FEATURE: Add discourse-ai as a translation provider

Author: nattsw

about.json

@@ -0,0 +1,7 @@
+{
+  "tests": {
+    "requiredPlugins": [
+      "https://github.com/discourse/discourse-ai"
+    ]
+  }
+}

app/services/discourse_translator/discourse_ai.rb

@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require_relative "base"
+require "json"
+
+module DiscourseTranslator
+  class DiscourseAi < Base
+    MAX_DETECT_LOCALE_TEXT_LENGTH = 1000
+    def self.language_supported?(_)
+      true
+    end
+
+    def self.detect(topic_or_post)
+      return unless required_settings_enabled
+
+      topic_or_post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] ||= begin
+        # we don't need that much text to determine the locale
+        text = get_text(topic_or_post).truncate(MAX_DETECT_LOCALE_TEXT_LENGTH)
+
+        get_ai_helper_output(
+          text,
+          CompletionPrompt.find_by(id: CompletionPrompt::DETECT_TEXT_LOCALE),
+        )
+      end
+    end
+
+    def self.translate(topic_or_post)
+      return unless required_settings_enabled
+
+      detected_lang = detect(topic_or_post)
+      translated_text =
+        from_custom_fields(topic_or_post) do
+          get_ai_helper_output(
+            get_text(topic_or_post),
+            CompletionPrompt.find_by(id: CompletionPrompt::TRANSLATE),
+          )
+        end
+
+      [detected_lang, translated_text]
+    end
+
+    private
+
+    def self.get_ai_helper_output(text, prompt)
+      ::DiscourseAi::AiHelper::Assistant.new.generate_and_send_prompt(
+        prompt,
+        text,
+        Discourse.system_user,
+      )[
+        :suggestions
+      ].first
+    end
+
+    def self.required_settings_enabled
+      SiteSetting.translator_enabled && SiteSetting.translator == "DiscourseAi" &&
+        SiteSetting.discourse_ai_enabled && SiteSetting.ai_helper_enabled
+    end
+  end
+end

config/locales/server.en.yml

@@ -28,6 +28,10 @@ en:
     microsoft:
       missing_token: "The translator was unable to retrieve a valid token."
       missing_key: "No Azure Subscription Key provided."
+
+    discourse_ai:
+      not_installed: "You need to install the discourse-ai plugin to use this feature."
+      ai_helper_required: 'You need to <a href="%{base_url}/admin/site_settings/category/all_results?filter=plugin%3Adiscourse-ai%20helper">configure the ai helper</a> to use this feature.'
   not_in_group:
     user_not_in_group: "You don't belong to a group allowed to translate."
     poster_not_in_group: "Post wasn't made by an user in an allowed group."

config/settings.yml

@@ -7,11 +7,13 @@ discourse_translator:
     client: true
     type: enum
     choices:
+      - DiscourseAi
       - Microsoft
       - Google
       - Amazon
       - Yandex
       - LibreTranslate
+    validator: "DiscourseTranslator::TranslatorSelectionValidator"
   translator_azure_subscription_key:
     default: ''
   translator_azure_region:

lib/discourse_translator/translator_selection_validator.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module DiscourseTranslator
+  class TranslatorSelectionValidator
+    def initialize(opts = {})
+      @opts = opts
+    end
+
+    def valid_value?(val)
+      return true if val.blank?
+
+      if val == "DiscourseAi"
+        return false if !defined?(DiscourseAutomation)
+        return false if !SiteSetting.ai_helper_enabled
+      end
+
+      true
+    end
+
+    def error_message
+      return I18n.t("translator.discourse_ai.not_installed") if !defined?(DiscourseAutomation)
+
+      I18n.t("translator.discourse_ai.ai_helper_required") if !SiteSetting.ai_helper_enabled
+    end
+  end
+end

plugin.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # name: discourse-translator
-# about: Translates posts on Discourse using Microsoft, Google, Yandex or LibreTranslate translation APIs.
+# about: Translates posts on Discourse using Microsoft, Google, Yandex, LibreTranslate, or Discourse AI translation APIs.
 # meta_topic_id: 32630
 # version: 0.3.0
 # authors: Alan Tan
@@ -31,7 +31,7 @@ module ::DiscourseTranslator
 
   topic_view_post_custom_fields_allowlister { [::DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD] }
 
-  reloadable_patch do |plugin|
+  reloadable_patch do
     Guardian.prepend(DiscourseTranslator::GuardianExtension)
     Post.prepend(DiscourseTranslator::PostExtension)
     Topic.prepend(DiscourseTranslator::TopicExtension)

spec/lib/translator_selection_validator_spec.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe ::DiscourseTranslator::TranslatorSelectionValidator do
+  subject { described_class.new }
+
+  fab!(:llm_model) { Fabricate(:llm_model) }
+
+  describe "#valid_value?" do
+    context "when value is blank" do
+      it "returns true" do
+        expect(subject.valid_value?(nil)).to eq(true)
+        expect(subject.valid_value?("")).to eq(true)
+      end
+    end
+
+    context "when value is 'DiscourseAi'" do
+      context "when DiscourseAutomation is not defined" do
+        it "returns false" do
+          hide_const("DiscourseAutomation")
+          expect(subject.valid_value?("DiscourseAi")).to eq(false)
+        end
+      end
+
+      context "when DiscourseAutomation is defined but ai_helper_enabled is false" do
+        it "returns false" do
+          SiteSetting.ai_helper_enabled = false
+          expect(subject.valid_value?("DiscourseAi")).to eq(false)
+        end
+      end
+
+      context "when DiscourseAutomation is defined and ai_helper_enabled is true" do
+        it "returns true" do
+          DiscourseAi::Completions::Llm.with_prepared_responses(["OK"]) do
+            SiteSetting.ai_helper_model = "custom:#{llm_model.id}"
+            SiteSetting.ai_helper_enabled = true
+          end
+          expect(subject.valid_value?("DiscourseAi")).to eq(true)
+        end
+      end
+    end
+
+    context "when value is not 'DiscourseAi'" do
+      it "returns true" do
+        expect(subject.valid_value?("googly")).to eq(true)
+        expect(subject.valid_value?("poopy")).to eq(true)
+      end
+    end
+  end
+
+  describe "#error_message" do
+    context "when DiscourseAutomation is not defined" do
+      it "returns the not_installed error message" do
+        hide_const("DiscourseAutomation")
+        expect(subject.error_message).to eq(I18n.t("translator.discourse_ai.not_installed"))
+      end
+    end
+
+    context "when DiscourseAutomation is defined but ai_helper_enabled is false" do
+      it "returns the ai_helper_required error message" do
+        SiteSetting.ai_helper_enabled = false
+        expect(subject.error_message).to eq(I18n.t("translator.discourse_ai.ai_helper_required"))
+      end
+    end
+
+    context "when DiscourseAutomation is defined and ai_helper_enabled is true" do
+      it "returns nil" do
+        DiscourseAi::Completions::Llm.with_prepared_responses(["OK"]) do
+          SiteSetting.ai_helper_model = "custom:#{llm_model.id}"
+          SiteSetting.ai_helper_enabled = true
+        end
+        expect(subject.error_message).to be_nil
+      end
+    end
+  end
+end

spec/services/discourse_ai_spec.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe DiscourseTranslator::DiscourseAi do
+  before do
+    SiteSetting.translator_enabled = true
+    Fabricate(:fake_model).tap do |fake_llm|
+      SiteSetting.public_send("ai_helper_model=", "custom:#{fake_llm.id}")
+    end
+  end
+
+  describe ".detect" do
+    let(:post) { Fabricate(:post) }
+
+    it "stores the detected language in a custom field" do
+      locale = "de"
+      DiscourseAi::Completions::Llm.with_prepared_responses(["<output>de</output>"]) do
+        DiscourseTranslator::DiscourseAi.detect(post)
+      end
+
+      expect(post.custom_fields[DiscourseTranslator::DETECTED_LANG_CUSTOM_FIELD]).to eq locale
+    end
+
+    it "truncates to MAX LENGTH" do
+      truncated_text = post.cooked.truncate(DiscourseTranslator::DiscourseAi::MAX_DETECT_LOCALE_TEXT_LENGTH)
+      expect_any_instance_of(::DiscourseAi::AiHelper::Assistant)
+        .to receive(:generate_and_send_prompt)
+              .with(
+                CompletionPrompt.find_by(id: CompletionPrompt::DETECT_TEXT_LOCALE),
+                truncated_text,
+                Discourse.system_user
+              ).and_call_original
+
+      DiscourseAi::Completions::Llm.with_prepared_responses(["<output>de</output>"]) do
+        DiscourseTranslator::DiscourseAi.detect(post)
+      end
+    end
+
+    it "returns if settings are not correct" do
+
+    end
+  end
+
+  describe ".translate" do
+    it "translates the post and returns [locale, translated_text]" do
+      post = Fabricate(:post)
+      DiscourseAi::Completions::Llm.with_prepared_responses(["<output>some translated text</output>", "<output>translated</output>"]) do
+        locale, translated_text = DiscourseTranslator::DiscourseAi.translate(post)
+        expect(locale).to eq "de"
+        expect(translated_text).to eq "some translated text"
+      end
+    end
+  end
+end