<?php
defined( 'ABSPATH' ) || exit;

class WVRD_Redeem {

    public static $lifetimes = array(
        'week'     => '周付',
        'month'    => '月付',
        'season'   => '季付',
        'halfyear' => '半年付',
        'year'     => '年付',
        'lifetime' => '终身',
    );

    /**
     * 生成兑换码
     */
    public static function generate_codes( $vip_type, $vip_lifetime, $count = 1, $expired_at = '', $remark = '' ) {
        global $wpdb;
        $table  = $wpdb->prefix . WVRD_TABLE;
        $codes  = array();
        $now    = current_time( 'mysql' );
        $exp    = $expired_at ? date( 'Y-m-d H:i:s', strtotime( $expired_at ) ) : null;

        for ( $i = 0; $i < intval( $count ); $i++ ) {
            $code = strtoupper( implode( '-', str_split( substr( md5( uniqid( mt_rand(), true ) ), 0, 16 ), 4 ) ) );
            $wpdb->insert( $table, array(
                'code'         => $code,
                'vip_type'     => $vip_type,
                'vip_lifetime' => $vip_lifetime,
                'status'       => 0,
                'expired_at'   => $exp,
                'remark'       => sanitize_text_field( $remark ),
                'created_at'   => $now,
            ) );
            $codes[] = $code;
        }
        return $codes;
    }

    /**
     * 兑换码核销，开通会员
     */
    public static function redeem( $code, $user_id ) {
        global $wpdb;
        $table = $wpdb->prefix . WVRD_TABLE;

        if ( ! $user_id ) {
            return new WP_Error( 'not_login', '请先登录后再兑换。' );
        }

        $row = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$table} WHERE code = %s LIMIT 1", strtoupper( trim( $code ) ) ) );

        if ( ! $row ) {
            return new WP_Error( 'invalid', '兑换码不存在，请检查后重试。' );
        }
        if ( (int) $row->status === 1 ) {
            return new WP_Error( 'used', '该兑换码已被使用。' );
        }
        if ( (int) $row->status === 2 ) {
            return new WP_Error( 'disabled', '该兑换码已被禁用。' );
        }
        if ( $row->expired_at && strtotime( $row->expired_at ) < time() ) {
            return new WP_Error( 'expired', '该兑换码已过期。' );
        }

        // 验证 vip_type 是否存在
        $vip_types = \WPCOM\Member\VIP::get_vip_types();
        if ( ! isset( $vip_types[ $row->vip_type ] ) ) {
            return new WP_Error( 'invalid_type', '兑换码对应的会员类型不存在，请联系管理员。' );
        }

        // 计算到期日
        $end_date = self::calc_end_date( $user_id, $row->vip_type, $row->vip_lifetime );

        // 写入用户 VIP 数据
        $begin_date = current_time( 'Y-m-d' );
        $current_end = get_user_option( 'vip_end_date', $user_id );
        if ( $current_end && strtotime( $current_end ) > time() ) {
            $begin_date = $current_end;
        }

        update_user_option( $user_id, 'vip_type', $row->vip_type );
        update_user_option( $user_id, 'vip_begin_date', $begin_date );
        update_user_option( $user_id, 'vip_end_date', $end_date );

        // 标记兑换码已使用
        $wpdb->update( $table, array(
            'status'  => 1,
            'used_by' => $user_id,
            'used_at' => current_time( 'mysql' ),
        ), array( 'id' => $row->id ) );

        $vip_title = $vip_types[ $row->vip_type ]['title'];
        $lifetime_label = isset( self::$lifetimes[ $row->vip_lifetime ] ) ? self::$lifetimes[ $row->vip_lifetime ] : $row->vip_lifetime;

        return array(
            'vip_title'    => $vip_title,
            'lifetime'     => $lifetime_label,
            'end_date'     => $end_date,
            'end_date_fmt' => date( 'Y年m月d日', strtotime( $end_date ) ),
        );
    }

    /**
     * 计算新到期日（支持叠加）
     */
    public static function calc_end_date( $user_id, $vip_type, $vip_lifetime ) {
        $current_type    = get_user_option( 'vip_type', $user_id );
        $current_end     = get_user_option( 'vip_end_date', $user_id );
        $base            = ( $current_type === $vip_type && $current_end && strtotime( $current_end ) > time() )
                           ? $current_end
                           : current_time( 'Y-m-d' );

        if ( $vip_lifetime === 'lifetime' ) {
            return '9999-12-31';
        }

        $map = array(
            'week'     => '+7 days',
            'month'    => '+1 month',
            'season'   => '+3 months',
            'halfyear' => '+6 months',
            'year'     => '+1 year',
        );

        $offset = isset( $map[ $vip_lifetime ] ) ? $map[ $vip_lifetime ] : '+1 month';
        return date( 'Y-m-d', strtotime( $offset, strtotime( $base ) ) );
    }

    /**
     * 获取兑换码列表（后台用）
     */
    public static function get_codes( $args = array() ) {
        global $wpdb;
        $table   = $wpdb->prefix . WVRD_TABLE;
        $where   = '1=1';
        $values  = array();

        if ( ! empty( $args['status'] ) && $args['status'] !== 'all' ) {
            $where   .= ' AND status = %d';
            $values[] = intval( $args['status'] );
        }
        if ( ! empty( $args['search'] ) ) {
            $where   .= ' AND code LIKE %s';
            $values[] = '%' . $wpdb->esc_like( $args['search'] ) . '%';
        }

        $per_page = isset( $args['per_page'] ) ? intval( $args['per_page'] ) : 20;
        $page     = isset( $args['page'] ) ? max( 1, intval( $args['page'] ) ) : 1;
        $offset   = ( $page - 1 ) * $per_page;

        $sql   = $values ? $wpdb->prepare( "SELECT * FROM {$table} WHERE {$where} ORDER BY id DESC LIMIT %d OFFSET %d", array_merge( $values, array( $per_page, $offset ) ) )
                         : "SELECT * FROM {$table} WHERE {$where} ORDER BY id DESC LIMIT {$per_page} OFFSET {$offset}";
        $total_sql = $values ? $wpdb->prepare( "SELECT COUNT(*) FROM {$table} WHERE {$where}", $values )
                             : "SELECT COUNT(*) FROM {$table} WHERE {$where}";

        return array(
            'items' => $wpdb->get_results( $sql ),
            'total' => (int) $wpdb->get_var( $total_sql ),
        );
    }

    /**
     * 更新兑换码状态
     */
    public static function update_status( $id, $status ) {
        global $wpdb;
        $table = $wpdb->prefix . WVRD_TABLE;
        return $wpdb->update( $table, array( 'status' => intval( $status ) ), array( 'id' => intval( $id ) ) );
    }

    /**
     * 删除兑换码
     */
    public static function delete_code( $id ) {
        global $wpdb;
        $table = $wpdb->prefix . WVRD_TABLE;
        return $wpdb->delete( $table, array( 'id' => intval( $id ) ) );
    }
}