from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool
from sqlalchemy.engine.url import URL

from alembic import context

from intranet.domenator.src.db import db
from intranet.domenator.src.settings import config as app_config


# 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.
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 = db

# 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.


def _get_config():
    base_config = config.get_section(config.config_ini_section)

    base_config['sqlalchemy.url'] = str(
        URL(
            drivername=app_config.db_drivername,
            username=app_config.db_username,
            password=app_config.db_password,
            host=app_config.db_master_host,
            port=app_config.db_port,
            database=app_config.db_name,
        )
    )
    return base_config


def run_migrations_offline():
    """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_config()["sqlalchemy.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():
    """Run migrations in 'online' mode.

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

    """

    connectable = engine_from_config(
        _get_config(),
        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()
