import concurrent.futures
import re
from typing import List, Optional

import requests
from bs4 import BeautifulSoup

from model.news import News
from pageextractor.util import get_extractor
from searchpageextractor.SearchPageExtractor import SearchPageExtractor


class SogouSearchPageExtractor(SearchPageExtractor):
    _search_base_url = "https://www.sogou.com/sogou?interation=1728053249&query={}"
    _next_page_base_url = "https://www.sogou.com/sogou"
    _base_url = "https://www.sogou.com"
    _request_headers = {"User-Agent":
                            "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) "
                            "Chrome/94.0.4606.61 Safari/537.36"}

    def search_by_keyword(self, keyword: str, max_page: int) -> List[News]:
        all_item_links = self._get_all_item_links(keyword, max_page)
        search_result = []

        with concurrent.futures.ThreadPoolExecutor() as executor:
            futures = []
            for link in all_item_links:
                page_extractor = get_extractor(link)
                if page_extractor is None:
                    continue
                futures.append(executor.submit(page_extractor.get_news))
            for future in concurrent.futures.as_completed(futures):
                r = future.result()
                if r is not None:
                    search_result.append(r)
        return search_result

    def _get_all_item_links(self, keyword: str, max_page: int) -> List[str]:
        url_list = []
        current_page = 1
        search_page = self._get_search_page(keyword)
        item_urls = self._get_item_urls(search_page)
        url_list.extend(item_urls)
        next_page_url = self._get_next_page_url(search_page)

        while next_page_url is not None and current_page < max_page:
            search_page = self._get_search_page_by_url(next_page_url)
            item_urls = self._get_item_urls(search_page)
            url_list.extend(item_urls)
            next_page_url = self._get_next_page_url(search_page)
            current_page += 1
        return url_list

    def _get_search_url(self, keyword: str) -> str:
        return self._search_base_url.format(keyword)

    def _get_search_page(self, keyword: str) -> BeautifulSoup:
        search_url = self._get_search_url(keyword)
        return self._get_search_page_by_url(search_url)

    def _get_search_page_by_url(self, url: str) -> BeautifulSoup:
        r = requests.get(url, headers=self._request_headers)

        if r.encoding == 'ISO-8859-1':
            encodings = requests.utils.get_encodings_from_content(r.text)
            if encodings:
                encoding = encodings[0]
            else:
                encoding = r.apparent_encoding
            encode_content = r.content.decode(encoding, 'ignore')
        else:
            encode_content = r.text
        soup = BeautifulSoup(encode_content, features="lxml")
        return soup

    def _get_next_page_url(self, soup: BeautifulSoup) -> Optional[str]:
        selector = "a#sogou_next"
        next_page_tag = soup.select_one(selector)
        if next_page_tag is None:
            return None
        return self._next_page_base_url + next_page_tag["href"]

    def _get_item_urls(self, soup: BeautifulSoup) -> List[str]:
        selector = "div.vrwrap h3.vr-title>a"
        item_links = soup.select(selector)
        result_urls = []

        with concurrent.futures.ThreadPoolExecutor() as executor:
            futures = [executor.submit(convert_url, self._base_url + link["href"]) for link in item_links]
            for future in concurrent.futures.as_completed(futures):
                result = future.result()
                if result is not None:
                    result_urls.append(result)
        return result_urls


def convert_url(source_url: str):
    r = requests.get(source_url)
    if r.encoding == 'ISO-8859-1':
        encodings = requests.utils.get_encodings_from_content(r.text)
        if encodings:
            encoding = encodings[0]
        else:
            encoding = r.apparent_encoding
        encode_content = r.content.decode(encoding, 'ignore')
    else:
        encode_content = r.text
    soup = BeautifulSoup(encode_content, features="lxml")
    script_str = soup.select_one("script").decode_contents()
    return extract_redirect_url(script_str)


def extract_redirect_url(script: str):
    pattern = re.compile("window\\.location\\.replace\\(\"(.*)\"\\)")
    result = re.search(pattern, script)
    if result is None:
        return None
    return result.group(1)