from sqlalchemy import event
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
from sqlalchemy.orm import DeclarativeBase

from app.config import settings

engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    connect_args={"check_same_thread": False},
)

# Enable WAL mode for concurrent read/write performance
@event.listens_for(engine.sync_engine, "connect")
def _set_sqlite_pragma(dbapi_conn, connection_record):
    cursor = dbapi_conn.cursor()
    cursor.execute("PRAGMA journal_mode=WAL")
    cursor.execute("PRAGMA synchronous=NORMAL")
    cursor.execute("PRAGMA cache_size=-64000")  # 64MB cache
    cursor.execute("PRAGMA busy_timeout=5000")  # 5s wait on lock
    cursor.execute("PRAGMA foreign_keys=ON")
    cursor.close()

async_session = async_sessionmaker(
    bind=engine,
    class_=AsyncSession,
    expire_on_commit=False,
)


class Base(DeclarativeBase):
    pass


async def get_db() -> AsyncSession:
    """Dependency injection for async database sessions."""
    async with async_session() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()


async def init_db() -> None:
    """Create all database tables."""
    async with engine.begin() as conn:
        from app.models import (  # noqa: F401
            AlarmRecord,
            AttendanceRecord,
            AuditLog,
            BluetoothRecord,
            CommandLog,
            Device,
            HeartbeatRecord,
            LocationRecord,
        )

        await conn.run_sync(Base.metadata.create_all)