"""
Alembic environment configuration for async SQLAlchemy
"""
from logging.config import fileConfig
from sqlalchemy import pool
from sqlalchemy.engine import Connection
from sqlalchemy.ext.asyncio import async_engine_from_config

from alembic import context

# Import settings and models
import sys
from pathlib import Path

# Add project root to path
project_root = Path(__file__).parent.parent
sys.path.insert(0, str(project_root))

from shared.config import settings
from shared.database.models import Base

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Set target metadata for autogenerate
target_metadata = Base.metadata

# Override sqlalchemy.url from settings if not set in alembic.ini
if config.get_main_option("sqlalchemy.url") == "driver://user:pass@localhost/dbname":
    config.set_main_option("sqlalchemy.url", settings.DATABASE_URL)


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: Connection) -> None:
    """
    Run migrations with the given connection.
    """
    context.configure(
        connection=connection, 
        target_metadata=target_metadata,
        compare_type=False  # Disable autogenerate comparison to use explicit migration definitions
    )

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


async def run_async_migrations() -> None:
    """
    Run migrations in 'online' mode with async engine.
    """
    # Get database URL from settings
    database_url = settings.DATABASE_URL
    
    # Create async engine from config
    configuration = config.get_section(config.config_ini_section, {})
    configuration["sqlalchemy.url"] = database_url
    
    connectable = async_engine_from_config(
        configuration,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

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

    await connectable.dispose()


def run_migrations_online() -> None:
    """
    Run migrations in 'online' mode.
    
    For async SQLAlchemy, we use asyncio to run async migrations.
    """
    import asyncio
    
    asyncio.run(run_async_migrations())


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