Improved error handling for model loading (#732)

app/MindWork AI Studio/Provider/Google/ProviderGoogle.cs

@@ -1,4 +1,3 @@
-using System.Net.Http.Headers;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Text.Json;
@@ -107,7 +106,7 @@ public class ProviderGoogle() : BaseProvider(LLMProviders.GOOGLE, "https://gener
             // Set the content:
             request.Content = new StringContent(embeddingRequest, Encoding.UTF8, "application/json");
             
-            using var response = await this.httpClient.SendAsync(request, token);
+            using var response = await this.HttpClient.SendAsync(request, token);
             var responseBody = await response.Content.ReadAsStringAsync(token);
         
             if (!response.IsSuccessStatusCode)
@@ -139,80 +138,64 @@ public class ProviderGoogle() : BaseProvider(LLMProviders.GOOGLE, "https://gener
     }
 
     /// <inheritdoc />
-    public override async Task<IEnumerable<Model>> GetTextModels(string? apiKeyProvisional = null, CancellationToken token = default)
+    public override async Task<ModelLoadResult> GetTextModels(string? apiKeyProvisional = null, CancellationToken token = default)
     {
-        var models = await this.LoadModels(SecretStoreType.LLM_PROVIDER, token, apiKeyProvisional);
-        return models.Where(model =>
-                model.Id.StartsWith("gemini-", StringComparison.OrdinalIgnoreCase) &&
-                !this.IsEmbeddingModel(model.Id))
-            .Select(this.WithDisplayNameFallback);
+        var result = await this.LoadModels(SecretStoreType.LLM_PROVIDER, token, apiKeyProvisional);
+        return result with
+        {
+            Models =
+            [
+                ..result.Models.Where(model =>
+                        model.Id.StartsWith("gemini-", StringComparison.OrdinalIgnoreCase) &&
+                        !this.IsEmbeddingModel(model.Id))
+                    .Select(this.WithDisplayNameFallback)
+            ]
+        };
     }
 
     /// <inheritdoc />
-    public override Task<IEnumerable<Model>> GetImageModels(string? apiKeyProvisional = null, CancellationToken token = default)
+    public override Task<ModelLoadResult> GetImageModels(string? apiKeyProvisional = null, CancellationToken token = default)
     {
-        return Task.FromResult(Enumerable.Empty<Model>());
+        return Task.FromResult(ModelLoadResult.FromModels([]));
     }
 
-    public override async Task<IEnumerable<Model>> GetEmbeddingModels(string? apiKeyProvisional = null, CancellationToken token = default)
+    public override async Task<ModelLoadResult> GetEmbeddingModels(string? apiKeyProvisional = null, CancellationToken token = default)
     {
-        var models = await this.LoadModels(SecretStoreType.EMBEDDING_PROVIDER, token, apiKeyProvisional);
-        return models.Where(model => this.IsEmbeddingModel(model.Id))
-            .Select(this.WithDisplayNameFallback);
+        var result = await this.LoadModels(SecretStoreType.EMBEDDING_PROVIDER, token, apiKeyProvisional);
+        return result with
+        {
+            Models =
+            [
+                ..result.Models.Where(model => this.IsEmbeddingModel(model.Id))
+                    .Select(this.WithDisplayNameFallback)
+            ]
+        };
     }
     
     /// <inheritdoc />
-    public override Task<IEnumerable<Model>> GetTranscriptionModels(string? apiKeyProvisional = null, CancellationToken token = default)
+    public override Task<ModelLoadResult> GetTranscriptionModels(string? apiKeyProvisional = null, CancellationToken token = default)
     {
-        return Task.FromResult(Enumerable.Empty<Model>());
+        return Task.FromResult(ModelLoadResult.FromModels([]));
     }
     
     #endregion
 
-    private async Task<IReadOnlyList<Model>> LoadModels(SecretStoreType storeType, CancellationToken token, string? apiKeyProvisional = null)
+    private Task<ModelLoadResult> LoadModels(SecretStoreType storeType, CancellationToken token, string? apiKeyProvisional = null)
     {
-        var secretKey = apiKeyProvisional switch
-        {
-            not null => apiKeyProvisional,
-            _ => await RUST_SERVICE.GetAPIKey(this, storeType) switch
-            {
-                { Success: true } result => await result.Secret.Decrypt(ENCRYPTION),
-                _ => null,
-            }
-        };
-
-        if (string.IsNullOrWhiteSpace(secretKey))
-            return [];
-
-        using var request = new HttpRequestMessage(HttpMethod.Get, "models");
-        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", secretKey);
-        
-        using var response = await this.httpClient.SendAsync(request, token);
-        if(!response.IsSuccessStatusCode)
-        {
-            LOGGER.LogError("Failed to load models with status code {ResponseStatusCode} and body: '{ResponseBody}'.", response.StatusCode, await response.Content.ReadAsStringAsync(token));
-            return [];
-        }
-
-        try
-        {
-            var modelResponse = await response.Content.ReadFromJsonAsync<ModelsResponse>(token);
-            if (modelResponse == default || modelResponse.Data.Count is 0)
-            {
-                LOGGER.LogError("Google model list response did not contain a valid data array.");
-                return [];
-            }
-
-            return modelResponse.Data
+        return this.LoadModelsResponse<ModelsResponse>(
+            storeType,
+            "models",
+            modelResponse => modelResponse.Data
                 .Where(model => !string.IsNullOrWhiteSpace(model.Id))
-                .Select(model => new Model(this.NormalizeModelId(model.Id), model.DisplayName))
-                .ToArray();
-        }
-        catch (Exception e)
-        {
-            LOGGER.LogError("Failed to parse Google model list response: '{Message}'.", e.Message);
-            return [];
-        }
+                .Select(model => new Model(this.NormalizeModelId(model.Id), model.DisplayName)),
+            token,
+            apiKeyProvisional,
+            failureReasonSelector: (response, _) => response.StatusCode switch
+            {
+                System.Net.HttpStatusCode.Forbidden => ModelLoadFailureReason.AUTHENTICATION_OR_PERMISSION_ERROR,
+                System.Net.HttpStatusCode.Unauthorized => ModelLoadFailureReason.INVALID_OR_MISSING_API_KEY,
+                _ => ModelLoadFailureReason.PROVIDER_UNAVAILABLE,
+            });
     }
 
     private bool IsEmbeddingModel(string modelId)