"""Alembic 迁移环境：从 core.config 取连接串，metadata 由全部模型填充。"""

import os
import sys
from logging.config import fileConfig

from alembic import context
from sqlalchemy import create_mock_engine, engine_from_config, pool

# 将 src 加入 sys.path（与 scripts/init_db.py 一致），使 core / modules 可导入
_SRC_DIR = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "src")


def _setup_src_path():
    if _SRC_DIR not in sys.path:
        sys.path.insert(0, _SRC_DIR)


_setup_src_path()

from core.config import SQLALCHEMY_DATABASE_URL
from core.database import Base
# 加载全部模型以填充 metadata（create_app 会连带导入所有业务模块）
from core.app import create_app

create_app()

config = context.config

# set_section_option 不做 % 插值，避免 URL 中特殊字符被 configparser 转义
# 取当前活跃驱动连接串（DB_DRIVER 切换后 alembic 自动跟随）
config.set_section_option("alembic", "sqlalchemy.url", SQLALCHEMY_DATABASE_URL)

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

target_metadata = Base.metadata


def run_migrations_offline() -> None:
    """离线模式：不连库，将迁移编译为 SQL 输出。"""
    url = config.get_main_option("sqlalchemy.url")
    if url.startswith("mssql"):
        # 上游 bug workaround：mssql 离线渲染列注释时 dialect.default_schema_name 为 None
        # （离线无服务器探活），quote_schema(None) 触发 AttributeError；显式补 'dbo' 可完整渲染。
        # create_mock_engine 把原始 DDL 构造体交给 executor，须用同一 dialect 编译成真正 SQL。
        def _dump_mssql(sql, *multiparams, **params):
            print(sql.compile(dialect=mock_connection.dialect, literal_binds=True))

        mock_connection = create_mock_engine(url, _dump_mssql)
        mock_connection.dialect.default_schema_name = "dbo"
        context.configure(
            connection=mock_connection,
            target_metadata=target_metadata,
            literal_binds=True,
        )
    else:
        context.configure(
            url=url,
            target_metadata=target_metadata,
            literal_binds=True,
            dialect_opts={"paramstyle": "named"},
        )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """在线模式：连接数据库执行迁移。"""
    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)
        with context.begin_transaction():
            context.run_migrations()


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