v2: add EmbeddingServerApp, fix Sendable issues (WIP)

Sources/MarkBaseServer/SimpleServerApp.swift

@@ -20,16 +20,36 @@ struct SimpleServerApp {
         print("")
 
         let engine = try MarkBaseEngine(autoCompile: true)
-        let model = try E4BModel(modelDir: modelPath, engine: engine, maxContextLength: 512)
+        
+        // Detect model type
+        let isEmbeddingGemma = modelName.contains("embeddinggemma") || modelName.contains("embedding")
+        let isE4B = !isEmbeddingGemma
+        
+        var e4bModel: E4BModel? = nil
+        var embedModel: EmbeddingGemmaModel? = nil
         let tokenizer = try TokenizerFactory.load(modelDir: modelPath)
-        let generator = StreamingGenerator(model: model, tokenizer: tokenizer, engine: engine)
-        let embeddingModel = try TextEmbeddingModel(modelDir: modelPath, engine: engine, config: TextEmbeddingConfig())
-
-        print("✓ E4B loaded (\(model.numHiddenLayers) layers)")
+        var generator: StreamingGenerator? = nil
+        
+        if isE4B {
+            e4bModel = try E4BModel(modelDir: modelPath, engine: engine, maxContextLength: 512)
+            generator = StreamingGenerator(model: e4bModel!, tokenizer: tokenizer, engine: engine)
+            print("✓ E4B loaded (\(e4bModel!.numHiddenLayers) layers)")
+        } else {
+            embedModel = try EmbeddingGemmaModel(modelDir: modelPath, engine: engine)
+            print("✓ EmbeddingGemma loaded (\(embedModel!.config.numHiddenLayers) layers, hidden=\(embedModel!.config.hiddenSize))")
+        }
+        
+        // Embedding model (use EmbeddingGemma if available, fallback to E4B)
+        let textEmbedModel: TextEmbeddingModel?
+        if isE4B {
+            textEmbedModel = try TextEmbeddingModel(modelDir: modelPath, engine: engine, config: TextEmbeddingConfig())
+        } else {
+            textEmbedModel = nil
+        }
 
         let router = Router()
 
-        let layers = model.numHiddenLayers
+        let layers = isE4B ? e4bModel!.numHiddenLayers : embedModel!.config.numHiddenLayers
 
         @Sendable func helpJSON() -> String {
             return """
@@ -184,7 +204,8 @@ struct SimpleServerApp {
         }
 
         @Sendable func healthResponse() -> String {
-            return "{\"status\":\"healthy\",\"model\":\"e4b\",\"layers\":\(layers)}"
+            let m = isEmbeddingGemma ? "embeddinggemma-300m" : "e4b"
+            return "{\"status\":\"healthy\",\"model\":\"\(m)\",\"layers\":\(layers)}"
         }
 
         router.get("/") { _, _ in
@@ -229,7 +250,7 @@ struct SimpleServerApp {
                 topP: topP
             )
 
-            let generatedTokens = try generator.generateTokens(promptTokens: promptTokens, config: config)
+            let generatedTokens = try generator!.generateTokens(promptTokens: promptTokens, config: config)
 
             let id = UUID().uuidString
             let ts = Int(Date().timeIntervalSince1970)
@@ -313,7 +334,14 @@ struct SimpleServerApp {
             var embeddings: [[String: Any]] = []
             for (i, text) in inputs.enumerated() {
                 let t0 = Date()
-                let embedding = try embeddingModel.embed(text: text)
+                let embedding: [Float]
+                if let eg = embedModelCopy {
+                    embedding = try eg.embed(text: text)
+                } else if let tem = textEmbedModelCopy {
+                    embedding = try tem.embed(text: text)
+                } else {
+                    return "{\"error\":\"no embedding model available\",\"type\":\"server_error\",\"code\":500}"
+                }
                 let duration = Date().timeIntervalSince(t0)
 
                 let embeddingData: [String: Any]
@@ -338,7 +366,7 @@ struct SimpleServerApp {
 
             let id = UUID().uuidString
             let ts = Int(Date().timeIntervalSince1970)
-            let totalTokens = inputs.reduce(0) { $0 + tokenizer.encode(text: $1).count }
+            let totalTokens = inputs.reduce(0) { $0 + $1.components(separatedBy: .whitespaces).count }
 
             let response: [String: Any] = [
                 "id": id,