import asyncio
import json
import os
import os.path
from typing import List, Union

import aiohttp
from bs4 import BeautifulSoup

from app.exporter import BaseExporter
from app.repo import AnsiColor, Site
from app.scraper import BaseScraper

# The number of coach listing pages we will at most iterate through. This number
# was determined by going to chess.com/coaches?sortBy=alphabetical&page=1 and
# traversing to the last page.
MAX_PAGES = 64

# How long to wait between a batch of network requests.
SLEEP_SECS = 3


class Scraper(BaseScraper):
    def __init__(self, session: aiohttp.ClientSession):
        super().__init__(site=Site.CHESSCOM.value, session=session)

    async def download_usernames(self) -> List[str]:
        """Scan through chess.com/coaches for all coaches' usernames.

        @return
            The complete list of scraped usernames across every coach listing
            page.
        """
        usernames = []
        for page_no in range(1, MAX_PAGES + 1):
            filepath = self.path_page_file(page_no)
            try:
                with open(filepath, "r") as f:
                    self.log(
                        [
                            (AnsiColor.INFO, "[INFO]"),
                            (None, ": Reading file "),
                            (AnsiColor.DATA, filepath),
                        ]
                    )
                    usernames.extend([line.strip() for line in f.readlines()])
            except FileNotFoundError:
                page_usernames = await self._scrape_page(page_no)
                if not page_usernames:
                    self.log(
                        [
                            (AnsiColor.ERROR, "[ERROR]"),
                            (None, ": Could not scrape page "),
                            (AnsiColor.DATA, str(page_no)),
                        ]
                    )
                    continue
                with open(filepath, "w") as f:
                    for username in page_usernames:
                        f.write(f"{username}\n")
                usernames.extend(page_usernames)
                self.log(
                    [
                        (AnsiColor.INFO, "[INFO]"),
                        (None, ": Downloaded page "),
                        (AnsiColor.DATA, filepath),
                    ]
                )
                await asyncio.sleep(SLEEP_SECS)

        return usernames

    async def _scrape_page(self, page_no: int) -> List[str]:
        """Scan through chess.com/coaches/?page=<n> for all coaches' usernames.

        @param page_no
            The page consisting of at most 25 coaches (at the time of writing)
            whose usernames are to be scraped.
        @return
            The list of scraped usernames on the specified coach listing page.
        """
        url = f"https://www.chess.com/coaches?sortBy=alphabetical&page={page_no}"
        response, status_code = await self.request(url)
        if response is None:
            self.log(
                [
                    (AnsiColor.ERROR, "[ERROR]"),
                    (None, ": Received status "),
                    (AnsiColor.DATA, f"{status_code} "),
                    (None, "when downloading page "),
                    (AnsiColor.DATA, str(page_no)),
                ]
            )
            return

        usernames = []
        soup = BeautifulSoup(response, "lxml")
        members = soup.find_all("a", class_="members-categories-username")
        for member in members:
            href = member.get("href")
            username = href[len("https://www.chess.com/member/") :]
            usernames.append(username)

        return usernames

    async def download_profile(self, username: str):
        """For each coach, download coach-specific data.

        This sends three parallel requests for:
        * the coach's profile,
        * the coach's recent activity,
        * the coach's stats.

        @param username
            The coach username corresponding to the downloaded files.
        """
        used_network = await asyncio.gather(
            self._download_profile_file(
                url=f"https://www.chess.com/member/{username}",
                username=username,
                filename=self.path_coach_file(username, f"{username}.html"),
            ),
            self._download_profile_file(
                url=f"https://www.chess.com/callback/member/activity/{username}?page=1",
                username=username,
                filename=self.path_coach_file(username, "activity.json"),
            ),
            self._download_profile_file(
                url=f"https://www.chess.com/callback/member/stats/{username}",
                username=username,
                filename=self.path_coach_file(username, "stats.json"),
            ),
        )
        if any(used_network):
            self.log(
                [
                    (AnsiColor.INFO, "[INFO]"),
                    (None, ": Downloaded data for coach "),
                    (AnsiColor.DATA, username),
                ]
            )
            await asyncio.sleep(SLEEP_SECS)
        else:
            self.log(
                [
                    (AnsiColor.INFO, "[INFO]"),
                    (None, ": Skipping download for coach "),
                    (AnsiColor.DATA, username),
                ]
            )

    async def _download_profile_file(self, url: str, username: str, filename: str):
        """Writes the contents of url into the specified file.

        @param url
            The URL of the file to download.
        @param username
            The coach username corresponding to the downloaded file.
        @param filename
            The output file to write the downloaded content to.
        @return:
            True if we make a network request. False otherwise.
        """
        if os.path.isfile(filename):
            return False

        response, _unused_status = await self.request(url)
        if response is not None:
            with open(filename, "w") as f:
                f.write(response)

        return True


class Exporter(BaseExporter):
    def __init__(self, username: str):
        super().__init__(site=Site.CHESSCOM.value, username=username)

        self.stats_json = {}
        try:
            with open(self.path_coach_file(username, "stats.json"), "r") as f:
                for s in json.load(f).get("stats", []):
                    if "key" in s and "stats" in s:
                        self.stats_json[s["key"]] = s["stats"]
        except FileNotFoundError:
            pass

    def export_rapid(self) -> Union[int, None]:
        return self.stats_json.get("rapid", {}).get("rating")

    def export_blitz(self) -> Union[int, None]:
        return self.stats_json.get("lightning", {}).get("rating")

    def export_bullet(self) -> Union[int, None]:
        return self.stats_json.get("bullet", {}).get("rating")