# backend/db/session.py

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from sqlalchemy.pool import NullPool
from sqlalchemy.orm import Session
from dotenv import load_dotenv
import os

# Load environment variables
load_dotenv()

# Read .env settings
USER = os.getenv("user")
PASSWORD = os.getenv("password")
HOST = os.getenv("host")
PORT = os.getenv("port")
DBNAME = os.getenv("dbname")

# Supabase Transaction Pooler (IPv4-safe) URI
DATABASE_URL = f"postgresql+psycopg2://{USER}:{PASSWORD}@{HOST}:{PORT}/{DBNAME}?sslmode=require"

# SQLAlchemy engine with NullPool for Supabase
engine = create_engine(DATABASE_URL, poolclass=NullPool)

# Session factory (used for queries)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# Base class for ORM models
Base = declarative_base()

# ───────────────────────────────
# FastAPI helper (NEW, non-breaking)
# ───────────────────────────────

def get_db() -> Session:
    """
    Yield a DB session for FastAPI dependencies.
    Closes the session automatically after the request.
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()