"""Alembic 迁移环境。

设计要点：
1. 数据库 URL 从 ``POSTGRES_*`` 环境变量动态拼装，不污染 ``alembic.ini``；
2. 复用项目本身的 ORM metadata：``BaseDataModel.metadata`` 让 autogenerate
   能识别全部表；
3. 与运行期保持一致使用 ``asyncpg`` 异步驱动 —— 通过 ``async_engine_from_config``
   建立 AsyncEngine，再借 ``run_sync`` 把 alembic 的 sync migration 执行入口
   挂载进去。这样无需额外引入 psycopg 等同步驱动。
"""

from __future__ import annotations

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

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

PROJECT_ROOT = Path(__file__).resolve().parent.parent
if str(PROJECT_ROOT) not in sys.path:
    sys.path.insert(0, str(PROJECT_ROOT))

from kilostar.core.postgres_database.model.base import BaseDataModel  # noqa: E402
from kilostar.core.postgres_database import model as _model_pkg  # noqa: F401,E402

config = context.config

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


def _build_db_url() -> str:
    """从 ``POSTGRES_*`` 环境变量拼装一个 asyncpg URL。"""
    user = os.environ.get("POSTGRES_USER", "postgres")
    password = os.environ.get("POSTGRES_PASSWORD", "postgrespassword")
    host = os.environ.get("POSTGRES_HOST", "127.0.0.1")
    port = os.environ.get("POSTGRES_PORT", "5432")
    db = os.environ.get("POSTGRES_DB", "kilostar")
    return f"postgresql+asyncpg://{user}:{password}@{host}:{port}/{db}"


config.set_main_option("sqlalchemy.url", _build_db_url())

target_metadata = BaseDataModel.metadata


def run_migrations_offline() -> None:
    """离线模式：不连库，直接把 SQL 渲染到 stdout。"""
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
        compare_server_default=True,
    )
    with context.begin_transaction():
        context.run_migrations()


def _do_run_migrations(connection: Connection) -> None:
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        compare_type=True,
        compare_server_default=True,
    )
    with context.begin_transaction():
        context.run_migrations()


async def _run_async_migrations() -> None:
    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()