from fastapi import APIRouter, Depends
from sqlalchemy.orm import Session

from app.db.session import get_db
from app.schemas.chat import ChatRequest, ChatResponse
from app.schemas.retrieval import RetrievalRequest
from app.services.retrieval import retrieve

router = APIRouter(tags=["chat"])


@router.post("/chat", response_model=ChatResponse)
def chat(payload: ChatRequest, db: Session = Depends(get_db)) -> ChatResponse:
    """运行可复核的关键词检索；模型未配置时绝不伪造生成式回答。"""
    result = retrieve(db, RetrievalRequest(query=payload.question, top_k=5))
    if result.status == "no_evidence":
        return ChatResponse(
            answer="未检索到可用的已核验知识依据。请补充更具体的关键词，或由管理员补充并审核资料。",
            status="no_evidence",
            sources=[],
            retrieval_run_id=result.run_id,
        )
    return ChatResponse(
        answer=(
            f"已检索到 {result.total_hits} 条已核验知识依据。当前尚未配置大语言模型，"
            "因此系统仅返回可追溯证据，不生成或改写答案。"
        ),
        status="retrieval_only",
        sources=[
            {"title": hit.title, "source_url": hit.source_url}
            for hit in result.results
        ],
        retrieval_run_id=result.run_id,
    )