import logging

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.ext.asyncio import AsyncSession

from db.session import get_session
from models.requests import ChatRequest
from models.responses import (
    BounceInfo,
    ChatResponse,
    SourceInfo,
    ThreadStateInfo,
    ValidationEventInfo,
)
from services import chat_service
from services.llm_client import LLMUnavailableError

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/chat", tags=["chat"])


@router.post("", response_model=ChatResponse)
async def chat(req: ChatRequest, session: AsyncSession = Depends(get_session)):
    from main import llm_client, router_client, vectorstore_service

    if vectorstore_service is None or llm_client is None or router_client is None:
        raise HTTPException(status_code=503, detail="Service not ready")

    try:
        result = await chat_service.send_message(
            session=session,
            vectorstore=vectorstore_service,
            llm=llm_client,
            router=router_client,
            text=req.text,
            thread_id=req.thread_id,
            top_k=req.top_k,
            temperature=req.temperature,
            max_tokens=req.max_tokens,
        )
    except LookupError as e:
        await session.rollback()
        raise HTTPException(status_code=404, detail=str(e))
    except LLMUnavailableError as e:
        # Внешний LLM недоступен даже после ретрая — откатываем, чтобы не оставлять
        # «тред-призрак» с одной пользовательской репликой и без ответа ассистента.
        await session.rollback()
        logger.warning("LLM unavailable: %s", e)
        raise HTTPException(
            status_code=503,
            detail="Внешняя модель временно недоступна. Попробуйте ещё раз через минуту.",
        )
    except Exception as e:
        await session.rollback()
        logger.exception("Chat failed")
        raise HTTPException(status_code=500, detail=f"Chat error [{type(e).__name__}]: {e}")

    return ChatResponse(
        thread_id=result["thread_id"],
        thread_name=result["thread_name"],
        message_id=result["message_id"],
        intent_code=result["intent_code"],
        intent_name=result["intent_name"],
        router_intent_code=result.get("router_intent_code", ""),
        config_version=result["config_version"],
        router_version=result.get("router_version"),
        answer=result["answer"],
        sources=[SourceInfo(**s) for s in result["sources"]],
        model_used=result["model_used"],
        assembled_prompt=result["assembled_prompt"],
        thread_state=ThreadStateInfo(**result["thread_state"]),
        bounces=[BounceInfo(**b) for b in result.get("bounces", [])],
        validation_events=[ValidationEventInfo(**v) for v in result.get("validation_events", [])],
        parse_error=result.get("parse_error"),
        routing_loop_triggered=result.get("routing_loop_triggered", False),
        resumed_from_suspended=result.get("resumed_from_suspended", False),
        message_meta=result.get("message_meta"),
        escalation_reason=result.get("escalation_reason"),
        operator_summary=result.get("operator_summary"),
        router_assembled_prompt=result.get("router_assembled_prompt", ""),
        rag_subscription=result.get("rag_subscription"),
    )