from __future__ import annotations

from dataclasses import dataclass, fields, replace
from typing import Literal


@dataclass
class ModelSettings:
    """Settings to use when calling an LLM.

    This class holds optional model configuration parameters (e.g. temperature,
    top_p, penalties, truncation, etc.).

    Not all models/providers support all of these parameters, so please check the API documentation
    for the specific model and provider you are using.
    """

    temperature: float | None = None
    """The temperature to use when calling the model."""

    top_p: float | None = None
    """The top_p to use when calling the model."""

    frequency_penalty: float | None = None
    """The frequency penalty to use when calling the model."""

    presence_penalty: float | None = None
    """The presence penalty to use when calling the model."""

    tool_choice: Literal["auto", "required", "none"] | str | None = None
    """The tool choice to use when calling the model."""

    parallel_tool_calls: bool | None = None
    """Whether to use parallel tool calls when calling the model.
    Defaults to False if not provided."""

    truncation: Literal["auto", "disabled"] | None = None
    """The truncation strategy to use when calling the model."""

    max_tokens: int | None = None
    """The maximum number of output tokens to generate."""

    store: bool | None = None
    """Whether to store the generated model response for later retrieval.
    Defaults to True if not provided."""

    def resolve(self, override: ModelSettings | None) -> ModelSettings:
        """Produce a new ModelSettings by overlaying any non-None values from the
        override on top of this instance."""
        if override is None:
            return self

        changes = {
            field.name: getattr(override, field.name)
            for field in fields(self)
            if getattr(override, field.name) is not None
        }
        return replace(self, **changes)
