import requests
import json


def upload_article_draft(access_token, title, content, cover_media_id, author, digest=None, show_cover_pic=1):
    """
    上传文章草稿到微信公众号草稿箱

    参数:
        access_token (str): 公众号的access_token
        title (str): 文章标题
        content (str): 文章内容（HTML格式）
        cover_media_id (str): 封面图片的media_id
        author (str): 作者
        digest (str, optional): 文章摘要，默认为None
        show_cover_pic (int, optional): 是否显示封面，0不显示，1显示，默认为1

    返回:
        str: 成功时返回草稿的media_id
        None: 失败时返回None
    """
    # 验证必填参数
    if not all([access_token, title, content, cover_media_id, author]):
        return None

    # 微信上传草稿接口
    url = f"https://api.weixin.qq.com/cgi-bin/draft/add?access_token={access_token}"

    # 构造请求数据
    article_data = {
        "articles": [
            {
                "title": title,
                "content": content,
                "thumb_media_id": cover_media_id,
                "author": author,
                "show_cover_pic": show_cover_pic
            }
        ]
    }

    # 添加可选参数
    if digest:
        article_data["articles"][0]["digest"] = digest

    try:
        # 发送POST请求
        response = requests.post(
            url,
            data=json.dumps(article_data, ensure_ascii=False).encode('utf-8'),
            headers={'Content-Type': 'application/json'},
            timeout=15
        )

        # 解析响应结果
        result = json.loads(response.text)

        # 检查是否有错误
        if "errcode" in result and result["errcode"] != 0:
            return None

        # 返回草稿的media_id
        media_id = result.get("media_id")
        if media_id:
            return media_id
        else:
            return None

    except requests.exceptions.RequestException:
        return None
    except json.JSONDecodeError:
        return None
    except Exception:
        return None