suspend playlist engine while auto-change is active

* adding suspendPlaylist() to playlist engine code
* autoplaylist usermod calls suspendPlaylist() before switching to another preset
* fix a potential overflow on `lfc` (uint8_t -> uint16_t)

usermods/usermod_v2_auto_playlist/usermod_v2_auto_playlist.h

@@ -113,7 +113,7 @@ class AutoPlaylistUsermod : public Usermod {
       
       energy /= ENERGY_SCALE; // scale down so we get 0 sometimes
 
-      uint8_t lfc = float(fftResult[0]) * fftDeScaler[0] / 0.85f; // might as well undo pink noise here too.
+      uint16_t lfc = float(fftResult[0]) * fftDeScaler[0] / 0.85f; // might as well undo pink noise here too.
       uint16_t zcr = *(uint16_t*)um_data->u_data[11];
 
       // WLED-MM/TroyHacks: Calculate the long- and short-running averages
@@ -244,8 +244,7 @@ class AutoPlaylistUsermod : public Usermod {
             // go into freefall - this logic stops that from triggering right
             // after change_lockout. Better for smaller change_lockout values.
 
-            // SH7: this method is sub-optimal, as its interfering with the "playlist" engine
-            //       we shoud find a better method for triggering playlist changes
+            suspendPlaylist();       // suspend the playlist engine before changing to another preset
             applyPreset(newpreset);
             
             #ifdef USERMOD_AUTO_PLAYLIST_DEBUG

wled00/fcn_declare.h

@@ -208,6 +208,7 @@ void _overlayAnalogCountdown();
 void _overlayAnalogClock();
 
 //playlist.cpp
+void suspendPlaylist(); // WLEDMM support function for auto playlist usermod
 void shufflePlaylist();
 void unloadPlaylist();
 int16_t loadPlaylist(JsonObject playlistObject, byte presetId = 0);

wled00/playlist.cpp

@@ -41,6 +41,12 @@ void shufflePlaylist() {
   DEBUG_PRINTLN(F("Playlist shuffle."));
 }
 
+// WLEDMM supporting function for auto_playlist usermod
+//   prevents the active playlist from progressing (until it gets unloaded)
+static bool playlistSuspended = false;
+void suspendPlaylist() {
+  playlistSuspended = true;
+}
 
 void unloadPlaylist() {
   if (playlistEntries != nullptr) {
@@ -49,6 +55,7 @@ void unloadPlaylist() {
   }
   currentPlaylist = playlistIndex = -1;
   playlistLen = playlistEntryDur = playlistOptions = 0;
+  playlistSuspended = false;  // WLEDMM
   DEBUG_PRINTLN(F("Playlist unloaded."));
 }
 
@@ -125,6 +132,11 @@ void handlePlaylist() {
   // if fileDoc is not null JSON buffer is in use so just quit
   if (currentPlaylist < 0 || playlistEntries == nullptr || fileDoc != nullptr) return;
 
+  if (playlistSuspended) { // WLEDMM
+    if (millis() - presetCycledTime > (100*playlistEntryDur)) presetCycledTime = millis();   // keep updating timer
+    return; // but don't progress to next extry, and don't shuffle
+  }
+
   if (millis() - presetCycledTime > (100*playlistEntryDur)) {
     presetCycledTime = millis();
     if (bri == 0 || nightlightActive) return;