# Copyright (c) 2023 Lincoln Stein (https://github.com/lstein) and the InvokeAI Development Team

"""
Base class for the InvokeAI configuration system.
It defines a type of pydantic BaseSettings object that
is able to read and write from an omegaconf-based config file,
with overriding of settings from environment variables and/or
the command line.
"""

from __future__ import annotations

import argparse
import pydoc
from dataclasses import dataclass
from typing import Any, Callable, TypeAlias

from packaging.version import Version


class PagingArgumentParser(argparse.ArgumentParser):
    """
    A custom ArgumentParser that uses pydoc to page its output.
    It also supports reading defaults from an init file.
    """

    def print_help(self, file=None) -> None:
        text = self.format_help()
        pydoc.pager(text)


AppConfigDict: TypeAlias = dict[str, Any]

MigrationFunction: TypeAlias = Callable[[AppConfigDict], AppConfigDict]


@dataclass
class MigrationEntry:
    """Defines an individual migration."""

    from_version: Version
    to_version: Version
    function: MigrationFunction

    def __hash__(self) -> int:
        # Callables are not hashable, so we need to implement our own __hash__ function to use this class in a set.
        return hash((self.from_version, self.to_version))