app/routes/translate.py

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from sqlalchemy.exc import IntegrityError
from app.database import get_db
from app.models.translation import Translation
from app.schemas.translate import TranslateRequest, TranslateResponse
from app.services.openai_service import OpenAIService
import logging

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


@router.post("/translate/urdu", response_model=TranslateResponse)
async def translate_to_urdu(
    request: TranslateRequest,
    db: Session = Depends(get_db)
):
    """
    Translate English text to Urdu.

    - Checks cache first for existing translation
    - If not cached, calls Gemini for translation
    - Stores new translations in database for future requests
    """
    # T007: Check cache first
    cached = db.query(Translation).filter_by(cache_key=request.cache_key).first()
    if cached:
        return TranslateResponse(urdu_text=cached.urdu_text, cached=True)

    # Perform translation via OpenAI SDK + Gemini
    try:
        openai_service = OpenAIService()
        urdu_text = await openai_service.translate_to_urdu(request.content)
    except Exception as e:
        logger.error(f"Gemini translation error: {e}")
        raise HTTPException(status_code=503, detail="Translation service temporarily unavailable")

    # T008 & T009: Store in cache with race condition handling
    try:
        translation = Translation(
            cache_key=request.cache_key,
            english_text=request.content,
            urdu_text=urdu_text
        )
        db.add(translation)
        db.commit()
    except IntegrityError:
        db.rollback()
        # Race condition - another request cached this key
        cached = db.query(Translation).filter_by(cache_key=request.cache_key).first()
        if cached:
            return TranslateResponse(urdu_text=cached.urdu_text, cached=True)
    except Exception as e:
        logger.error(f"Database error: {e}")
        # Return translation even if caching fails
        return TranslateResponse(urdu_text=urdu_text, cached=False)

    return TranslateResponse(urdu_text=urdu_text, cached=False)