import base64
import hashlib
import logging
import os
import re
import uuid
from urllib.parse import urljoin
import requests


def get_img_tag_url(img_tag):

    # 提取图片url的正则表达式模式
    pattern = r'\!\[.*?\]\((.*?)\)'
    # 找到第一个匹配的链接
    match = re.search(pattern, img_tag)
    if not match:
        return ""

    # 获取匹配到的链接
    link = match.group(1)
    # 第0个为链接
    link = link.split(" ")[0]
    return link


# 填充img标签中的图片链接
# img_tag  '![1](http://wiki.jxbw.com/hdwiki/uploads/202303/1679471232U4iPCjtm_s.jpg "1")'
# img_tag  '![1](uploads/202303/1679471232U4iPCj6tm_s.jpg "1")'
def fill_img_url(img_tag):
    """
    填充img标签中的图片链接。

    参数:
    img_tag (str): 原始的img标签

    返回:
    tuple: 修改后的img标签和图片的完整链接
    """
    # 一个完整的img标签内删除换行符
    img_tag = img_tag.replace("\n", "")
    link = get_img_tag_url(img_tag)
    if len(link) == 0:
        return img_tag, ''

    base_url = os.getenv("IMG_URL_PREFIX")
    if "http:" in link:
        # 图片为全链接，不替换
        return img_tag, link
    elif base_url:
        # 补全图片链接
        full_link = urljoin(base_url, link)
        img_tag = img_tag.replace(link, full_link)
        return img_tag, full_link
    else:
        return img_tag, ''


def download_picture(img_tag, download_path):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) '
                      'Chrome/94.0.4606.71 Safari/537.36 '
    }
    img_tag, img_url = fill_img_url(img_tag)
    if img_url == '':
        return img_tag
    # if "_s" in img_tag:
    #     breakpoint()
    file_name = img_url.split("/")[-1]
    file_path = os.path.normpath(download_path + "\\" + file_name)
    file_path = file_path.replace("\\", "/")

    # 文件已经存在时不下载
    if not os.path.exists(file_path):
        img_date = requests.get(url=img_url, headers=headers).content
        logging.info(f"图片下载成功：{img_url}")
        with open(file_path, 'wb') as fp:
            fp.write(img_date)

    # img_tag中的url替换为下载的图片路径
    return img_tag.replace(img_url, file_path)


def download_picture_from_other_url(img_tag, download_path):
    headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) '
                      'Chrome/94.0.4606.71 Safari/537.36 '
    }
    img_tag, img_url = fill_img_url(img_tag)
    # if "_s" in img_tag:
    #     breakpoint()
    file_name = uuid.uuid4()
    file_path = os.path.join(download_path, f"{file_name}.png")
    file_path = os.path.normpath(file_path)
    # 文件已经存在时不下载
    if not os.path.exists(file_path):
        try:
            img_date = requests.get(url=img_url, headers=headers).content
            with open(file_path, 'wb') as fp:
                fp.write(img_date)
            logging.info(f"图片下载成功：{img_url}")
        except Exception as e:
            logging.warning(f"img download error url:{img_url}")
            return img_tag

    # img_tag中的url替换为下载的图片路径
    return img_tag.replace(img_url, file_path)


def extract_base64_from_data_uri(data_uri):
    # 分割字符串以找到 base64 部分
    parts = data_uri.split(',')
    if len(parts) == 2 and parts[0].endswith('base64'):
        # 移除后缀并返回 base64 值
        return parts[1][:-1]
    else:
        return None


def picture_base64(img_tag, picture_save_path):
    # 解码Base64字符串
    # ![](data:image/png;base64,1679471232U4iPCj6tm_s)
    base64_str = extract_base64_from_data_uri(img_tag)
    if picture_save_path is None or picture_save_path == "":
        return "![picture](空)"
    # 将图片内容做MD5 用作文件名
    hash_object = hashlib.md5()
    hash_object.update(base64_str.encode())
    img_md5 = hash_object.hexdigest()

    picture_save_path = picture_save_path + "\\%s.png" % img_md5
    picture_save_path = os.path.normpath(picture_save_path)
    picture_save_path = picture_save_path.replace("\\", "/")

    # 文件已经存在时不重新保存
    if not os.path.exists(picture_save_path):
        decoded_string = base64.b64decode(base64_str)
        with open(picture_save_path, 'wb') as fp:
            fp.write(decoded_string)

    # 修改img_tab的图片路径
    match = re.search("\[(.*?)\]", img_tag)
    result = ""
    if match:
        result = match.group(1)
    if result == "":
        return "![picture](%s)" % picture_save_path
    else:
        return "![%s](%s \"%s\")" % (result, picture_save_path, result)


def process_img_tag(str_img_tag, img_path):
    # 如果img标签指向的是本地磁盘路径 则忽略该标签返回空
    if "file:///" in str_img_tag:
        logging.warning(f"存在非法的链接地址：{str_img_tag}")
        return ""
    if img_path is None or img_path == "":
        return "![picture](空)"
    
    img_url = get_img_tag_url(str_img_tag)
    if "data:image/png;base64" in str_img_tag:
        return picture_base64(str_img_tag, img_path)
    # (4696等存在指向外部链接的 img标签。 暂时保留不删除)
    elif "http://" in str_img_tag or "https://" in str_img_tag:
        return download_picture_from_other_url(str_img_tag, img_path)
    elif not img_url.startswith("http"):
        return download_picture(str_img_tag, img_path)
    else:
        logging.warning(f"未处理的图片标签：{str_img_tag}")
        return str_img_tag