"""
Database connection and session management
"""
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base
from app.config import settings
import logging

logger = logging.getLogger(__name__)

# Create async engine
engine = create_async_engine(
    settings.database_url,
    echo=False,  # Set to True for SQL query logging
    pool_size=settings.database_pool_size,
    max_overflow=settings.database_max_overflow,
    pool_pre_ping=True,  # Verify connections before using
)

# Create async session factory
AsyncSessionLocal = async_sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False,
    autocommit=False,
    autoflush=False,
)

# Base class for ORM models
Base = declarative_base()


async def get_db() -> AsyncSession:
    """
    Dependency function for FastAPI to get database sessions

    Usage:
        @app.get("/items")
        async def read_items(db: AsyncSession = Depends(get_db)):
            ...
    """
    async with AsyncSessionLocal() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()


async def init_db():
    """Initialize database - create all tables"""
    from app.models.db import (
        CelestialBody,
        Position,
        Resource,
        StaticData,
        NasaCache,
    )

    async with engine.begin() as conn:
        # Create all tables
        await conn.run_sync(Base.metadata.create_all)

    logger.info("Database tables created successfully")


async def close_db():
    """Close database connections"""
    await engine.dispose()
    logger.info("Database connections closed")