import logging

from telethon import TelegramClient
from telethon.tl.functions.channels import GetFullChannelRequest

from bot.models import ChannelMessage

log = logging.getLogger(__name__)


async def fetch_channel_messages(
    client: TelegramClient,
    channel: str,
    limit: int | None = None,
) -> tuple[list[ChannelMessage], dict]:
    """Fetch messages and basic stats from a public channel."""
    entity = await client.get_entity(channel)
    full = await client(GetFullChannelRequest(entity))

    stats = {
        "title": entity.title,
        "username": getattr(entity, "username", None),
        "subscribers": full.full_chat.participants_count,
    }

    messages: list[ChannelMessage] = []
    async for msg in client.iter_messages(entity, limit=limit):
        if not msg.text:
            continue
        messages.append(
            ChannelMessage(
                id=msg.id,
                date=msg.date,
                text=msg.text,
                views=msg.views,
                forwards=msg.forwards,
                replies=msg.replies.replies if msg.replies else None,
            )
        )

    messages.reverse()
    log.info("Fetched %d text messages from %s", len(messages), channel)
    return messages, stats