

    /**
     * Get all shop discount term meta.
     *
     * @param int $term_id
     * @return array
     */
    public static function get_discount_meta(int $term_id): array {
        $defaults = [
            'small_badge'     => '',
            'priority'        => 0,
            'is_important'    => false,
            'important_class' => '',
            'scope'           => 'item',
            'type'            => 'reduction',
            'value'           => '0',
            'gift_config'     => '',
            'price_limit'     => '0',
            'user_limit'      => '',
            'start'           => '',
            'end'             => '',
            'countdown'       => '',
        ];

        $result = [];
        foreach ($defaults as $key => $default) {
            $meta_key = "shop_discount_{$key}";
            $val = get_term_meta($term_id, $meta_key, true);
            $result[$key] = ($val !== '' && $val !== false) ? $val : $default;
        }

        $result['priority'] = (int) $result['priority'];
        $result['is_important'] = !empty($result['is_important']);
        $result['price_limit'] = (float) $result['price_limit'];

        return $result;
    }

    /**
     * Resolve parameter inheritance: product → category → theme settings.
     *
     * Returns the effective value for a given parameter key by checking:
     * 1. Product-level override (from post meta)
     * 2. Category-level override (from term meta)
     * 3. Theme-level default (from AKSRT_Settings::get_shop_settings())
     *
     * @param int    $product_id Product post ID
     * @param string $param_key  Parameter key (e.g. 'limit_buy', 'shipping_fee')
     * @param mixed  $product_value Product-level value (null if not set)
     * @return mixed
     */
    public static function resolve_inheritance(int $product_id, string $param_key, $product_value = null) {
        // 1. Product-level override
        if ($product_value !== null && $product_value !== '' && $product_value !== -1) {
            return $product_value;
        }

        // 2. Category-level override
        $terms = get_the_terms($product_id, 'aksrt_product_cat');
        if (is_array($terms) && !empty($terms)) {
            $cat_meta_key = "shop_cat_{$param_key}";
            foreach ($terms as $term) {
                $val = get_term_meta($term->term_id, $cat_meta_key, true);
                if ($val !== '' && $val !== false && $val !== -1) {
                    return $val;
                }
            }
        }

        // 3. Theme-level default
        $shop = AKSRT_Settings::get_shop_settings();
        $defaults = $shop['product_defaults'] ?? [];
        return $defaults[$param_key] ?? $product_value;
    }
}