# Thunder/utils/custom_dl.py

import asyncio
from typing import Any, AsyncGenerator, Awaitable, Callable, Dict, Optional

from pyrogram import Client
from pyrogram.errors import FloodWait
from pyrogram.types import Message

from Thunder.server.exceptions import FileNotFound
from Thunder.utils.file_properties import get_media
from Thunder.utils.logger import logger
from Thunder.vars import Var


class ByteStreamer:
    __slots__ = ('client', 'chat_id')

    def __init__(self, client: Client) -> None:
        self.client = client
        self.chat_id = int(Var.BIN_CHANNEL)

    async def get_message(self, message_id: int) -> Message:
        while True:
            try:
                message = await self.client.get_messages(self.chat_id, message_id)
                break
            except FloodWait as e:
                logger.debug(f"FloodWait: get_message, sleep {e.value}s")
                await asyncio.sleep(e.value)
            except Exception as e:
                logger.debug(f"Error fetching message {message_id}: {e}", exc_info=True)
                raise FileNotFound(f"Message {message_id} not found") from e

        if not message or not message.media:
            raise FileNotFound(f"Message {message_id} not found")
        return message

    async def stream_file(
        self,
        media_ref: int | Message,
        offset: int = 0,
        limit: int = 0,
        fallback_message_id: int | None = None,
        on_fallback_message: Optional[Callable[[Message], Awaitable[None]]] = None
    ) -> AsyncGenerator[bytes, None]:
        chunk_offset = offset // (1024 * 1024)
        chunk_limit = 0
        if limit > 0:
            chunk_limit = ((limit + (1024 * 1024) - 1) // (1024 * 1024)) + 1

        refs: list[int | Message] = [media_ref]
        media_id = media_ref if isinstance(media_ref, int) else None
        if isinstance(media_ref, Message):
            media_id = getattr(media_ref, "id", getattr(media_ref, "message_id", None))
        if fallback_message_id is not None and (media_id is None or fallback_message_id != media_id):
            refs.append(fallback_message_id)

        last_error: Exception | None = None
        for ref in refs:
            started_stream = False
            while True:
                try:
                    target = await self.get_message(ref) if isinstance(ref, int) else ref
                    if (
                        on_fallback_message is not None and
                        fallback_message_id is not None and
                        ref == fallback_message_id and
                        isinstance(target, Message)
                    ):
                        await on_fallback_message(target)
                    async for chunk in self.client.stream_media(
                        target, offset=chunk_offset, limit=chunk_limit
                    ):
                        started_stream = True
                        yield chunk
                    return
                except FloodWait as e:
                    logger.debug(f"FloodWait: stream_file, sleep {e.value}s")
                    await asyncio.sleep(e.value)
                except Exception as e:
                    last_error = e
                    logger.debug(f"Error streaming media ref {ref}: {e}", exc_info=True)
                    if started_stream:
                        raise
                    break

        raise FileNotFound(f"Unable to stream file: {last_error}")

    def get_file_info_sync(self, message: Message) -> Dict[str, Any]:
        media = get_media(message)
        if not media:
            return {"message_id": message.id, "error": "No media"}

        media_type = type(media).__name__.lower()
        file_name = getattr(media, 'file_name', None)
        mime_type = getattr(media, 'mime_type', None)

        if not file_name:
            ext_map = {
                "photo": "jpg",
                "audio": "mp3",
                "voice": "ogg",
                "video": "mp4",
                "animation": "mp4",
                "videonote": "mp4",
                "sticker": "webp",
            }
            ext = ext_map.get(media_type, "bin")
            file_name = f"Thunder_{message.id}.{ext}"

        if not mime_type:
            mime_map = {
                "photo": "image/jpeg",
                "voice": "audio/ogg",
                "videonote": "video/mp4",
            }
            mime_type = mime_map.get(media_type)

        return {
            "message_id": message.id,
            "file_size": getattr(media, 'file_size', 0) or 0,
            "file_name": file_name,
            "mime_type": mime_type,
            "unique_id": getattr(media, 'file_unique_id', None),
            "media_type": media_type
        }

    async def get_file_info(self, message_id: int) -> Dict[str, Any]:
        try:
            message = await self.get_message(message_id)
            return self.get_file_info_sync(message)
        except Exception as e:
            logger.debug(f"Error getting file info for {message_id}: {e}", exc_info=True)
            return {"message_id": message_id, "error": str(e)}