"""Alembic env.py — async migration runner for Chrysopedia."""

import asyncio
import os
import sys
from logging.config import fileConfig

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

# Ensure the backend package is importable
# When running locally: alembic/ sits beside backend/, so ../backend works
# When running in Docker: alembic/ is inside /app/ alongside the backend modules
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "backend"))
sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))

from database import Base  # noqa: E402
import models  # noqa: E402, F401  — registers all tables on Base.metadata

config = context.config

if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata

# Allow DATABASE_URL env var to override alembic.ini
url_override = os.getenv("DATABASE_URL")
if url_override:
    config.set_main_option("sqlalchemy.url", url_override)


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode — emit SQL to stdout."""
    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):
    context.configure(connection=connection, target_metadata=target_metadata)
    with context.begin_transaction():
        context.run_migrations()


async def run_async_migrations() -> None:
    """Run migrations in 'online' mode with an async engine."""
    connectable = async_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()


def run_migrations_online() -> None:
    asyncio.run(run_async_migrations())


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