backend/database.py

import os
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.orm import declarative_base

# Use environment variable for production (PostgreSQL on Render)
# Falls back to SQLite for local development
DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///./scamdetect.db")

# Render provides postgres:// but SQLAlchemy needs postgresql://
if DATABASE_URL.startswith("postgres://"):
    DATABASE_URL = DATABASE_URL.replace("postgres://", "postgresql://", 1)

# check_same_thread is needed only for SQLite
connect_args = {}
if "sqlite" in DATABASE_URL:
    connect_args = {"check_same_thread": False}

engine = create_engine(DATABASE_URL, connect_args=connect_args)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()

# Dependency for API endpoints to get the DB session
def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()