import requests
import re
import os
class reptile:
    def __init__(self,key_word,num):
        #b站的搜索关键词
        self.key_word = key_word
        #需要爬取的视频链接的个数
        self.num = num
        #b站综合排序的翻页的页数
        self.page = 1
        #浏览器访问的标头，防止访问被拒绝
        self.headers = {
            'Accept-Encoding':'gzip, deflate, br',
            'Accept-Language':'zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6',
            'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36 Edg/117.0.2045.60',
            'Cookie':"buvid3=294A4FDA-B28B-E848-02AF-4CC85F21E60591171infoc; b_nut=1719198491; _uuid=81083F39F-D9B8-E9C6-F81E-10DC77867B7C691969infoc; enable_web_push=DISABLE; buvid4=C6405F50-B303-58B0-92EB-FC0454BFDAEF92810-024062403-BZe5%2BJpTiegiNfU4N%2B1JIg%3D%3D; buvid_fp=723bec487c6799b3457440aa4e151029; header_theme_version=CLOSE; CURRENT_FNVAL=4048; SESSDATA=c2d43fe3%2C1734787697%2Ce83be%2A61CjCuaG1-EyZeMtp2_27iesQNI-S-Cm9CylwH3d1egMq6ECCdB1iVx2W84e9xdpWrnHgSVk5mSVNJZU1ibHNqYXFiNHlCckNEWS1wSEFwZ2ZkX0lRa1NVWFBhdDQ4WExRLUJjdGdURy1YVHRudm9OTFlrb0JkSFVZMXNVSW1ZYTRndEF1ZHNkcTZBIIEC; bili_jct=f9658d85c4fff75f379bafb9d8640c84; DedeUserID=3493115639892125; DedeUserID__ckMd5=c9eb7af8c9ebf568; rpdid=|(u))kkY|mm)0J'u~umkJl~R); is-2022-channel=1; bili_ticket=eyJhbGciOiJIUzI1NiIsImtpZCI6InMwMyIsInR5cCI6IkpXVCJ9.eyJleHAiOjE3MjYyMzcxNjgsImlhdCI6MTcyNTk3NzkwOCwicGx0IjotMX0.QLV_A_4RlS1JqNtyCErEjqyFnEVNNA4LpW9Ea78HJyg; bili_ticket_expires=1726237108; home_feed_column=5; browser_resolution=1653-834; bsource=search_baidu; bmg_af_switch=1; bmg_src_def_domain=i0.hdslb.com; sid=57thd76i; b_lsid=D3749D16_191E5E181D7; bp_t_offset_3493115639892125=976252148054491136",
        }
        self.base_url = 'https:'
        #对收集的弹幕的临时文件的路径
        self.path = f"./关于b站视频{self.key_word}的弹幕.txt"


    def get_video_url(self):
        '''
        获取网页综合排序当中的视频的详情页面连接
        '''
        url_list = []
        cnt = 0
        #b站综合排序的网页地址
        while cnt < self.num:
            url = f'https://search.bilibili.com/all?keyword={self.key_word}&from_source=webtop_search&spm_id_from=333.1007&search_source=2&page={self.page}'
            res = requests.get(url=url,headers=self.headers)
            #网页无法访问情况要错误跳出
            if res.status_code != 200:
                url_list = res.status_code
                break
            #获取html代码
            html = res.text
            #正则化表达解析html，获取视频超链接的详情页的地址列表
            reg_exp = 'video-list.*?a.*?href="(.*?)"'
            result = re.findall(reg_exp,html,re.S)
            #给list去重，去除重复的数据
            url_list = url_list+result
            url_list = list(set(url_list))
            #下一次循环访问下一页
            self.page += 1

            cnt = len(url_list)
            
        url_list = url_list[0:self.num]
        return url_list

    def bullet_chat(self,url):
        '''
        获取详情页面的弹幕列表
        '''
        if self.base_url not in url:
            url = self.base_url +url
        res = requests.get(url,headers=self.headers)
        # reg = 'bui-long-list-item'
        #解析xml内部包含的弹幕池的cid
        reg_find_bullet_cid = 'window.__INITIAL_STATE__.*?"cid":([0-9]*)'
        bullet_cid = re.findall(reg_find_bullet_cid,res.text,re.S)[0]
        #弹幕池的网页
        bullet_url = f'https://comment.bilibili.com/{bullet_cid}.xml'
        bullet_xml = requests.get(bullet_url,headers=self.headers)
        #弹幕中文需要的编码格式
        bullet_xml.encoding = 'utf-8'
        #解析弹幕池当中的弹幕内容
        reg_find_bullet_content = '<d p=.*?>(.*?)</d>'
        bullet_list = re.findall(reg_find_bullet_content,bullet_xml.text)
        return bullet_list

    def save_bullet(self,bullet_list):
        with open(self.path,'a',encoding='utf-8') as f:
            bullet = '\n'.join(bullet_list)
            f.write(bullet)
    
    def get_dataset(self):
        if os.path.exists(self.path):
            print("文件已存在即将进行覆盖")
            os.remove(self.path)
        print('正在爬取弹幕......')
        url_list = self.get_video_url()
        for url in url_list:
            bullet_list = self.bullet_chat(url)
            self.save_bullet(bullet_list)
        print("爬取弹幕成功")
        return self.path

if __name__ == '__main__':
    reptile = reptile('2024年巴黎运动会AI应用',300)
    reptile.get_dataset()