from typing import Union, AsyncGenerator, Optional

import pyrogram
from pyrogram import types, raw, utils


class GetChatPhotos:
    async def get_chat_photos(
        self: "pyrogram.Client",
        chat_id: Union[int, str],
        limit: int = 0,
    ) -> Optional[AsyncGenerator["types.Photo", None]]:
        peer_id = await self.resolve_peer(chat_id)

        if isinstance(peer_id, raw.types.InputPeerChannel):
            r = await self.invoke(
                raw.functions.channels.GetFullChannel(channel=peer_id)
            )

            current = types.Photo._parse(self, r.full_chat.chat_photo) or []

            r = await utils.parse_messages(
                self,
                await self.invoke(
                    raw.functions.messages.Search(
                        peer=peer_id,
                        q="",
                        filter=raw.types.InputMessagesFilterChatPhotos(),
                        min_date=0,
                        max_date=0,
                        offset_id=0,
                        add_offset=0,
                        limit=limit,
                        max_id=0,
                        min_id=0,
                        hash=0,
                    )
                ),
            )

            extra = [message.new_chat_photo for message in r]

            if extra:
                if current:
                    photos = (
                        ([current] + extra)
                        if current.file_id != extra[0].file_id
                        else extra
                    )
                else:
                    photos = extra
            else:
                if current:
                    photos = [current]
                else:
                    photos = []

            current = 0

            for photo in photos:
                yield photo

                current += 1

                if current >= limit:
                    return
        else:
            current = 0
            total = limit or (1 << 31)
            limit = min(100, total)
            offset = 0

            while True:
                r = await self.invoke(
                    raw.functions.photos.GetUserPhotos(
                        user_id=peer_id, offset=offset, max_id=0, limit=limit
                    )
                )

                photos = [types.Photo._parse(self, photo) for photo in r.photos]

                if not photos:
                    return

                offset += len(photos)

                for photo in photos:
                    yield photo

                    current += 1

                    if current >= total:
                        return
