"""
Database connection and session management.
"""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

from app.config import settings

# Create synchronous engine
engine = create_engine(
    settings.database_url,
    pool_pre_ping=True,
    pool_size=10,
    max_overflow=20,
    echo=settings.debug
)

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

# Base class for models
Base = declarative_base()


def get_db():
    """
    Dependency that provides a database session.
    Ensures session is closed after request.
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    """Initialize database tables."""
    from app.models import (
        user, establishment, room, client,
        reservation, folio, payment, department, stats
    )
    Base.metadata.create_all(bind=engine)