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

# Ensure project root is on sys.path for importing config.settings
PROJECT_ROOT = os.path.dirname(os.path.dirname(__file__))
if PROJECT_ROOT not in sys.path:
    sys.path.append(PROJECT_ROOT)

try:
    from config.settings import settings
except Exception:
    settings = None

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

target_metadata = None  # not used, explicit migrations only


def _get_urls():
    """Derive a sync SQLAlchemy URL from app settings (async -> sync)."""
    async_url = None
    sync_url = None
    if settings and getattr(settings, 'database_url', None):
        async_url = settings.database_url
        sync_url = async_url
        if async_url.startswith("postgresql+asyncpg://"):
            sync_url = async_url.replace("postgresql+asyncpg://", "postgresql://", 1)
    return async_url, sync_url


def run_migrations_offline():
    async_url, sync_url = _get_urls()
    url = sync_url or config.get_main_option("sqlalchemy.url")
    if url:
        config.set_main_option("sqlalchemy.url", url)
    context.configure(
        url=url,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

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


def run_migrations_online():
    async_url, sync_url = _get_urls()
    # If we have an async URL, run migrations via async engine
    if async_url and async_url.startswith("postgresql+asyncpg://"):
        async def do_run_migrations():
            connectable = create_async_engine(async_url, poolclass=pool.NullPool)
            async with connectable.connect() as connection:
                def sync_migrations(conn):
                    context.configure(connection=conn)
                    with context.begin_transaction():
                        context.run_migrations()

                await connection.run_sync(sync_migrations)

        import asyncio
        asyncio.run(do_run_migrations())
        return

    # Fallback to sync engine (e.g., if sync URL is provided)
    url = sync_url or config.get_main_option("sqlalchemy.url")
    if url:
        config.set_main_option("sqlalchemy.url", url)
    connectable = engine_from_config(
        config.get_section(config.config_ini_section),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(connection=connection)

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


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