# frozen_string_literal: true

module DiscourseAi
  module Completions
    module Dialects
      class ChatGpt < Dialect
        class << self
          def can_translate?(model_name)
            model_name.starts_with?("gpt-")
          end

          def tokenizer
            DiscourseAi::Tokenizer::OpenAiTokenizer
          end
        end

        VALID_ID_REGEX = /\A[a-zA-Z0-9_]+\z/

        def native_tool_support?
          true
        end

        def translate
          @embed_user_ids =
            prompt.messages.any? do |m|
              m[:id] && m[:type] == :user && !m[:id].to_s.match?(VALID_ID_REGEX)
            end

          super
        end

        def max_prompt_tokens
          # provide a buffer of 120 tokens - our function counting is not
          # 100% accurate and getting numbers to align exactly is very hard
          buffer = (opts[:max_tokens] || 2500) + 50

          if tools.present?
            # note this is about 100 tokens over, OpenAI have a more optimal representation
            @function_size ||= self.class.tokenizer.size(tools.to_json.to_s)
            buffer += @function_size
          end

          model_max_tokens - buffer
        end

        private

        def tools_dialect
          @tools_dialect ||= DiscourseAi::Completions::Dialects::OpenAiTools.new(prompt.tools)
        end

        def system_msg(msg)
          { role: "system", content: msg[:content] }
        end

        def model_msg(msg)
          { role: "assistant", content: msg[:content] }
        end

        def tool_call_msg(msg)
          tools_dialect.from_raw_tool_call(msg)
        end

        def tool_msg(msg)
          tools_dialect.from_raw_tool(msg)
        end

        def user_msg(msg)
          user_message = { role: "user", content: msg[:content] }

          if msg[:id]
            if @embed_user_ids
              user_message[:content] = "#{msg[:id]}: #{msg[:content]}"
            else
              user_message[:name] = msg[:id]
            end
          end

          user_message[:content] = inline_images(user_message[:content], msg)
          user_message
        end

        def inline_images(content, message)
          if model_name.include?("gpt-4-vision") || model_name == "gpt-4-turbo"
            content = message[:content]
            encoded_uploads = prompt.encoded_uploads(message)
            if encoded_uploads.present?
              new_content = []
              new_content.concat(
                encoded_uploads.map do |details|
                  {
                    type: "image_url",
                    image_url: {
                      url: "data:#{details[:mime_type]};base64,#{details[:base64]}",
                    },
                  }
                end,
              )
              new_content << { type: "text", text: content }
              content = new_content
            end
          end

          content
        end

        def per_message_overhead
          # open ai defines about 4 tokens per message of overhead
          4
        end

        def calculate_message_token(context)
          self.class.tokenizer.size(context[:content].to_s + context[:name].to_s)
        end

        def model_max_tokens
          case model_name
          when "gpt-3.5-turbo-16k"
            16_384
          when "gpt-4"
            8192
          when "gpt-4-32k"
            32_768
          when "gpt-4-turbo"
            131_072
          else
            8192
          end
        end
      end
    end
  end
end