Allow aliases for deepl locales

If you only use the short locale name internally, you can use this commit in deepl to force a specific variant of the locale.

README.md

@@ -422,7 +422,7 @@ GOOGLE_TRANSLATE_API_KEY=<Google Translate API key>
 <a name="deepl-translation-config"></a>
 ### DeepL Pro Translate
 
-`i18n-tasks translate-missing` requires a DeepL Pro API key, get it at [DeepL](https://www.deepl.com/pro).
+`i18n-tasks translate-missing` requires a DeepL Pro API key, get it at [DeepL](https://www.deepl.com/pro). You can specify alias locales if you only use the simple locales internally.
 
 ```yaml
 # config/i18n-tasks.yml
@@ -436,6 +436,9 @@ translation:
     - 2c6415be-1852-4f54-9e1b-d800463496b4
   deepl_options:
     formality: prefer_less
+  deepl_locale_aliases:
+    en: en-us
+    pt: pt-br
 ```
 
 or via environment variables:

lib/i18n/tasks/translators/deepl_translator.rb

@@ -85,6 +85,9 @@ def to_deepl_source_locale(locale)
 
     # Convert 'es-ES' to 'ES' but warn about locales requiring a specific variant
     def to_deepl_target_locale(locale)
+      locale_aliases = @i18n_tasks.translation_config[:deepl_locale_aliases]
+      locale = locale_aliases[locale.to_s.downcase] || locale if locale_aliases.is_a?(Hash)
+
       loc, sub = locale.to_s.split('-')
       if SPECIFIC_TARGETS.include?(loc)
         # Must see how the deepl api evolves, so this could be an error in the future

spec/deepl_translate_spec.rb

@@ -81,4 +81,42 @@
       end
     end
   end
+
+  describe 'locale aliases' do
+    delegate :i18n_task, :in_test_app_dir, :run_cmd, to: :TestCodebase
+    let(:en) { { en: { hello: 'Hello' } } }
+    let(:config) do
+      { base_locale: 'en', locales: %w[pt], translation: { backend: 'deepl', deepl_locale_aliases: { pt: 'pt-br' } } }
+    end
+
+    before do
+      TestCodebase.setup(
+        'config/locales/en.yml' => en.to_yaml, 'config/locales/pt.yml' => '',
+        'config/i18n-tasks.yml' => config.to_yaml
+      )
+    end
+
+    after do
+      TestCodebase.teardown
+    end
+
+    context 'when configuration has pt=>pt-br' do
+      it 'uses pt-br instead of pt' do
+        skip 'DEEPL_AUTH_KEY env var not set' unless ENV['DEEPL_AUTH_KEY']
+
+        # rubocop:disable RSpec/StubbedMock
+        expect(DeepL).to receive(:translate).with(
+          ['Hello'],
+          'EN',
+          'PT-BR',
+          { html_escape: true, ignore_tags: ['i18n'], preserve_formatting: true, tag_handling: 'xml' }
+        ).and_raise('correct')
+        # rubocop:enable RSpec/StubbedMock
+
+        expect do
+          TestCodebase.run_cmd 'translate-missing'
+        end.to raise_error('correct')
+      end
+    end
+  end
 end