# ================================================================
# services/forecasting/app/core/database.py
# ================================================================
"""
Database configuration for forecasting service
"""

import structlog
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy import text
from typing import AsyncGenerator

from app.core.config import settings
from shared.database.base import Base, DatabaseManager

logger = structlog.get_logger()

# Create async engine
async_engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    pool_size=10,
    max_overflow=20,
    pool_pre_ping=True,
    pool_recycle=3600
)

# Create async session factory
AsyncSessionLocal = async_sessionmaker(
    bind=async_engine,
    class_=AsyncSession,
    expire_on_commit=False
)

async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """Get database session"""
    async with AsyncSessionLocal() as session:
        try:
            yield session
        except Exception as e:
            await session.rollback()
            logger.error("Database session error", error=str(e))
            raise
        finally:
            await session.close()

async def init_database():
    """Initialize database tables"""
    try:
        async with async_engine.begin() as conn:
            # Import all models to ensure they are registered
            from app.models.forecast import ForecastBatch, Forecast
            from app.models.prediction import PredictionBatch, Prediction

            # Create all tables
            await conn.run_sync(Base.metadata.create_all)

        logger.info("Forecasting database initialized successfully")
    except Exception as e:
        logger.error("Failed to initialize forecasting database", error=str(e))
        raise

async def get_db_health() -> bool:
    """Check database health"""
    try:
        async with async_engine.begin() as conn:
            await conn.execute(text("SELECT 1"))
        return True
    except Exception as e:
        logger.error("Database health check failed", error=str(e))
        return False

# Database manager instance for service_base compatibility
database_manager = DatabaseManager(
    database_url=settings.DATABASE_URL,
    service_name="forecasting-service",
    pool_size=10,
    max_overflow=20,
    echo=settings.DEBUG
)