import asyncio
import os
import os.path
from typing import List

import aiohttp
from bs4 import BeautifulSoup, SoupStrainer, Tag
from lingua import LanguageDetector

from app.locale import Locale, native_to_locale
from app.pipeline import Extractor as BaseExtractor
from app.pipeline import Fetcher as BaseFetcher
from app.pipeline import Pipeline as BasePipeline
from app.types import Site, Title

# The number of pages we will at most iterate through. This number was
# determined by going to https://lichess.org/coach/all/all/alphabetical
# and traversing to the last page.
MAX_PAGES = 162

# How long to wait between each network request.
SLEEP_SECS = 5


class Fetcher(BaseFetcher):
    def __init__(self, session: aiohttp.ClientSession):
        super().__init__(site=Site.LICHESS, session=session)

    async def scrape_usernames(self, page_no: int) -> List[str] | None:
        if page_no > MAX_PAGES:
            return []

        print(f"{self.site.value}: Scraping page {page_no}/{MAX_PAGES}")

        filepath = self.path_page_file(page_no)
        try:
            with open(filepath, "r") as f:
                return [line.strip() for line in f.readlines()]
        except FileNotFoundError:
            pass

        if self.has_made_request:
            await asyncio.sleep(SLEEP_SECS)

        url = f"https://lichess.org/coach/all/all/alphabetical?page={page_no}"
        response, status_code = await self.fetch(url)
        if response is None:
            return None  # Skips this page.

        usernames = []
        soup = BeautifulSoup(response, "lxml")
        members = soup.find_all("article", class_="coach-widget")
        for member in members:
            a = member.find("a", class_="overlay")
            if a:
                href = a.get("href")
                username = href[len("/coach/") :]
                usernames.append(username)

        with open(filepath, "w") as f:
            for username in usernames:
                f.write(f"{username}\n")

        return usernames

    async def download_user_files(self, username: str) -> None:
        maybe_download = [
            (
                f"https://lichess.org/coach/{username}",
                self.path_coach_file(username, f"{username}.html"),
            ),
            (
                f"https://lichess.org/@/{username}",
                self.path_coach_file(username, "stats.html"),
            ),
        ]

        to_download = []
        for d_url, d_filename in maybe_download:
            if os.path.isfile(d_filename):
                continue
            to_download.append((d_url, d_filename))

        if not to_download:
            return

        if self.has_made_request:
            await asyncio.sleep(SLEEP_SECS)

        await asyncio.gather(
            *[self._download_file(url=d[0], filename=d[1]) for d in to_download]
        )

    async def _download_file(self, url: str, filename: str) -> None:
        response, _unused_status = await self.fetch(url)
        if response is not None:
            with open(filename, "w") as f:
                f.write(response)


def _profile_filter(elem: Tag | str | None, attrs={}) -> bool:
    if "coach-widget" in attrs.get("class", ""):
        return True
    return False


def _stats_filter(elem: Tag | str | None, attrs={}) -> bool:
    if "user-link" in attrs.get("class", ""):
        return True
    if "profile-side" in attrs.get("class", ""):
        return True
    if "sub-ratings" in attrs.get("class", ""):
        return True
    return False


class Extractor(BaseExtractor):
    def __init__(self, fetcher: BaseFetcher, detector: LanguageDetector, username: str):
        super().__init__(fetcher, detector, username)

        self.profile_soup = None
        try:
            filename = self.fetcher.path_coach_file(username, f"{username}.html")
            with open(filename, "r") as f:
                self.profile_soup = BeautifulSoup(
                    f.read(), "lxml", parse_only=SoupStrainer(_profile_filter)
                )
        except FileNotFoundError:
            pass

        self.stats_soup = None
        try:
            filename = self.fetcher.path_coach_file(username, "stats.html")
            with open(filename, "r") as f:
                self.stats_soup = BeautifulSoup(
                    f.read(), "lxml", parse_only=SoupStrainer(_stats_filter)
                )
        except FileNotFoundError:
            pass

    def get_name(self) -> str | None:
        if self.stats_soup is None:
            return None
        profile_side = self.stats_soup.find("div", class_="profile-side")
        if not isinstance(profile_side, Tag):
            return None
        user_infos = profile_side.find("div", class_="user-infos")
        if not isinstance(user_infos, Tag):
            return None
        name = user_infos.find("strong", class_="name")
        if not isinstance(name, Tag):
            return None
        return name.get_text().strip()

    def get_image_url(self) -> str | None:
        if self.profile_soup is None:
            return None
        picture = self.profile_soup.find("img", class_="picture")
        if not isinstance(picture, Tag):
            return None
        src = picture.get("src", "")
        if not isinstance(src, str):
            return None
        if "image.lichess1.org" not in src:
            return None
        return src

    def get_title(self) -> Title | None:
        if self.stats_soup is None:
            return None
        utitle = self.stats_soup.find("span", class_="utitle")
        if not isinstance(utitle, Tag):
            return None
        title = utitle.get_text().strip()
        try:
            return Title(title)
        except ValueError:
            return None

    def get_languages(self) -> List[Locale] | None:
        if self.profile_soup is None:
            return None
        tr = self.profile_soup.find("tr", class_="languages")
        if not isinstance(tr, Tag):
            return None
        td = tr.find("td")
        if not isinstance(td, Tag):
            return None

        codes = []
        for lang in [s.strip() for s in tr.get_text().split(",")]:
            if lang in native_to_locale:
                codes.append(native_to_locale[lang])
        return codes

    def get_rapid(self) -> int | None:
        return self._find_rating("rapid")

    def get_blitz(self) -> int | None:
        return self._find_rating("blitz")

    def get_bullet(self) -> int | None:
        return self._find_rating("bullet")

    def _find_rating(self, name) -> int | None:
        if self.stats_soup is None:
            return None
        a = self.stats_soup.find("a", href=f"/@/{self.username}/perf/{name}")
        if not isinstance(a, Tag):
            return None
        rating = a.find("rating")
        if not isinstance(rating, Tag):
            return None
        strong = rating.find("strong")
        if not isinstance(strong, Tag):
            return None
        value = strong.get_text()
        if value[-1] == "?":
            value = value[:-1]
        try:
            return int(value)
        except ValueError:
            return None


class Pipeline(BasePipeline):
    def get_fetcher(self, session: aiohttp.ClientSession):
        return Fetcher(session)

    def get_extractor(
        self, fetcher: BaseFetcher, detector: LanguageDetector, username: str
    ):
        return Extractor(fetcher, detector, username)