# -*- encoding: utf-8 -*-

import tempfile
import urllib.request
from dataclasses import dataclass
from multiprocessing.pool import ThreadPool
from pathlib import Path
from typing import cast

from bs4 import BeautifulSoup
from PIL import Image

from .scans import Chapter, Manga, ScanFetcher

_BASE_URL = "https://lelscan.net"

_REQUEST_HEADERS = {
    "User-Agent": (
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_1) AppleWebKit/537.36 "
        "(KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36"
    )
}


@dataclass(frozen=True)
class LelScansManga(Manga):
    url: str


@dataclass(frozen=True)
class LelScansChapter(Chapter):
    url: str


class LelScansFetcher(ScanFetcher[LelScansManga, LelScansChapter]):
    def _request(self, url: str) -> bytes | str:
        request = urllib.request.Request(url=url, headers=_REQUEST_HEADERS)

        return cast(bytes | str, urllib.request.urlopen(request).read())

    def list_mangas(self) -> list[LelScansManga]:
        soup = BeautifulSoup(self._request(_BASE_URL), "html.parser")
        assert soup.body is not None

        # find the select
        select = soup.body.select("#header-image > h2 > form > select")[1]
        return sorted(
            (
                LelScansManga(name=option.text, url=option.attrs["value"])
                for option in select.select("option")
            ),
            key=lambda m: m.name,
        )

    def list_chapters(self, manga: LelScansManga) -> list[LelScansChapter]:
        soup = BeautifulSoup(self._request(manga.url), "html.parser")
        assert soup.body is not None

        # find the select
        select = soup.body.select("#header-image > h2 > form > select")[0]

        return sorted(
            (
                LelScansChapter(manga, option.text, url=option.attrs["value"])
                for option in select.select("option")
            ),
            key=lambda c: float(c.number),
        )

    def _fetch_chapter(
        self,
        chapter: LelScansChapter,
        folder: Path,
    ) -> list[Path]:
        print("Retrieving scan {}... ".format(chapter.number))
        folder.mkdir(exist_ok=True)

        # retrieve the main page
        soup = BeautifulSoup(self._request(chapter.url), "html.parser")

        # retrieve the pages
        anchors = soup.select("#navigation a")
        pages: list[tuple[int, str]] = []
        for anchor in anchors:
            try:
                # skip non-page chapter
                pages.append((int(anchor.text), anchor.attrs["href"]))
            except ValueError:
                pass
        pages = sorted(pages)

        # Download each page of the scan
        def retrieve_page(page: tuple[int, str]) -> Path | None:
            number, url = page
            print("  Retrieving page {:02}/{:02d}".format(number, len(pages)))
            soup = BeautifulSoup(
                self._request(url),
                "html.parser",
            )

            url = (
                _BASE_URL
                + soup.select("#image > table > tr > td > a > img")[0]
                .attrs["src"]
                .strip()
            )
            data = self._request(url)

            filepath = folder.joinpath(url.split("/")[-1].split("?")[0])
            with open(filepath, "wb") as fp:
                fp.write(data)  # type: ignore

            # Remove alpha channel, if any:
            try:
                Image.open(filepath).convert("RGB").save(filepath)
            except (OSError, KeyError):
                print(
                    "    Failed to convert page {:02}/{:02d}".format(number, len(pages))
                )

            return filepath

        with ThreadPool() as pool:
            return [image for image in pool.map(retrieve_page, pages) if image]

    def fetch_chapter(
        self,
        chapter: LelScansChapter,
        folder: Path | None = None,
        pdf: Path | None = None,
    ):
        if folder is None:
            with tempfile.TemporaryDirectory() as t:
                images = self._fetch_chapter(chapter, Path(t))
        else:
            images = self._fetch_chapter(chapter, folder)

        if pdf is not None:
            self._merge_scan(pdf, images)


if __name__ == "__main__":
    for manga in LelScansFetcher().list_mangas():
        print(manga)