import logging
from typing import TYPE_CHECKING

from src import domain, dto

if TYPE_CHECKING:
    from .. import Usecase

log = logging.getLogger(__name__)


async def get_external_channels(self: 'Usecase', input: dto.GetExternalChannelsInput) -> dto.GetExternalChannelsOutput:
    target_channel = await self.database.get_target_channel(input.user_id, channel_id=input.target_channel_id)
    if not target_channel:
        log.warning('Target channel %s not found or not accessible for user %s', input.target_channel_id, input.user_id)
        raise domain.TargetChannelNotFound(input.target_channel_id)

    channels = await self.database.get_external_channels_for_target(input.target_channel_id)

    return dto.GetExternalChannelsOutput(
        external_channels=[
            dto.ExternalChannelOutput(
                id=channel.id,
                telegram_id=channel.telegram_id,
                title=channel.title,
                username=channel.username,
                description=channel.description,
                subscribers_count=channel.subscribers_count,
            )
            for channel in channels
        ]
    )