import requests
from lxml import etree


def mkdir(path):
    import os
    path = path.strip()
    path = path.rstrip('\\')

    isExists = os.path.exists(path)

    if not isExists:
        os.makedirs(path)
        print(path + '创建成功')
        return True
    else:
        print('目录已存在')
        return False


def get_cid():
    url = 'http://www.leleketang.com/let3/knowledges.php?grade_id=30'
    html = requests.get(url).text
    e = etree.HTML(html)
    global folders
    folders = e.xpath('//div[@class="cal_name"]/a[@data-step=0]/text()')[::-1]
    for folder in folders:
        mkdir(f'D:/乐乐课堂视频/{folder}')
    return e.xpath('//div[@class="cal_name"]/a[@data-step=0]/@data-cid')[::-1]


def download(url, fp, name):
    res = requests.get(url).content
    with open(fp + f'/{name}.mp4', 'wb') as f:
        f.write(res)


if __name__ == '__main__':
    max_page = 0
    for k, cid in enumerate(get_cid()):
        p = 1
        while 1:
            url = f'http://www.leleketang.com/let3/knowledge_list.php'
            params = {
                'cid': cid,
                'p': p,
            }
            res = requests.get(url, params=params).text
            e = etree.HTML(res)
            if p == 1:
                page_list = e.xpath('//a[@class="p_normal"]/text()')
                if page_list:
                    max_page = int(page_list[-1])
            # 每一页视频名字、链接列表
            names = e.xpath('//div[@class="knowledge_info"]/div/text()')
            urls = e.xpath('//div[@class="knowledge_btns"]/div/@data-video')
            for j, url in enumerate(urls):
                download(url, f'D:/乐乐课堂视频/{folders[k]}', names[j])
                print(f'{names[j]}          已下载完成！')
            print('-------------------------------------')
            print(f'第{p}页下载完成！\n')
            print('-------------------------------------')
            p += 1
            if not max_page or p > max_page:
                break