Added embedding API (#654)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

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

@@ -0,0 +1,6 @@
+namespace AIStudio.Provider.Google;
+
+public sealed record GoogleEmbedding
+{
+    public List<float>? Values { get; init; }
+}

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

@@ -0,0 +1,30 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace AIStudio.Provider.Google;
+
+public sealed record GoogleEmbeddingResponse
+{
+    [JsonConverter(typeof(GoogleEmbeddingListConverter))]
+    public List<GoogleEmbedding>? Embedding { get; init; }
+
+    private sealed class GoogleEmbeddingListConverter : JsonConverter<List<GoogleEmbedding>>
+    {
+        public override List<GoogleEmbedding> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType == JsonTokenType.StartObject)
+            {
+                var single = JsonSerializer.Deserialize<GoogleEmbedding>(ref reader, options);
+                return single is null ? new() : new() { single };
+            }
+
+            if (reader.TokenType == JsonTokenType.StartArray)
+                return JsonSerializer.Deserialize<List<GoogleEmbedding>>(ref reader, options) ?? new();
+
+            throw new JsonException("Expected object or array for embedding.");
+        }
+
+        public override void Write(Utf8JsonWriter writer, List<GoogleEmbedding> value, JsonSerializerOptions options) =>
+            JsonSerializer.Serialize(writer, value, options);
+    }
+}

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

@@ -87,6 +87,78 @@ public class ProviderGoogle() : BaseProvider(LLMProviders.GOOGLE, "https://gener
     {
         return Task.FromResult(string.Empty);
     }
+    
+    /// <inhertidoc />
+    public override async Task<IReadOnlyList<IReadOnlyList<float>>> EmbedTextAsync(Model embeddingModel, SettingsManager settingsManager, CancellationToken token = default, params List<string> texts)
+    {
+        var requestedSecret = await RUST_SERVICE.GetAPIKey(this, SecretStoreType.EMBEDDING_PROVIDER);
+        try
+        {
+            var modelName = embeddingModel.Id;
+            if (string.IsNullOrWhiteSpace(modelName))
+            {
+                LOGGER.LogError("No model name provided for embedding request.");
+                return [];
+            }
+
+            if (modelName.StartsWith("models/", StringComparison.OrdinalIgnoreCase))
+                modelName = modelName.Substring("models/".Length);
+
+            if (!requestedSecret.Success)
+            {
+                LOGGER.LogError("No valid API key available for embedding request.");
+                return [];
+            }
+            
+            // Prepare the Google Gemini embedding request:
+            var payload = new
+            {
+                content = new
+                {
+                    parts = texts.Select(text => new { text }).ToArray()
+                },
+                
+                taskType = "SEMANTIC_SIMILARITY"
+            };
+            
+            var embeddingRequest = JsonSerializer.Serialize(payload, JSON_SERIALIZER_OPTIONS);
+            var embedUrl = $"https://generativelanguage.googleapis.com/v1beta/models/{modelName}:embedContent";
+            using var request = new HttpRequestMessage(HttpMethod.Post, embedUrl);
+            request.Headers.Add("x-goog-api-key", await requestedSecret.Secret.Decrypt(ENCRYPTION));
+            
+            // Set the content:
+            request.Content = new StringContent(embeddingRequest, Encoding.UTF8, "application/json");
+            
+            using var response = await this.httpClient.SendAsync(request, token);
+            var responseBody = await response.Content.ReadAsStringAsync(token);
+        
+            if (!response.IsSuccessStatusCode)
+            {
+                LOGGER.LogError("Embedding request failed with status code {ResponseStatusCode} and body: '{ResponseBody}'.", response.StatusCode, responseBody);
+                return [];
+            }
+
+            var embeddingResponse = JsonSerializer.Deserialize<GoogleEmbeddingResponse>(responseBody, JSON_SERIALIZER_OPTIONS);
+            if (embeddingResponse is { Embedding: not null })
+            {
+                return embeddingResponse.Embedding
+                    .Select(d => d.Values?.ToArray() ?? [])
+                    .Cast<IReadOnlyList<float>>()
+                    .ToArray();
+            }
+            else
+            {
+                LOGGER.LogError("Was not able to deserialize the embedding response.");
+                return [];
+            }
+            
+        }
+        catch (Exception e)
+        {
+            LOGGER.LogError("Failed to perform embedding request: '{Message}'.", e.Message);
+            return [];
+        }
+    }
 
     /// <inheritdoc />
     public override async Task<IEnumerable<Model>> GetTextModels(string? apiKeyProvisional = null, CancellationToken token = default)