#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import time
import requests
from retry import retry
from .logger import logger
from concurrent import futures
from concurrent.futures import ALL_COMPLETED
from concurrent.futures import ThreadPoolExecutor

userAgent = (  # default user agent
    'Mozilla/5.0 (Windows NT 10.0; Win64; x64) '
    'AppleWebKit/537.36 (KHTML, like Gecko) '
    'Chrome/106.0.0.0 Safari/537.36 Edg/106.0.1370.47'
)


@retry(tries = 10, delay = 2, logger = None)
def httpRequest(url: str, proxy: str = '') -> bytes:  # fetch raw html content
    proxyStr = '' if proxy == '' else ' (via %s)' % proxy
    logger.debug('Http request `%s`%s' % (url, proxyStr))
    proxy = None if proxy == '' else proxy  # empty string -> None
    request = requests.get(
        url, timeout = 10,  # timeout -> 10s
        proxies = {  # request via socks or http proxy
            'http': proxy,
            'https': proxy
        },
        headers = {
            'user-agent': userAgent,  # with fake user-agent
            'accept-encoding': 'gzip, deflate',  # allow content compress
        }
    )
    if request.status_code not in range(200, 300):  # http status code 2xx
        raise RuntimeError('Http request failed')
    return request.content


def htmlSave(url: str, file: str, proxy: str = '') -> bool:  # save html content
    logger.debug('Html fetch `%s` -> `%s`' % (url, file))
    try:
        content = httpRequest(url, proxy)  # http request
    except:
        logger.debug('Html fetch failed -> `%s`' % url)
        return False  # request failed
    logger.debug('Html fetch success -> `%s`' % url)
    try:
        with open(file, 'wb') as fileObj:  # save html content
            fileObj.write(content)
    except:
        logger.debug('Html save failed -> `%s`' % file)
        return False  # save failed
    logger.debug('Html save success -> `%s`' % file)
    return True


def pageFetch(info: dict, delay: float, proxy: str = ''):  # fetch html content into file
    logger.debug('Page fetch: `%s` -> `%s`' % (info['url'], info['file']))
    if htmlSave(info['url'], info['file'], proxy):  # save html content
        logger.info('Page fetch success -> `%s`' % info['url'])
    else:
        logger.error('Page fetch failed -> `%s`' % info['url'])
    time.sleep(delay)


def htmlFetch(page, thread: int = 1, delay: float = 1, proxy: str = ''):  # fetch html with generator
    logger.info('Start html fetch process (thread = %d, delay = %f)' % (thread, delay))
    if proxy != '':
        logger.info('Html fetch proxy -> `%s`' % proxy)
    threadPool = ThreadPoolExecutor(max_workers = thread)
    threads = []
    while True:  # traverse generator
        try:
            threads.append(threadPool.submit(pageFetch, next(page), delay, proxy))  # add task
        except StopIteration:
            break
    futures.wait(threads, return_when = ALL_COMPLETED)  # wait all task complete
    logger.info('Html fetch complete')