<?php
/**
 * AKSRT Rebate — 返佣系统
 *
 * 管理订单返佣、推广返佣记录。
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

class AKSRT_Rebate {

    private static $instance = null;

    const TYPE_ORDER  = 'order';
    const TYPE_invite = 'invite';

    const STATUS_PENDING  = 'pending';
    const STATUS_SETTLED  = 'settled';
    const STATUS_CANCELLED = 'cancelled';

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

    private function table(): string {
        return AKSRT_DB_Migrator::table('rebate_log');
    }

    /**
     * 创建返佣记录
     */
    public function create(array $data): int {
        global $wpdb;

        $user_id        = (int) ($data['user_id'] ?? 0);
        $order_number   = sanitize_text_field((string) ($data['order_number'] ?? ''));
        $source_user_id = (int) ($data['source_user_id'] ?? 0);
        $amount         = (float) ($data['amount'] ?? 0);
        $type           = sanitize_key((string) ($data['type'] ?? self::TYPE_ORDER));
        $note           = sanitize_textarea_field((string) ($data['note'] ?? ''));

        if ($user_id <= 0 || $amount <= 0) {
            return 0;
        }

        $valid_types = [self::TYPE_ORDER, self::TYPE_invite];
        if (!in_array($type, $valid_types, true)) {
            $type = self::TYPE_ORDER;
        }

        $result = $wpdb->insert($this->table(), [
            'user_id'        => $user_id,
            'order_number'   => $order_number,
            'source_user_id' => $source_user_id > 0 ? $source_user_id : null,
            'amount'         => $amount,
            'type'           => $type,
            'status'         => self::STATUS_PENDING,
            'created_at'     => current_time('mysql'),
            'note'           => $note,
        ]);

                $id = $result ? (int) $wpdb->insert_id : 0;
        if ($id > 0) {
            do_action('aksrt_pay_rebate_added', $user_id, $amount, [
                'rebate_id'     => $id,
                'order_number'  => $order_number,
                'type'          => $type,
            ]);
        }
        return $id;
    }

    /**
     * 结算返佣
     */
    public function settle(int $id): bool {
        global $wpdb;

        $row = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$this->table()} WHERE id = %d AND status = %s",
            $id, self::STATUS_PENDING
        ), ARRAY_A);

        if (!$row) return false;

        $user_id = (int) $row['user_id'];
        $amount  = (float) $row['amount'];

        $result = $wpdb->update($this->table(), [
            'status'     => self::STATUS_SETTLED,
            'settled_at' => current_time('mysql'),
        ], ['id' => $id]);

        if ($result && class_exists('AKSRT_Credits')) {
            AKSRT_Credits::add($user_id, (int) $amount, 'rebate', [
                'ref_type' => 'rebate',
                'ref_id'   => $id,
            ]);
        }

        return (bool) $result;
    }

    /**
     * 取消返佣
     */
    public function cancel(int $id): bool {
        global $wpdb;
        return (bool) $wpdb->update($this->table(), [
            'status' => self::STATUS_CANCELLED,
        ], ['id' => $id, 'status' => self::STATUS_PENDING]);
    }

    /**
     * 获取返佣列表
     */
    public function get_list(array $args = []): array {
        global $wpdb;

        $limit  = max(1, min(100, (int) ($args['limit'] ?? 20)));
        $offset = max(0, (int) ($args['offset'] ?? 0));
        $status = sanitize_key((string) ($args['status'] ?? ''));
        $user_id = (int) ($args['user_id'] ?? 0);

        $where = [];
        $params = [];

        if ($status !== '') {
            $where[] = 'status = %s';
            $params[] = $status;
        }
        if ($user_id > 0) {
            $where[] = 'user_id = %d';
            $params[] = $user_id;
        }

        $where_sql = $where ? 'WHERE ' . implode(' AND ', $where) : '';

        $count_sql = "SELECT COUNT(*) FROM {$this->table()} {$where_sql}";
        $total = $params ? (int) $wpdb->get_var($wpdb->prepare($count_sql, $params)) : (int) $wpdb->get_var($count_sql);

        $sql = "SELECT * FROM {$this->table()} {$where_sql} ORDER BY created_at DESC LIMIT %d OFFSET %d";
        $params[] = $limit;
        $params[] = $offset;

        $items = $wpdb->get_results($wpdb->prepare($sql, $params), ARRAY_A);

        return [
            'items'     => $items ?: [],
            'total'     => $total,
            'page'      => floor($offset / $limit) + 1,
            'max_pages' => ceil($total / $limit),
        ];
    }

    /**
     * 获取统计
     */
    public function get_stats(): array {
        global $wpdb;
        $table = $this->table();

        $row = $wpdb->get_row(
            "SELECT
                COUNT(*) as total,
                SUM(CASE WHEN status = 'pending' THEN 1 ELSE 0 END) as pending,
                SUM(CASE WHEN status = 'settled' THEN 1 ELSE 0 END) as settled,
                SUM(amount) as total_amount,
                SUM(CASE WHEN status = 'settled' THEN amount ELSE 0 END) as settled_amount
            FROM {$table}",
            ARRAY_A
        );

        return [
            'total'          => (int) ($row['total'] ?? 0),
            'pending'        => (int) ($row['pending'] ?? 0),
            'settled'        => (int) ($row['settled'] ?? 0),
            'total_amount'   => (float) ($row['total_amount'] ?? 0),
            'settled_amount' => (float) ($row['settled_amount'] ?? 0),
        ];
    }
}