import uuid

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

from app.auth.deps import get_current_user
from app.database import get_db
from app.models.collection import Collection
from app.models.search_schemas import SearchRequest, SearchResponse, SourceItem
from app.models.user import User
from app.services.embedding import embed_query
from app.services.vector_store import search as qdrant_search
from app.services.reranking import rerank
from app.services.llm import generate_answer

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

FETCH_K = 20
FINAL_K = 5


@router.post("/search", response_model=SearchResponse)
async def search(
    body: SearchRequest,
    user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(Collection).where(
            Collection.id == uuid.UUID(body.collection_id),
            Collection.user_id == user.id,
        )
    )
    collection = result.scalar_one_or_none()
    if not collection:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Collection not found")

    query_vector = await embed_query(body.query)

    qdrant_results = await qdrant_search(
        tenant_id=str(user.id),
        query_vector=query_vector,
        collection_id=body.collection_id,
        k=FETCH_K,
    )

    if not qdrant_results:
        return SearchResponse(
            answer="Недостаточно информации в истории обращений" if body.generate_answer else None,
            sources=[],
        )

    reranked = rerank(body.query, qdrant_results, k=FINAL_K)

    sources = [
        SourceItem(ticket_id=r["ticket_id"], score=r["score"], category=r["category"])
        for r in reranked
    ]

    answer = None
    if body.generate_answer:
        context = "\n\n".join(
            f"Тикет №{r['ticket_id']} ({r['category']}):\n{r['full_text']}"
            for r in reranked
        )
        answer = await generate_answer(body.query, context)

    return SearchResponse(answer=answer, sources=sources)