"""Alembic 환경 설정 (async / asyncpg)

- settings.DATABASE_URL 에서 연결 문자열을 읽어 동기 드라이버(psycopg2) URL 로 변환
- 모델 메타데이터를 임포트해 autogenerate 지원
"""
import asyncio
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

# ── 프로젝트 루트를 sys.path 에 추가 (alembic.ini prepend_sys_path = .) ───────
import sys
import os

# backend/ 가 작업 디렉토리이므로 app 패키지를 바로 임포트 가능
sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))

from app.core.config import settings
from app.core.database import Base

# 모든 모델 임포트 — autogenerate 가 테이블을 인식하도록
import app.models.models  # noqa: F401

# ── alembic.ini 로거 설정 ─────────────────────────────────────────────────────
config = context.config
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# ── DB URL: asyncpg → psycopg2 (Alembic 동기 드라이버용) ────────────────────
_db_url = settings.DATABASE_URL
if "+asyncpg" in _db_url:
    _db_url = _db_url.replace("+asyncpg", "")
elif _db_url.startswith("postgresql://"):
    pass  # already sync-compatible
config.set_main_option("sqlalchemy.url", _db_url)

target_metadata = Base.metadata


# ── 오프라인 마이그레이션 ─────────────────────────────────────────────────────
def run_migrations_offline() -> None:
    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()


# ── 온라인 마이그레이션 (async) ───────────────────────────────────────────────
def do_run_migrations(connection: Connection) -> None:
    context.configure(connection=connection, target_metadata=target_metadata)
    with context.begin_transaction():
        context.run_migrations()


async def run_async_migrations() -> None:
    _async_url = settings.DATABASE_URL
    if not "+asyncpg" in _async_url:
        _async_url = _async_url.replace("postgresql://", "postgresql+asyncpg://")

    connectable = async_engine_from_config(
        {"sqlalchemy.url": _async_url},
        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()