UX: Show extra details in failure popup when translation fails (#262)

When we translate a newly created topic (therefore topic title and post content), we send both title and cooked in separately. There is a chance that the title cannot be translated, but the post can be translated. The error does not make it obvious on which content the error is happening. 

This commit makes it precise to the reader if it is the "topic's title" or "post's content".

Author: nattsw

app/services/discourse_translator/amazon.rb

@@ -134,7 +134,7 @@ def self.translate!(translatable, target_locale_sym = I18n.locale)
         )
       rescue Aws::Translate::Errors::UnsupportedLanguagePairException
         raise I18n.t(
-                "translator.failed",
+                "translator.failed.#{translatable.class.name.downcase}",
                 source_locale: detected_lang,
                 target_locale: target_locale_sym,
               )

app/services/discourse_translator/base.rb

@@ -42,7 +42,7 @@ def self.translate(translatable, target_locale_sym = I18n.locale)
       unless translate_supported?(detected_lang, target_locale_sym)
         raise TranslatorError.new(
                 I18n.t(
-                  "translator.failed",
+                  "translator.failed.#{translatable.class.name.downcase}",
                   source_locale: detected_lang,
                   target_locale: target_locale_sym,
                 ),

config/locales/server.en.yml

@@ -24,11 +24,14 @@ en:
     experimental_inline_translation: "Enable experimental inline translation feature. This replaces existing parallel translation, allowing site visitors with a non-default locale to view content in their language."
     automatic_translation_target_languages: "The languages to automatically translate user content (posts, topics) to. If empty, no languages will be automatically translated."
   translator:
-    failed: "The translator is unable to translate this content (%{source_locale}) to the default language of this site (%{target_locale})."
+    failed:
+      topic: "The translator is unable to translate this topic's title (%{source_locale}) to your language (%{target_locale})."
+      post: "The translator is unable to translate this post's content (%{source_locale}) to your language (%{target_locale})."
     not_supported: "This language is not supported by the translator."
     too_long: "This post is too long to be translated by the translator."
     not_available: "The translator service is currently not available."
     api_timeout: "The translator service took too long to respond. Please try again later."
+
     amazon:
       invalid_credentials: "The provided credentials for AWS translate are invalid."
 

spec/services/amazon_spec.rb

@@ -67,7 +67,7 @@
 
     it "raises an error when trying to translate an unsupported language" do
       expect { described_class.translate(post) }.to raise_error(
-        I18n.t("translator.failed", source_locale: "en", target_locale: "es"),
+        I18n.t("translator.failed.post", source_locale: "en", target_locale: "es"),
       )
     end
   end

spec/services/google_spec.rb

@@ -143,7 +143,7 @@
       )
 
       expect { described_class.translate(post) }.to raise_error(
-        I18n.t("translator.failed", source_locale: "cat", target_locale: "dog"),
+        I18n.t("translator.failed.post", source_locale: "cat", target_locale: "dog"),
       )
     end
 

spec/services/microsoft_spec.rb

@@ -169,7 +169,7 @@ def translate_endpoint
 
         expect { described_class.translate(post) }.to raise_error(
           DiscourseTranslator::TranslatorError,
-          I18n.t("translator.failed", source_locale: "donkey", target_locale: I18n.locale),
+          I18n.t("translator.failed.post", source_locale: "donkey", target_locale: I18n.locale),
         )
       end