"""
Async migrations handler for FastAPI application.
This file is separate from env.py to avoid Alembic context issues.
"""
import os
import sys
from sqlalchemy.ext.asyncio import create_async_engine
from sqlalchemy import pool

# Ensure the app directory is in the Python path
sys.path.insert(0, os.path.realpath(os.path.join(os.path.dirname(__file__), '..')))

from app.database import Base as DatabaseBase
from app.config import settings

async def run_migrations():
    """Run database migrations asynchronously."""
    from alembic.runtime.migration import MigrationContext
    from alembic.operations import Operations
    
    # Create async engine
    engine = create_async_engine(
        settings.DATABASE_URL,
        poolclass=pool.NullPool,
    )
    
    async with engine.connect() as connection:
        # Get current database schema version
        def do_get_current_rev(conn):
            migration_context = MigrationContext.configure(
                conn,
                opts={
                    'target_metadata': DatabaseBase.metadata,
                    'compare_type': True,
                    'compare_server_default': True
                }
            )
            return migration_context.get_current_revision()
        
        current_rev = await connection.run_sync(do_get_current_rev)
        
        # Run migrations
        def do_upgrade(conn):
            migration_context = MigrationContext.configure(
                conn,
                opts={
                    'target_metadata': DatabaseBase.metadata,
                    'compare_type': True,
                    'compare_server_default': True
                }
            )
            with Operations.context(migration_context):
                migration_context.run_migrations()
        
        await connection.run_sync(do_upgrade)
    
    await engine.dispose()