from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = None

# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.

import os
from alembic import context
from sqlalchemy import create_engine
# 导入 resource 数据库的 Base（包含所有表定义）
from models.resources import ResourceBase
target_metadata = ResourceBase.metadata  # 关联 MySQL 模型的元数据

def get_mysql_url():
    evn = os.environ.get('DB_ENV', 'dev')
    if evn.lower() == 'dev':
        return "mysql+pymysql://root:mysqlpw@testdb:3306/resources"
    elif evn.lower() == 'nas':  
        return "mysql+pymysql://root:root@mariadb:3306/resources"
    else:
        return "mysql+pymysql://root:mysqlpw@testdb:3306/resources"


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = get_mysql_url()
    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:
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """

    #ini_section = config.get_section_option(config.config_ini_section, "ini_section", fallback="dev")
    #url = config.get_section_option(ini_section, "sqlalchemy.url")
    #connectable = create_engine(url)
    url = get_mysql_url()
    connectable = create_engine(url)

    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()