"""
SAAP Database Migrations - Alembic Environment
Production-ready database migration configuration
"""

import asyncio
import os
import sys
from logging.config import fileConfig
from sqlalchemy import engine_from_config, pool
from sqlalchemy.ext.asyncio import AsyncEngine
from alembic import context

# Add the backend directory to Python path
sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..'))

# Import SAAP models and settings
from database.models import Base
from config.settings import settings

# this is the Alembic Config object
config = context.config

# Interpret the config file for Python logging
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Set SQLAlchemy URL from environment/settings
config.set_main_option("sqlalchemy.url", settings.get_database_url())

# add your model's MetaData object here for 'autogenerate' support
target_metadata = Base.metadata

def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode.
    
    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well. By skipping the Engine creation
    we don't even need a DBAPI to be available.
    
    Calls to context.execute() here emit the given string to the
    script output.
    """
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def do_run_migrations(connection):
    """Run migrations with database connection"""
    context.configure(connection=connection, target_metadata=target_metadata)

    with context.begin_transaction():
        context.run_migrations()


async def run_migrations_online() -> None:
    """Run migrations in 'online' mode.
    
    In this scenario we need to create an Engine
    and associate a connection with the context.
    """
    
    connectable = AsyncEngine(
        engine_from_config(
            config.get_section(config.config_ini_section),
            prefix="sqlalchemy.",
            poolclass=pool.NullPool,
        )
    )

    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)

    await connectable.dispose()


if context.is_offline_mode():
    run_migrations_offline()
else:
    asyncio.run(run_migrations_online())