refactored translator service API design

aspnetcore/src/DbLocalizationProvider.AdminUI.AspNetCore/Areas/4D5A2189D188417485BF6C70546D34A1/Pages/AdminUI.cshtml

@@ -831,8 +831,8 @@
                 axios
                     .get('api/service/auto-translate?inputText=' + this.model.currentResource.invariant + '&targetLanguage=' + this.model.currentResource.language)
                     .then(response => {
-                        if (response) {
-                            this.model.currentResource.translation = response.data;
+                        if (response && response.data.isSuccessful) {
+                            this.model.currentResource.translation = response.data.result;
                         }
                     });
             },

aspnetcore/src/DbLocalizationProvider.AdminUI.AspNetCore/Areas/4D5A2189D188417485BF6C70546D34A1/Pages/AdminUITree.cshtml

@@ -532,8 +532,8 @@
                 axios
                     .get('../api/service/auto-translate?inputText=' + this.currentResource.invariant + '&targetLanguage=' + this.currentResource.language)
                     .then(response => {
-                        if (response) {
-                            this.currentResource.translation = response.data;
+                        if (response && response.data.isSuccessful) {
+                            this.currentResource.translation = response.data.result;
                         }
                     });
             },

aspnetcore/src/DbLocalizationProvider.AdminUI.AspNetCore/ServiceController.cs

@@ -154,9 +154,12 @@ public async Task<IActionResult> AutoTranslate(string inputText, string targetLa
             return BadRequest("Translator service is not configured.");
         }
 
-        var resultText = await translator.TranslateAsync(inputText, targetLanguage);
+        var result = await translator.TranslateAsync(
+            inputText,
+            CultureInfo.GetCultureInfo(targetLanguage),
+            CultureInfo.InvariantCulture);
 
-        return Ok(resultText);
+        return Ok(result);
     }
 
     private LocalizationResourceApiModel PrepareViewModel(string keyword)

common/src/DbLocalizationProvider.Abstractions/ITranslatorService.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using System.Threading.Tasks;
 
 namespace DbLocalizationProvider.Abstractions;
@@ -11,7 +12,8 @@ public interface ITranslatorService
     /// Translates text from one language to another.
     /// </summary>
     /// <param name="inputText">Text to translate.</param>
-    /// <param name="targetLanguage">Target language code to translate text to.</param>
+    /// <param name="targetLanguage">Target language to translate text to.</param>
+    /// <param name="sourceLanguage">Source language to translate text from.</param>
     /// <returns>Translated text if all is good; otherwise <c>null</c>.</returns>
-    Task<string> TranslateAsync(string inputText, string targetLanguage);
+    Task<TranslationResult> TranslateAsync(string inputText, CultureInfo targetLanguage, CultureInfo sourceLanguage);
 }

common/src/DbLocalizationProvider.Abstractions/TranslationResult.cs

@@ -0,0 +1,40 @@
+namespace DbLocalizationProvider.Abstractions;
+
+/// <summary>
+/// Result of the translation operation from AI service.
+/// </summary>
+/// <param name="IsSuccessful">Is operation successful?</param>
+/// <param name="Result">Translated text to target language.</param>
+/// <param name="Error">Filled in with problem details if any.</param>
+public record TranslationResult(bool IsSuccessful, string? Result, Problem? Error = null)
+{
+    /// <summary>
+    /// Translation was successful.
+    /// </summary>
+    /// <param name="text">Translated text to target language.</param>
+    /// <returns>Successful translation result.</returns>
+    public static TranslationResult Ok(string text)
+    {
+        return new TranslationResult(true, text);
+    }
+
+    /// <summary>
+    /// Translation was failing.
+    /// </summary>
+    /// <param name="message">Error details if translation failed.</param>
+    /// <param name="details">More details about an error.</param>
+    /// <returns>Failed translation result.</returns>
+    public static TranslationResult Failed(string message, string? details = null)
+    {
+        return new TranslationResult(false, null, new Problem(message, details));
+    }
+}
+
+/// <summary>
+/// More details about failed translation.
+/// </summary>
+/// <param name="Message">Message about an error.</param>
+/// <param name="Details">More information about an error.</param>
+public record Problem(string? Message, string? Details)
+{
+}

common/src/DbLocalizationProvider.Translator.Azure/CognitiveServiceTranslator.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using Azure;
 using Azure.AI.Translation.Text;
 using DbLocalizationProvider.Abstractions;
@@ -26,24 +27,34 @@ public CognitiveServiceTranslator(IOptions<CognitiveServicesOptions> options, IL
     }
 
     /// <inheritdoc />
-    public async Task<string?> TranslateAsync(string inputText, string targetLanguage)
+    public async Task<TranslationResult> TranslateAsync(string inputText, CultureInfo targetLanguage, CultureInfo sourceLanguage)
     {
         AzureKeyCredential credential = new(_options.AccessKey);
         TextTranslationClient client = new(credential, _options.Region);
 
         try
         {
-            var response = await client.TranslateAsync(targetLanguage, inputText).ConfigureAwait(false);
+            var response = await client.TranslateAsync(targetLanguage.Name, inputText).ConfigureAwait(false);
             var translations = response.Value;
-            var translation = translations.FirstOrDefault();
 
-            return translation?.Translations?.FirstOrDefault()?.Text;
+            if (translations == null)
+            {
+                return TranslationResult.Failed("Failed to translate. Result from Azure Cognitive Service is null.");
+            }
+
+            var translation = translations[0]!;
+
+            if (translation.Translations == null || translation.Translations?.Count == 0)
+            {
+                return TranslationResult.Failed("Failed to translate. Translations from Azure Cognitive Service is null.");
+            }
+
+            return TranslationResult.Ok(translation.Translations[0].Text);
         }
         catch (RequestFailedException exception)
         {
             _logger.Error($"Failed to auto-translate to `{targetLanguage}`.", exception);
+            return TranslationResult.Failed($"Failed to translate. {exception.Message}");
         }
-
-        return default;
     }
 }