Simplify client modes and add VAD retention policy

src/main.cpp

@@ -6,7 +6,6 @@
 #include "secrets.h"
 using namespace websockets;
 
-static constexpr bool kDefaultStreamMode = EVS_DEFAULT_STREAM_MODE;
 static constexpr bool kSerialCommandEcho = EVS_SERIAL_COMMAND_ECHO;
 static constexpr bool kMicUseRightChannel = EVS_MIC_USE_RIGHT_CHANNEL;
 static constexpr int kMicS24ToS16Shift = EVS_MIC_S24_TO_S16_SHIFT;
@@ -38,8 +37,7 @@ static constexpr float PI_F = 3.14159265358979323846f;
 
 enum class DeviceMode : uint8_t {
   Idle,
-  StreamToServer,  // Placeholder: ship PCM to remote STT/LLM/TTS service
-  LocalLoopback,   // Debug mode: mic directly to speaker
+  StreamToServer,  // Ship PCM to remote STT/LLM/TTS service
 };
 
 static DeviceMode g_mode = DeviceMode::Idle;
@@ -57,6 +55,8 @@ static size_t g_rxHead = 0;
 static size_t g_rxTail = 0;
 static size_t g_rxCount = 0;
 
+static void setMode(DeviceMode mode);
+
 static bool initMicI2s() {
   const i2s_config_t i2sConfig = {
       .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
@@ -207,18 +207,18 @@ static void onWsMessageCallback(WebsocketsMessage message) {
 static void onWsEventCallback(WebsocketsEvent event, String) {
   if (event == WebsocketsEvent::ConnectionOpened) {
     g_wsConnected = true;
-    if (g_mode == DeviceMode::StreamToServer && !g_streamingActive) {
-      g_ws.send("{\"type\":\"start\"}");
-      g_streamingActive = true;
-      playStartTone();
-    }
+    // Connection-driven mode: always stream on connect.
+    setMode(DeviceMode::StreamToServer);
     Serial.println("WS connected");
   } else if (event == WebsocketsEvent::ConnectionClosed) {
-    if (g_streamingActive) {
-      playStopTone();
-    }
+    const bool wasStreaming = g_streamingActive;
     g_wsConnected = false;
     g_streamingActive = false;
+    // Connection-driven mode: always idle on disconnect.
+    setMode(DeviceMode::Idle);
+    if (wasStreaming) {
+      playStopTone();
+    }
     Serial.println("WS disconnected");
   }
 }
@@ -352,13 +352,11 @@ static void serviceSpeaker() {
 static void printHelp() {
   Serial.println();
   Serial.println("Commands:");
-  Serial.println("  i = idle");
-  Serial.println("  s = stream mode");
-  Serial.println("  l = local loopback mode");
   Serial.println("  p = print network status");
   Serial.println("  h = help");
-  Serial.print("Default on boot: ");
-  Serial.println(kDefaultStreamMode ? "StreamToServer" : "LocalLoopback");
+  Serial.println("Connection policy:");
+  Serial.println("  connect -> StreamToServer (start)");
+  Serial.println("  disconnect -> Idle");
 }
 
 static void handleSerialCommands() {
@@ -368,22 +366,15 @@ static void handleSerialCommands() {
       Serial.print("RX cmd: ");
       Serial.println(c);
     }
-    if (c == 'i') {
-      setMode(DeviceMode::Idle);
-      Serial.println("Mode -> Idle");
-    } else if (c == 's') {
-      setMode(DeviceMode::StreamToServer);
-      Serial.println("Mode -> StreamToServer");
-    } else if (c == 'l') {
-      setMode(DeviceMode::LocalLoopback);
-      Serial.println("Mode -> LocalLoopback");
-    } else if (c == 'p') {
+    if (c == 'p') {
       Serial.print("WiFi: ");
       Serial.print((WiFi.status() == WL_CONNECTED) ? "connected " : "disconnected ");
       Serial.print("IP=");
       Serial.println(WiFi.localIP());
       Serial.print("WS: ");
       Serial.println(g_wsConnected ? "connected" : "disconnected");
+      Serial.print("Mode: ");
+      Serial.println((g_mode == DeviceMode::StreamToServer) ? "StreamToServer" : "Idle");
     } else if (c == 'h') {
       printHelp();
     } else if (c != '\r' && c != '\n') {
@@ -410,11 +401,8 @@ void setup() {
   g_ws.onEvent(onWsEventCallback);
   g_nextOutUs = micros();
 
-  if (kDefaultStreamMode) {
-    setMode(DeviceMode::StreamToServer);
-  } else {
-    setMode(DeviceMode::LocalLoopback);
-  }
+  // Wait in idle until WS connect event switches to StreamToServer.
+  setMode(DeviceMode::Idle);
   Serial.println("Audio init ok");
   Serial.println("Set local environment values in include/secrets.h");
   printHelp();
@@ -422,10 +410,8 @@ void setup() {
 
 void loop() {
   handleSerialCommands();
-  if (g_mode != DeviceMode::LocalLoopback) {
-    ensureConnectivity();
-    g_ws.poll();
-  }
+  ensureConnectivity();
+  g_ws.poll();
   serviceSpeaker();
 
   size_t bytesRead = 0;
@@ -444,10 +430,6 @@ void loop() {
   if (g_mode == DeviceMode::StreamToServer) {
     handleFrameForServer(pcm16, sampleCount);
     publishMicTelemetryIfDue(pcm16, sampleCount);
-  } else if (g_mode == DeviceMode::LocalLoopback) {
-    for (size_t i = 0; i < sampleCount; ++i) {
-      enqueuePcmSample(pcm16[i]);
-    }
   } else {
     // idle
   }