defmodule LangChain.Chain do
  @moduledoc """
  A chain of ChainLinks to be processed in order, usually ending in an anchor for user confirmation.
  """

  @derive Jason.Encoder
  defstruct [
    links: []  # List of ChainLinks, processed in order

  ]

  @doc """
  Creates a new Chain struct with the given chain_links.
  """
  def new(chain_links) do
    %LangChain.Chain{
      links: chain_links
    }
  end

  @doc """
  Processes the ChainLinks in the chain and accumulates the output.
  If the optional `anchor` parameter is set to `true`, an anchor step will be added at the end of the chain for user confirmation.
  """
  def call(lang_chain, previous_values, anchor \\ false) do
    # Use Enum.reduce to process the ChainLinks and accumulate the output in previous_values

    result = Enum.reduce(lang_chain.links, previous_values, fn chain_link, acc ->
      updated_chain_link = LangChain.ChainLink.call(chain_link, acc)
      # Merge the output of the current ChainLink with the accumulated previous values

      Map.merge(acc, updated_chain_link.output)
    end)

    if anchor do
      case LangChain.Anchor.confirm(:query, result) do
        :yes -> result
        :no -> {:error, "User declined"}
      end
    else
      result
    end
  end
end