"""
Dependables for defining Routers.
"""

import re
from dataclasses import dataclass
from logging import getLogger
from typing import Iterator, Protocol

from fastapi import HTTPException, status
from webdav3.exceptions import RemoteResourceNotFound

from ..config import Config
from ..dav_common import caldav_list, webdav_list

_logger = getLogger(__name__)


class NameLister(Protocol):
    """
    Can be called to create an iterator containing some names.
    """

    async def __call__(self) -> Iterator[str]:
        ...


_RESPONSE_OK = {
    status.HTTP_200_OK: {
        "description": "Operation successful",
    },
}


@dataclass(frozen=True)
class FileNameLister:
    """
    Can be called to create an iterator containing file names.

    File names listed will be in `remote_path` and will match the RegEx `re`.
    """

    path_name: str
    re: re.Pattern[str]

    @property
    def responses(self) -> dict:
        return {
            **_RESPONSE_OK,
            status.HTTP_404_NOT_FOUND: {
                "description": f"{self.path_name!r} not found",
                "content": None,
            },
        }

    @property
    async def remote_path(self) -> str:
        cfg = await Config.get()

        return str(cfg.dict()[self.path_name])

    async def __call__(self) -> Iterator[str]:
        try:
            file_names = await webdav_list(await self.remote_path)

            return (
                name
                for name in file_names
                if self.re.search(name)
            )

        except RemoteResourceNotFound:
            _logger.error(
                "WebDAV path %s lost!",
                repr(await self.remote_path),
            )
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND)


@dataclass(frozen=True)
class CalendarNameLister:
    """
    Can be called to create an iterator containing calendar names.
    """

    async def __call__(self) -> Iterator[str]:
        return await caldav_list()


@dataclass(frozen=True)
class AggregateNameLister:
    """
    Can be called to create an iterator containing aggregate calendar names.
    """

    async def __call__(self) -> Iterator[str]:
        cfg = await Config.get()

        return iter(cfg.calendar.aggregates.keys())


@dataclass(frozen=True)
class PrefixFinder:
    """
    Can be called to create an iterator containing some names, all starting
    with a given prefix.

    All names will be taken from the list produced by the called `lister`.
    """

    lister: NameLister

    @property
    def responses(self) -> dict:
        return {
            **_RESPONSE_OK,
            status.HTTP_404_NOT_FOUND: {
                "description": "Failure in lister " +
                repr(self.lister.__class__.__name__),
                "content": None,
            },
        }

    async def __call__(self, prefix: str) -> Iterator[str]:
        return (
            file_name
            for file_name in (await self.lister())
            if file_name.lower().startswith(prefix.lower())
        )


@dataclass(frozen=True)
class PrefixUnique:
    """
    Can be called to determine if a given prefix is unique in the list
    produced by the called `finder`.

    On success, produces the unique name with that prefix. Otherwise,
    throws a HTTPException.
    """

    finder: PrefixFinder

    @property
    def responses(self) -> dict:
        return {
            **_RESPONSE_OK,
            status.HTTP_404_NOT_FOUND: {
                "description": "Prefix not found",
                "content": None,
            },
            status.HTTP_409_CONFLICT: {
                "description": "Ambiguous prefix",
                "content": None,
            },
        }

    async def __call__(self, prefix: str) -> str:
        names = await self.finder(prefix)

        try:
            name = next(names)

        except StopIteration:
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND)

        if any(True for _ in names):
            raise HTTPException(status_code=status.HTTP_409_CONFLICT)

        return name