import logging

from fastapi import APIRouter, HTTPException

from api.deps import get_ai_service, get_orm, get_retrieval_service
from api.schemas import (
    AnswerRequest,
    AnswerResponse,
    ClassificationResult,
    RetrievedChunk,
    SearchRequest,
    SearchResponse,
)
from api.services.legal_ai import build_fallback_title, infer_law_types


router = APIRouter(prefix="/api/v1/rag", tags=["rag"])
logger = logging.getLogger(__name__)


@router.post("/search", response_model=SearchResponse)
async def search(payload: SearchRequest) -> SearchResponse:
    logger.info(
        "RAG search request: category=%s region=%s top_k=%s question_length=%s",
        payload.category,
        payload.region,
        payload.top_k,
        len(payload.question),
    )
    ai_service = get_ai_service()
    retrieval = get_retrieval_service()

    try:
        classification = await ai_service.classify(
            question=payload.question,
            category=payload.category,
            region=payload.region,
            user_type=payload.user_type,
            history=payload.history,
        )
        chunks = await retrieval.retrieve(
            classification=classification,
            fallback_law_types=payload.law_types or infer_law_types(payload.category),
            top_k=payload.top_k,
        )
    except RuntimeError as exc:
        logger.exception("RAG search failed")
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    return SearchResponse(
        classification=classification,
        generated_queries=classification.search_queries,
        retrieved_chunks=[RetrievedChunk(**chunk) for chunk in chunks],
    )


@router.post("/answer", response_model=AnswerResponse)
async def answer(payload: AnswerRequest) -> AnswerResponse:
    logger.info(
        "RAG answer request: user_id=%s consultation_id=%s save_history=%s category=%s region=%s top_k=%s question_length=%s",
        payload.user_id,
        payload.consultation_id,
        payload.save_history,
        payload.category,
        payload.region,
        payload.top_k,
        len(payload.question),
    )
    ai_service = get_ai_service()
    retrieval = get_retrieval_service()
    orm = get_orm()

    try:
        classification = await ai_service.classify(
            question=payload.question,
            category=payload.category,
            region=payload.region,
            user_type=payload.user_type,
            history=payload.history,
        )
        chunks = await retrieval.retrieve(
            classification=classification,
            fallback_law_types=payload.law_types or infer_law_types(payload.category),
            top_k=payload.top_k,
        )
    except RuntimeError as exc:
        logger.exception("RAG answer failed on classification/retrieval stage")
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    if not chunks:
        logger.warning("RAG answer request returned no reliable chunks")
        raise HTTPException(
            status_code=404,
            detail="No reliable law chunks were found for this question.",
        )

    try:
        answer_text = await ai_service.answer(
            question=payload.question,
            category=payload.category,
            region=payload.region,
            user_type=payload.user_type,
            history=payload.history,
            sources=chunks,
        )
    except RuntimeError as exc:
        logger.exception("RAG answer failed on generation stage")
        raise HTTPException(status_code=502, detail=str(exc)) from exc

    consultation_id = payload.consultation_id
    user_message_id = None
    assistant_message_id = None

    if payload.save_history:
        if payload.user_id is None:
            raise HTTPException(
                status_code=400,
                detail="user_id is required when save_history=true",
            )
        user = await orm.get_user(payload.user_id)
        if user is None:
            raise HTTPException(
                status_code=404,
                detail="User was not found. Start the bot first so the profile is created.",
            )

        if consultation_id is not None:
            consultation = await orm.get_consultation(
                consultation_id=consultation_id,
                user_id=payload.user_id,
            )
            if consultation is None:
                raise HTTPException(
                    status_code=404,
                    detail="Consultation was not found for this user.",
                )

        if consultation_id is None:
            try:
                consultation_title = await ai_service.generate_consultation_title(
                    question=payload.question,
                    category=payload.category or classification.legal_domain,
                    answer=answer_text,
                )
            except RuntimeError:
                logger.exception("Consultation title generation failed, using fallback title")
                consultation_title = build_fallback_title(payload.question)

            consultation = await orm.create_consultation(
                user_id=payload.user_id,
                category=payload.category or classification.legal_domain,
                title=consultation_title,
                region=payload.region or classification.region,
            )
            consultation_id = consultation.id

        user_message = await orm.create_message(
            consultation_id=consultation_id,
            role="user",
            content=payload.question,
        )
        user_message_id = user_message.id

        await orm.create_rag_query(
            consultation_id=consultation_id,
            user_message_id=user_message_id,
            generated_queries=classification.search_queries,
            retrieved_chunks=chunks,
        )

        assistant_message = await orm.create_message(
            consultation_id=consultation_id,
            role="assistant",
            content=answer_text,
            sources_json=chunks,
        )
        assistant_message_id = assistant_message.id

    return AnswerResponse(
        classification=classification,
        generated_queries=classification.search_queries,
        retrieved_chunks=[RetrievedChunk(**chunk) for chunk in chunks],
        answer=answer_text,
        consultation_id=consultation_id,
        user_message_id=user_message_id,
        assistant_message_id=assistant_message_id,
    )