"""Alembic 迁移环境配置

- 从 shared.config.settings 读取 DB 配置，构造同步 URL（psycopg2）供 alembic 使用
  （项目运行时用 asyncpg，但 alembic 是同步库，需 psycopg2）
- target_metadata 指向 shared.models.database.Base.metadata
- 支持 ALEMBIC_URL 环境变量覆盖（用于离线/空库生成初始迁移，如 sqlite:///empty.db）
"""
from logging.config import fileConfig
from pathlib import Path
import os
import sys

from sqlalchemy import engine_from_config, pool
from alembic import context

# 让 alembic 能 import 项目模块（src 在项目根下）
project_root = Path(__file__).parent.parent
sys.path.insert(0, str(project_root / "src"))

from shared.config.settings import settings  # noqa: E402
from shared.models.database import Base  # noqa: E402
import shared.models.database  # noqa: E402,F401  # 导入所有模型，确保 metadata 注册

config = context.config

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

# 构造同步 URL：asyncpg -> psycopg2
_sync_url = settings.DATABASE_URL.replace("postgresql+asyncpg://", "postgresql+psycopg2://")
# 支持 ALEMBIC_URL 覆盖（离线生成/测试用）
config.set_main_option("sqlalchemy.url", os.getenv("ALEMBIC_URL", _sync_url))

target_metadata = Base.metadata


def run_migrations_offline() -> None:
    """离线模式：生成 SQL 脚本，不连接 DB"""
    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 run_migrations_online() -> None:
    """在线模式：连接 DB 执行迁移"""
    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,
            target_metadata=target_metadata,
            compare_type=True,
            compare_server_default=True,
        )
        with context.begin_transaction():
            context.run_migrations()


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