// 从文本域解析图片URL，返回指定数量的不同随机图片URL
private function get_random_img_urls( $count = 1 ) {
    $raw = get_option( self::OPTION_IMG_URLS, '' );
    if ( empty( $raw ) ) return array();

    $lines = explode( "\n", $raw );
    $urls  = array();
    foreach ( $lines as $line ) {
        $url = trim( $line );
        if ( ! empty( $url ) ) {
            $urls[] = $url;
        }
    }
    
    if ( empty( $urls ) ) return array();
    
    // 打乱数组顺序，保证随机性
    shuffle( $urls );
    
    // 如果需要的数量大于可用数量，循环补充
    $result = array();
    $urlCount = count( $urls );
    for ( $i = 0; $i < $count; $i++ ) {
        $result[] = $urls[ $i % $urlCount ];
    }
    
    return $result;
}

// 单张随机图兼容方法（保留原有调用）
private function get_random_img_url() {
    $urls = $this->get_random_img_urls( 1 );
    return $urls ? $urls[0] : '';
}

private function process_post( $post_id, $source ) {
    $post = get_post( $post_id );
    if ( ! $post || 'publish' !== $post->post_status ) return;

    $content = (string)$post->post_content;
    $images  = $this->extract_image_urls( $content );

    // 文章无图片 → 中间插入图片（原有逻辑不变）
    if ( empty( $images ) ) {
        $new_img_url = $this->get_random_img_url();
        if ( empty( $new_img_url ) ) {
            $this->insert_log( array(
                'post_id'        => $post_id,
                'post_title'     => get_the_title( $post_id ),
                'status'         => 'failed',
                'reason'         => '未配置可用图片地址，无法新增图片',
                'image_count'    => 0,
                'broken_count'   => 0,
                'replaced_count' => 0,
                'old_urls'       => array(),
                'new_urls'       => array(),
                'run_source'     => $source
            ) );
            return;
        }

        $img_tag = '<p><img src="' . esc_url( $new_img_url ) . '" alt=""></p>';
        $content_len = mb_strlen( $content );
        $mid_pos     = (int)( $content_len / 2 );
        $new_content = mb_substr( $content, 0, $mid_pos ) . $img_tag . mb_substr( $content, $mid_pos );

        $updated = wp_update_post( array(
            'ID'           => $post_id,
            'post_content' => $new_content
        ), true );

        if ( is_wp_error( $updated ) ) {
            $this->insert_log( array(
                'post_id'        => $post_id,
                'post_title'     => get_the_title( $post_id ),
                'status'         => 'failed',
                'reason'         => '新增图片失败：' . $updated->get_error_message(),
                'image_count'    => 0,
                'broken_count'   => 0,
                'replaced_count' => 1,
                'old_urls'       => array(),
                'new_urls'       => array( $new_img_url ),
                'run_source'     => $source
            ) );
            return;
        }

        clean_post_cache( $post_id );
        $this->insert_log( array(
            'post_id'        => $post_id,
            'post_title'     => get_the_title( $post_id ),
            'status'         => 'add_image',
            'reason'         => '文章无图片，已在内容中间插入图片',
            'image_count'    => 1,
            'broken_count'   => 0,
            'replaced_count' => 1,
            'old_urls'       => array(),
            'new_urls'       => array( $new_img_url ),
            'run_source'     => $source
        ) );
        return;
    }

    // 检测失效图片（原有逻辑不变）
    $broken_urls = array();
    $reasons     = array();
    foreach ( $images as $url ) {
        $check = $this->is_image_url_valid( $url );
        if ( ! $check['valid'] ) {
            $broken_urls[] = $url;
            $reasons[]     = $url . ' => ' . $check['reason'];
        }
    }
    $broken_urls = array_values( array_unique( $broken_urls ) );

    if ( empty( $broken_urls ) ) {
        $this->insert_log( array(
            'post_id'        => $post_id,
            'post_title'     => get_the_title( $post_id ),
            'status'         => 'no_need',
            'reason'         => '所有图片均可正常访问',
            'image_count'    => count( $images ),
            'broken_count'   => 0,
            'replaced_count' => 0,
            'old_urls'       => array(),
            'new_urls'       => array(),
            'run_source'     => $source
        ) );
        return;
    }

    // 替换失效图片（核心修改部分）
    $new_content    = $content;
    $replace_map    = array();
    $replaced_count = 0;
    $failed_reason  = '';
    
    // 获取与失效图片数量匹配的随机备用图
    $rand_imgs = $this->get_random_img_urls( count( $broken_urls ) );

    if ( empty( $rand_imgs ) ) {
        $failed_reason = '未配置可用图片地址，无法替换';
    } else {
        // 为每个失效URL分配不同的备用图
        foreach ( $broken_urls as $index => $bad_url ) {
            $new_img = $rand_imgs[ $index ];
            if ( false !== strpos( $new_content, $bad_url ) ) {
                $new_content = str_replace( $bad_url, $new_img, $new_content );
                $replace_map[ $bad_url ] = $new_img;
                $replaced_count++;
            }
        }
    }

    if ( $failed_reason ) {
        $this->insert_log( array(
            'post_id'        => $post_id,
            'post_title'     => get_the_title( $post_id ),
            'status'         => 'failed',
            'reason'         => $failed_reason . '；失效明细：' . implode( '；', $reasons ),
            'image_count'    => count( $images ),
            'broken_count'   => count( $broken_urls ),
            'replaced_count' => $replaced_count,
            'old_urls'       => $broken_urls,
            'new_urls'       => $replace_map,
            'run_source'     => $source
        ) );
        return;
    }

    if ( $new_content === $content || $replaced_count <= 0 ) {
        $this->insert_log( array(
            'post_id'        => $post_id,
            'post_title'     => get_the_title( $post_id ),
            'status'         => 'failed',
            'reason'         => '检测到失效图片，但未能完成替换；失效明细：' . implode( '；', $reasons ),
            'image_count'    => count( $images ),
            'broken_count'   => count( $broken_urls ),
            'replaced_count' => 0,
            'old_urls'       => $broken_urls,
            'new_urls'       => $replace_map,
            'run_source'     => $source
        ) );
        return;
    }

    $updated = wp_update_post( array(
        'ID'           => $post_id,
        'post_content' => $new_content
    ), true );

    if ( is_wp_error( $updated ) ) {
        $this->insert_log( array(
            'post_id'        => $post_id,
            'post_title'     => get_the_title( $post_id ),
            'status'         => 'failed',
            'reason'         => '文章更新失败：' . $updated->get_error_message(),
            'image_count'    => count( $images ),
            'broken_count'   => count( $broken_urls ),
            'replaced_count' => 0,
            'old_urls'       => $broken_urls,
            'new_urls'       => $replace_map,
            'run_source'     => $source
        ) );
        return;
    }

    clean_post_cache( $post_id );
    $this->insert_log( array(
        'post_id'        => $post_id,
        'post_title'     => get_the_title( $post_id ),
        'status'         => 'success',
        'reason'         => '已替换失效图片；失效明细：' . implode( '；', $reasons ),
        'image_count'    => count( $images ),
        'broken_count'   => count( $broken_urls ),
        'replaced_count' => $replaced_count,
        'old_urls'       => $broken_urls,
        'new_urls'       => $replace_map,
        'run_source'     => $source
    ) );
}<br />
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