prompt_reader.rb

class PromptReader
  PROMPTS_DIR = Rails.root.join("app", "prompts")

  # Reads the content of a prompt file or Leva::Prompt object and renders it with Liquid templating
  #
  # @example Read a prompt file without Liquid templating
  #   PromptReader.read("welcome_message")
  #
  # @example Read a prompt file with Liquid templating
  #   PromptReader.read("greeting", name: "John")
  #
  # @example Read a prompt file in a subfolder
  #   PromptReader.read("chatbot/welcome_message")
  #   PromptReader.read("summaries/newsletter_summary_prompt")
  #
  # @example Read a Leva::Prompt object with Liquid templating
  #   leva_prompt = Leva::Prompt.find(1)
  #   PromptReader.read(leva_prompt, name: "John")
  #
  # @param prompt [String, Leva::Prompt] the name of the prompt file to read (without extension) or a Leva::Prompt object
  #   Can include subfolder paths like "folder/prompt_name"
  # @param options [Hash] optional parameters to render within the Liquid template
  # @return [String, nil] the content of the file or Leva::Prompt, rendered with Liquid templating, or nil if file does not exist
  def self.read(prompt, **options)
    content = if prompt.is_a?(Leva::Prompt)
      prompt.user_prompt
    else
      # Support for nested folders by directly joining the path with .md extension
      file_path = PROMPTS_DIR.join("#{prompt}.md")

      # If file doesn't exist, try to find it without adding .md (in case it already has an extension)
      unless File.exist?(file_path)
        alt_path = PROMPTS_DIR.join(prompt)
        file_path = alt_path if File.exist?(alt_path)
      end

      # Log the file path for debugging
      Rails.logger.debug("Looking for prompt at: #{file_path}")

      File.exist?(file_path) ? File.read(file_path) : nil
    end

    # Log if content is nil
    if content.nil?
      Rails.logger.warn("Prompt content is nil for: #{prompt}")
      return nil
    end

    if options.any?
      template = Liquid::Template.parse(content)
      # Ensure missing variables are left intact in the template
      template_vars = options.transform_keys(&:to_s)
      missing_keys = template.root.nodelist.select { |node| node.is_a?(Liquid::Variable) && !template_vars.key?(node.name.name) }.map { |node| node.name.name }
      missing_keys.each { |key| template_vars[key] = "{{ #{key} }}" }
      template.render(template_vars)
    else
      content
    end
  end
end