"""
Database setup and session management.
Uses SQLAlchemy with SQLite for local dev, Postgres-compatible schema.
"""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Session
from pathlib import Path
import logging

from app.config import settings

logger = logging.getLogger(__name__)

# Database path
DB_DIR = settings.DATA_DIR / "billing"
DB_DIR.mkdir(parents=True, exist_ok=True)
DATABASE_URL = f"sqlite:///{DB_DIR / 'billing.db'}"

# Create engine
engine = create_engine(
    DATABASE_URL,
    connect_args={"check_same_thread": False},  # SQLite specific
    echo=False  # Set to True for SQL query logging
)

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

# Base class for models
Base = declarative_base()


def get_db() -> Session:
    """Get database session (dependency for FastAPI)."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    """Initialize database tables."""
    Base.metadata.create_all(bind=engine)
    logger.info("Database tables created/verified")


def drop_db():
    """Drop all tables (use with caution!)."""
    Base.metadata.drop_all(bind=engine)
    logger.warning("All database tables dropped")