defmodule LangChain.ScrapeChain do
  @moduledoc """
  Use this when you want to extract formatted data from natural-language text, ScrapeChain is basically
  a special form of QueryChain.
  ScrapeChain is a wrapper around a special type of Chain that requires 'inputSchema' and 'inputText' in its
  inputVariables and combines it with an outputParser.
  Once you define that chain, you can have the chain 'scrape' a text and return the
  formatted output in virtually any form.
  """

  @derive Jason.Encoder
  defstruct [
    chain: %LangChain.Chain{},
    inputSchema: "",
    outputParser: &LangChain.ScrapeChain.noParse/1
  ]

  def new(chain, inputSchema, outputParser \\ &LangChain.ScrapeChain.noParse/1) do
    %LangChain.ScrapeChain{
      chain: chain,
      inputSchema: inputSchema,
      outputParser: outputParser
    }
  end

  def scrape(scrape_chain, inputVariables) when is_map(inputVariables) do
    result = LangChain.Chain.call(scrape_chain.chain, inputVariables)
    # Parse the result using the outputParser

    scrape_chain.outputParser.(result)
  end

  def scrape(scrape_chain, input_text) when is_binary(input_text) do
    # Fill in the inputText and inputSchema values and run the Chain

    inputVariables = %{
      inputText: input_text,
      inputSchema: scrape_chain.inputSchema
    }
    result = LangChain.Chain.call(scrape_chain.chain, inputVariables)
    # Parse the result using the outputParser

    scrape_chain.outputParser.(result)
  end

  def noParse(result) do
    result
  end
end