import random

from retrying import retry
import requests
from loguru import logger
from proxypool.setting import GET_TIMEOUT


class BaseCrawler(object):
    urls = []

    @property
    def user_agent(self):
        """
        return an User-Agent at random
        :return:
        """
        ua_list = [
            'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.101',
            'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.122',
            'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71',
            'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95',
            'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.71',
            'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)',
            'Mozilla/5.0 (Windows NT 5.1; U; en; rv:1.8.1) Gecko/20061208 Firefox/2.0.0 Opera 9.50',
            'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0',
        ]
        return random.choice(ua_list)

    @property
    def header(self):
        """
        basic header
        :return:
        """
        return {'User-Agent': self.user_agent,
                'Accept': '*/*',
                'Connection': 'keep-alive',
                'Accept-Language': 'zh-CN,zh;q=0.8'}

    @retry(stop_max_attempt_number=3, retry_on_result=lambda x: x is None, wait_fixed=2000)
    def fetch(self, url, **kwargs):
        try:
            kwargs.setdefault('timeout', GET_TIMEOUT)
            kwargs.setdefault('verify', False)
            response = requests.get(url,headers=self.header, **kwargs)
            if response.status_code == 200:
                response.encoding = 'utf-8'
                return response.text
        except requests.ConnectionError:
            return
    
    @logger.catch
    def crawl(self):
        """
        crawl main method
        """
        for url in self.urls:
            logger.info(f'fetching {url}')
            html = self.fetch(url)
            for proxy in self.parse(html):
                logger.info(f'fetched proxy {proxy.string()} from {url}')
                yield proxy