defmodule WiseGPTEx do
  @moduledoc """
  Documentation for `WiseGPTEx`.

  This module provides a function to obtain the best completion from the OpenAI models (default: "gpt-3.5-turbo") using the OpenAI API completions endpoint (`https://api.openai.com/v1/chat/completions`).
  The `get_best_completion/2` function takes a question and an optional list of options to configure the API request.

  ## Examples

  Basic usage:

      iex> WiseGPTEx.get_best_completion("What is the capital of France?")
      {:ok, "Paris"}

  Using all available options:

      iex> opts = [model: "gpt-4", temperature: 0.7, num_completions: 5, timeout: 300_000]
      iex> WiseGPTEx.get_best_completion("What is the capital of France?", opts)
      {:ok, "Paris"}

  ## Options

  The following options can be passed to the `get_best_completion/2` function:

    * `:model` - The name of the model to use (default: "gpt-3.5-turbo"). All OpenAI models are supported.
    * `:temperature` - Controls the randomness of the model's output. Higher values result in more diverse responses (default: 0.5).
    * `:num_completions` - The number of completions to generate (default: 3).
    * `:timeout` - The maximum time in milliseconds to wait for a response from the OpenAI API (default: 300_000 ms, or 5 minutes).

  """
  alias WiseGPTEx.OpenAIHTTPClient

  @spec get_best_completion(binary(), Keyword.t()) :: {:ok, binary()} | {:error, any()}
  def get_best_completion(_question, _opts \\ [])

  def get_best_completion(question, opts) when is_binary(question) do
    with {:ok, completions} <-
           OpenAIHTTPClient.get_completions_with_reasoning(question, opts),
         {:ok, best_completion_info} <-
           OpenAIHTTPClient.get_best_completion(question, completions, opts),
         {:ok, best_completion} <- pick_best_completion(completions, best_completion_info) do
      {:ok, best_completion}
    else
      {:error, reason} -> {:error, reason}
    end
  end

  def get_best_completion(_question, _opts), do: {:error, "the input must be a string"}

  defp pick_best_completion([first_completion | _] = completions, best_completion_info) do
    with %{"index" => index_str} <-
           Regex.named_captures(
             ~r/correct\s+answer:\s+(option\s+)?(?<index>\d+)/i,
             best_completion_info
           ),
         {index, _} <- Integer.parse(index_str),
         best_completion <- Enum.at(completions, index - 1, first_completion) do
      {:ok, best_completion}
    else
      _ ->
        # if we can't parse the index, just return the first completion
        {:ok, first_completion}
    end
  end
end