from fastapi import APIRouter, Depends, HTTPException, status
from bson import ObjectId
from datetime import datetime, timezone
from typing import List

from app.database import get_db
from app.dependencies import get_current_user
from app.models.question import QuestionSetIn, QuestionSetOut, QuestionItem
from app.services.gemini_service import generate_interview_questions

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

@router.post("/generate", response_model=QuestionSetOut, status_code=status.HTTP_201_CREATED)
async def generate_questions(
    req: QuestionSetIn,
    db=Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    try:
        resume_oid = ObjectId(req.resume_id)
        req_oid = ObjectId(req.requirement_id)
    except:
        raise HTTPException(status_code=400, detail="Invalid ID format")

    # Fetch resume
    resume = await db["resumes"].find_one({"_id": resume_oid, "uploaded_by": current_user["google_id"]})
    if not resume:
        raise HTTPException(status_code=404, detail="Resume not found")

    # Fetch requirements
    requirement = await db["requirements"].find_one({"_id": req_oid, "user_id": current_user["google_id"]})
    if not requirement:
        raise HTTPException(status_code=404, detail="Requirement not found")

    # Generate questions via Gemini
    try:
        # Pass resume text and requirements to Gemini
        generated_data = await generate_interview_questions(
            resume_text=resume.get("parsed", {}).get("raw_text", ""),
            role_name=requirement.get("role_name", ""),
            skills=requirement.get("mandatory_skills", []) + requirement.get("nice_to_have_skills", []),
            experience=requirement.get("experience_years", 0),
            projects=resume.get("parsed", {}).get("projects", [])
        )
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

    # Save to MongoDB
    now = datetime.now(timezone.utc)
    doc = {
        "user_id": current_user["google_id"],
        "resume_id": req.resume_id,
        "requirement_id": req.requirement_id,
        "questions": generated_data,
        "created_at": now
    }
    
    # Upsert logic to overwrite if same pair exists
    result = await db["questions"].find_one_and_update(
        {
            "user_id": current_user["google_id"],
            "resume_id": req.resume_id,
            "requirement_id": req.requirement_id
        },
        {"$set": doc},
        upsert=True,
        return_document=True
    )
    
    result["id"] = str(result.pop("_id"))
    return result

@router.get("/{resume_id}", response_model=List[QuestionSetOut])
async def get_questions_for_resume(
    resume_id: str,
    db=Depends(get_db),
    current_user: dict = Depends(get_current_user),
):
    cursor = db["questions"].find({"user_id": current_user["google_id"], "resume_id": resume_id}).sort("created_at", -1)
    results = []
    async for doc in cursor:
        doc["id"] = str(doc.pop("_id"))
        results.append(doc)
    return results