import math

import re

from concurrent.futures import ThreadPoolExecutor

import requests

import lxml

import lxml.etree

# 获取网页源代码

def getHtml(url, header):

    try:

        response = requests.get(url, headers=header)

        response.raise_for_status()

        return response.content.decode('utf-8')

    except:

        return ''

# 获取翻页url

def getPageUrl(url, response):

    mytree = lxml.etree.HTML(response)

    # 页码

    carNum = mytree.xpath('//*[@id="post"]/p[3]/text()')[0]

    carNum = math.ceil(int(re.findall('(\d+)', carNum)[0]) / 40)

    urlList = url.rsplit('/', maxsplit=1)

    pageUrlList = []

    if carNum != 0:

        for i in range(1, carNum + 1):

            pageUrl = urlList[0] + "/o" + str(i) + "/" + urlList[1]

            pageUrlList.append(pageUrl)

    return pageUrlList

# 获取汽车品牌

def getCarBrand(response):

    mytree = lxml.etree.HTML(response)

    # 汽车品牌url

    carBrandUrl = mytree.xpath('//div[@class="dd-all clearfix js-brand js-option-hid-info"]/ul/li/p/a/@href')

    # 汽车品牌名

    carBrandName = mytree.xpath('//div[@class="dd-all clearfix js-brand js-option-hid-info"]/ul/li/p/a/text()')

    carBrandDict = {}

    for i in range(len(carBrandName)):

        carBrandDict[carBrandName[i]] = "https://www.guazi.com" + carBrandUrl[i]

    return carBrandDict

# 获取汽车信息

def getCarInfo(pageUrl, carBrandName):

    response = getHtml(pageUrl, header)

    mytree = lxml.etree.HTML(response)

    for i in range(40):

        # 汽车名称

        carName = mytree.xpath('//ul[@class="carlist clearfix js-top"]/li/a/h2/text()')[i]

        # 汽车图片

        carPic = mytree.xpath('//ul[@class="carlist clearfix js-top"]/li/a/img/@src')[i]

        carPic = carPic.rsplit("jpg", maxsplit=1)[0] + 'jpg'

        # 汽车出产年份、里程数

        carInfo = mytree.xpath('//ul[@class="carlist clearfix js-top"]/li/a/div[1]/text()')[i]

        # 现价

        carCurrentPrice = mytree.xpath('//ul[@class="carlist clearfix js-top"]/li/a/div[2]/p/text()')[i] + "万"

        # 原价

        carOriginPrice = mytree.xpath('//ul[@class="carlist clearfix js-top"]/li/a/div[2]/em/text()')[i]

        print(carName, carPic, carInfo, carCurrentPrice, carOriginPrice)

        # 写入文件

        path = carBrandName + '.txt'

        with open(path, 'a+') as f:

            f.write(str((carName, carPic, carInfo, carCurrentPrice, carOriginPrice)) + '\n')

if __name__ == '__main__':

    url = 'https://www.guazi.com/gz/buy/'

    header = {

        "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.85 Safari/537.36",

    }

    # 获得初始页源代码

    html = getHtml(url, header)

    # 获取汽车品牌信息字典

    carBrandDict = getCarBrand(html)

    # 多线程(10条的线程池)

    with ThreadPoolExecutor(10) as exT:

        # 程序执行流程

        # 根据汽车品牌进行爬取

        for carBrandName, carBrandUrl in carBrandDict.items():

            # 获取不同品牌页面源代码

            html = getHtml(carBrandUrl, header)

            # 获取当前品牌页面的页码url

            pageUrlList = getPageUrl(carBrandUrl, html)

            # 翻页

            for pageUrl in pageUrlList:

                # 获取汽车信息并写入文件

                exT.submit(getCarInfo, pageUrl, carBrandName)