import re
from dataclasses import dataclass
from datetime import date
from io import BytesIO
from typing import cast

from fastapi import Depends
from PIL import Image, ImageFont

from .advent_image import _XY, AdventImage
from .calendar_config import CalendarConfig, get_calendar_config
from .config import Config, get_config
from .dav.webdav import WebDAV
from .helpers import (
    RE_TTF,
    EventDates,
    Random,
    list_fonts,
    list_images_auto,
    list_images_manual,
    load_image,
    set_len,
)


async def get_all_sorted_days(
    cal_cfg: CalendarConfig = Depends(get_calendar_config),
) -> list[int]:
    """
    Alle Tage, für die es ein Türchen gibt
    """

    return sorted(set(door.day for door in cal_cfg.doors))


async def get_all_parts(
    cfg: Config = Depends(get_config),
    days: list[int] = Depends(get_all_sorted_days),
) -> dict[int, str]:
    """
    Lösung auf vorhandene Tage aufteilen
    """

    # noch keine Buchstaben verteilt
    result = {day: "" for day in days}
    # extra-Tage ausfiltern
    days = [day for day in days if day not in cfg.puzzle.extra_days]

    solution_length = len(cfg.solution.clean)
    num_days = len(days)

    rnd = await Random.get()
    solution_days = [
        # wie oft passen die Tage "ganz" in die Länge der Lösung?
        # zB 26 Buchstaben // 10 Tage == 2 mal => 2 Zeichen pro Tag
        *rnd.shuffled(days * (solution_length // num_days)),
        # wie viele Buchstaben bleiben übrig?
        # zB 26 % 10 == 6 Buchstaben => an 6 Tagen ein Zeichen mehr
        *rnd.sample(days, solution_length % num_days),
    ]

    for day, letter in zip(solution_days, cfg.solution.clean):
        result[day] += letter

    return result


async def get_all_event_dates(
    cfg: Config = Depends(get_config),
    days: list[int] = Depends(get_all_sorted_days),
    parts: dict[int, str] = Depends(get_all_parts),
) -> EventDates:
    """
    Aktueller Kalender-Zeitraum
    """

    if cfg.puzzle.skip_empty:
        days = [day for day in days if parts[day] != "" or day in cfg.puzzle.extra_days]

    return EventDates(
        today=date.today(),
        begin_month=cfg.puzzle.begin_month,
        begin_day=cfg.puzzle.begin_day,
        events=days,
        close_after=cfg.puzzle.close_after,
    )


async def get_all_auto_image_names(
    days: list[int] = Depends(get_all_sorted_days),
    images: list[str] = Depends(list_images_auto),
) -> dict[int, str]:
    """
    Bilder: Reihenfolge zufällig bestimmen
    """

    rnd = await Random.get()
    ls = set_len(images, len(days))

    return dict(zip(days, rnd.shuffled(ls)))


async def get_all_manual_image_names(
    manual_image_names: list[str] = Depends(list_images_manual),
) -> dict[int, str]:
    """
    Bilder: "manual" zuordnen
    """

    num_re = re.compile(r"/(\d+)\.", flags=re.IGNORECASE)
    return {
        int(num_match.group(1)): name
        for name in manual_image_names
        if (num_match := num_re.search(name)) is not None
    }


async def get_all_image_names(
    auto_image_names: dict[int, str] = Depends(get_all_auto_image_names),
    manual_image_names: dict[int, str] = Depends(get_all_manual_image_names),
) -> dict[int, str]:
    """
    Bilder "auto" und "manual" zu Tagen zuordnen
    """

    result = auto_image_names.copy()
    result.update(manual_image_names)

    return result


@dataclass(slots=True, frozen=True)
class TTFont:
    # Dateiname
    file_name: str

    # Schriftgröße für den Font
    size: int = 50

    @property
    async def font(self) -> "ImageFont._Font":
        return ImageFont.truetype(
            font=BytesIO(await WebDAV.read_bytes(self.file_name)),
            size=100,
        )


async def get_all_ttfonts(
    font_names: list[str] = Depends(list_fonts),
) -> list[TTFont]:
    result = []

    for name in font_names:
        assert (size_match := RE_TTF.search(name)) is not None

        result.append(
            TTFont(
                file_name=name,
                size=int(size_match.group(1)),
            )
        )

    return result


async def gen_day_auto_image(
    day: int,
    cfg: Config,
    auto_image_names: dict[int, str],
    day_parts: dict[int, str],
    ttfonts: list[TTFont],
) -> Image.Image:
    """
    Automatisch generiertes Bild erstellen
    """

    # Datei existiert garantiert!
    img = await load_image(auto_image_names[day])
    image = await AdventImage.from_img(img, cfg)

    rnd = await Random.get(day)
    xy_range = range(cfg.image.border, (cfg.image.size - cfg.image.border))

    # Buchstaben verstecken
    for letter in day_parts[day]:
        await image.hide_text(
            xy=cast(_XY, tuple(rnd.choices(xy_range, k=2))),
            text=letter,
            font=await rnd.choice(ttfonts).font,
        )

    return image.img


async def get_day_image(
    day: int,
    days: list[int] = Depends(get_all_sorted_days),
    cfg: Config = Depends(get_config),
    manual_image_names: dict[int, str] = Depends(get_all_manual_image_names),
    auto_image_names: dict[int, str] = Depends(get_all_auto_image_names),
    day_parts: dict[int, str] = Depends(get_all_parts),
    ttfonts: list[TTFont] = Depends(get_all_ttfonts),
) -> Image.Image | None:
    """
    Bild für einen Tag abrufen
    """

    if day not in days:
        return None

    try:
        # Versuche "manual"-Bild zu laden
        img = await load_image(manual_image_names[day])

        # Als AdventImage verarbeiten
        image = await AdventImage.from_img(img, cfg)
        return image.img

    except (KeyError, RuntimeError):
        # Erstelle automatisch generiertes Bild
        return await gen_day_auto_image(
            day=day,
            cfg=cfg,
            auto_image_names=auto_image_names,
            day_parts=day_parts,
            ttfonts=ttfonts,
        )