"""Alembic environment configuration for Mind v5.

Handles database migrations with support for:
- PostgreSQL with pgvector extension
- Async database connections
- Environment variable configuration
"""

import asyncio
import os
from logging.config import fileConfig

from alembic import context
from sqlalchemy import pool
from sqlalchemy.engine import Connection
from sqlalchemy.ext.asyncio import async_engine_from_config

# Alembic Config object
config = context.config

# Setup logging
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Target metadata for autogenerate support
# Import models here for autogenerate to detect changes
target_metadata = None

# Override SQLAlchemy URL from environment
def get_url() -> str:
    """Get database URL from environment or config."""
    return os.getenv(
        "DATABASE_URL",
        config.get_main_option("sqlalchemy.url"),
    )


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode.

    Generates SQL script without connecting to database.
    """
    url = get_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 connection."""
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
    )

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


async def run_async_migrations() -> None:
    """Run migrations in async mode."""
    configuration = config.get_section(config.config_ini_section)
    configuration["sqlalchemy.url"] = get_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.

    Creates connection and runs migrations.
    """
    asyncio.run(run_async_migrations())


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