from __future__ import annotations

import json
from collections.abc import AsyncGenerator

from sqlalchemy import select

from yuxi.channel.domain.model.message.stream_chat_request import StreamChatRequest
from yuxi.repositories.agent_config_repository import AgentConfigRepository
from yuxi.storage.postgres.models_business import User
from yuxi.utils.logging_config import logger

_CHANNEL_SERVICE_ROLE = "channel_service"


class AgentAdapter:
    def __init__(self, session_factory):
        self._session_factory = session_factory

    async def _get_service_user(self, db):
        stmt = select(User).where(User.role == _CHANNEL_SERVICE_ROLE).limit(1)
        result = await db.execute(stmt)
        user = result.scalar_one_or_none()
        if user:
            return user
        stmt = select(User).where(User.role == "superadmin").limit(1)
        result = await db.execute(stmt)
        fallback = result.scalar_one_or_none()
        if fallback:
            logger.warning(
                "no %s user found, falling back to superadmin; create a %s user for production",
                _CHANNEL_SERVICE_ROLE,
                _CHANNEL_SERVICE_ROLE,
            )
        return fallback

    async def stream_chat(self, request: StreamChatRequest) -> str:
        chunks = []
        async for chunk in self.stream_chat_iter(request):
            chunks.append(chunk)
        return "".join(chunks)

    async def stream_chat_iter(self, request: StreamChatRequest) -> AsyncGenerator[str, None]:
        from yuxi.services.chat_service import stream_agent_chat

        async with self._session_factory() as db:
            service_user = await self._get_service_user(db)

            if not service_user:
                logger.error("no service user found for channel agent request")
                yield "Error: no service user found"
                return

            accumulated: list[str] = []

            async for raw_chunk in stream_agent_chat(
                query=request.content,
                agent_config_id=request.agent_config_id,
                thread_id=request.session_id,
                meta={"request_id": request.message_id},
                image_content=None,
                current_user=service_user,
                db=db,
            ):
                try:
                    data = json.loads(raw_chunk)
                    content = data.get("response")
                    if content:
                        accumulated.append(content)
                        yield content
                    status = data.get("status")
                    if status == "error":
                        error_msg = data.get("error_message", "unknown error")
                        logger.error("stream_agent_chat error: %s", error_msg)
                        if not accumulated:
                            yield f"Error: {error_msg}"
                        return
                except (json.JSONDecodeError, AttributeError):
                    pass

    async def resolve_agent_id(self, agent_config_id: int) -> str:
        async with self._session_factory() as session:
            repo = AgentConfigRepository(session)
            config = await repo.get_by_id(config_id=agent_config_id)
            return config.agent_id if config else "chatbot"