"""Alembic 迁移环境（支持 async MySQL + 同步运行）"""
import os
import sys
from logging.config import fileConfig

from sqlalchemy import engine_from_config, pool
from alembic import context

# 把 backend/ 加入 Python 路径，让 app.* 可以被 import
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

# 读取 .env
from dotenv import load_dotenv
load_dotenv(os.path.join(os.path.dirname(os.path.dirname(__file__)), ".env"))

# 导入所有模型，让 autogenerate 能发现
from app.core.models import Base  # noqa: F401  — 触发所有模型注册

# Alembic Config
config = context.config

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

target_metadata = Base.metadata

# ── 从环境变量构造同步连接串（Alembic 使用同步驱动）──────────────
def get_url() -> str:
    host = os.getenv("DB_HOST", "localhost")
    port = os.getenv("DB_PORT", "3306")
    name = os.getenv("DB_NAME", "sme_omnistore")
    user = os.getenv("DB_USER", "sme_user")
    pwd  = os.getenv("DB_PASSWORD", "sme_pass123")
    return f"mysql+pymysql://{user}:{pwd}@{host}:{port}/{name}?charset=utf8mb4"


def run_migrations_offline() -> None:
    """离线模式：只生成 SQL，不执行"""
    url = get_url()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """在线模式：连接数据库并执行迁移"""
    cfg = config.get_section(config.config_ini_section, {})
    cfg["sqlalchemy.url"] = get_url()

    connectable = engine_from_config(
        cfg,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )
    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            compare_type=True,
        )
        with context.begin_transaction():
            context.run_migrations()


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