"""Database connection and session management."""

from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.pool import NullPool
from src.config import get_settings
from loguru import logger

settings = get_settings()

# Build async URL — handle both postgresql:// and postgresql+asyncpg://
_db_url = settings.database_url
if _db_url.startswith("postgresql://"):
    _db_url = _db_url.replace("postgresql://", "postgresql+asyncpg://", 1)

# Neon (and most managed Postgres) requires SSL.
# server_settings sets statement_timeout at connection level (Supabase free tier defaults to ~8s,
# which causes ALTER TABLE / CREATE TABLE to randomly fail on startup migrations).
_connect_args = {
    "server_settings": {"statement_timeout": "60000"},  # 60s per statement
}
if "neon.tech" in _db_url or "sslmode=require" in _db_url or "supabase.com" in _db_url:
    _connect_args["ssl"] = "require"
    _db_url = _db_url.split("?")[0]  # asyncpg doesn't accept ?sslmode= in the URL

# Create async engine
engine = create_async_engine(
    _db_url,
    echo=settings.database_echo,
    poolclass=NullPool,
    connect_args=_connect_args,
)

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


async def get_db():
    """Dependency for FastAPI to get DB session."""
    async with AsyncSessionLocal() as session:
        try:
            yield session
        except Exception as e:
            logger.error(f"Database session error: {e}")
            await session.rollback()
            raise
        finally:
            await session.close()


async def init_db():
    """Initialize database (create tables)."""
    from src.models.database import Base
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
        logger.info("Database tables initialized")


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