"""
Database configuration and session management.
"""

from collections.abc import AsyncGenerator

from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base
from app.core.config import settings

# Create async engine
# prepared_statement_cache_size=0 disables SQLAlchemy's asyncpg prepared-statement
# LRU cache. This prevents ProgrammingError("cached statement plan is invalid") when
# CREATE TYPE / CREATE TABLE DDL (run via create_all at startup) invalidates previously
# cached statement plans on the same connection.
engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    pool_size=settings.DATABASE_POOL_SIZE,
    max_overflow=settings.DATABASE_MAX_OVERFLOW,
    pool_pre_ping=True,
    connect_args={"prepared_statement_cache_size": 0},
)

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

# Base class for models
Base = declarative_base()


async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """Dependency for getting async database session"""
    async with async_session_maker() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()