# -*- coding: utf-8 -*-
# Copyright 2023 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Abstract interface for models."""
from __future__ import annotations

import abc
import dataclasses
from typing import Sequence


@dataclasses.dataclass(frozen=True)
class ModelArguments:
  """Common arguments for models.

  Attributes:
    model: The model string to use. If None a default model will be selected.
    temperature: The temperature. Must be greater-than-or-equal-to zero.
    candidate_count: Number of candidates to return.
  """

  model: str | None = None
  temperature: float | None = None
  candidate_count: int | None = None


@dataclasses.dataclass
class ModelResults:
  """Results from calling AbstractModel.call_model()."""

  model_input: str
  text_results: Sequence[str]


class AbstractModel(abc.ABC):

  @abc.abstractmethod
  def call_model(
      self, model_input: str, model_args: ModelArguments | None = None
  ) -> ModelResults:
    """Executes the model."""


class EchoModel(AbstractModel):
  """Model that returns the original input.

  This is primarily used for testing.
  """

  def call_model(
      self, model_input: str, model_args: ModelArguments | None = None
  ) -> ModelResults:
    candidate_count = model_args.candidate_count if model_args else None
    if candidate_count is None:
      candidate_count = 1
    return ModelResults(
        model_input=model_input, text_results=[model_input] * candidate_count
    )