From a1c2c045108d5059421ad059eb4c1a56414af55a Mon Sep 17 00:00:00 2001
From: Blaz Kristan <blaz@kristan-sp.si>
Date: Fri, 5 Feb 2021 17:36:53 +0100
Subject: [PATCH] Playlist handling.

---
 wled00/json.cpp     |   2 +-
 wled00/playlist.cpp | 108 ++++++++++++++++++++++++++++++++++----------
 2 files changed, 84 insertions(+), 26 deletions(-)

diff --git a/wled00/json.cpp b/wled00/json.cpp
index 79d182f1..472ed44f 100644
--- a/wled00/json.cpp
+++ b/wled00/json.cpp
@@ -279,7 +279,7 @@ bool deserializeState(JsonObject root)
 
   JsonObject playlist = root[F("playlist")];
   if (!playlist.isNull()) {
-    loadPlaylist(playlist); return stateResponse;
+    loadPlaylist(playlist); //return stateResponse;
   }
 
   colorUpdated(noNotification ? NOTIFIER_CALL_MODE_NO_NOTIFY : NOTIFIER_CALL_MODE_DIRECT_CHANGE);
diff --git a/wled00/playlist.cpp b/wled00/playlist.cpp
index d94126c9..911e2692 100644
--- a/wled00/playlist.cpp
+++ b/wled00/playlist.cpp
@@ -10,19 +10,73 @@ typedef struct PlaylistEntry {
   uint16_t tr;
 } ple;
 
-byte playlistRepeat = 1;
-byte playlistEndPreset = 0;
-
-uint8_t* playlistEntries;
-
-byte playlistLen;
-int8_t playlistIndex = -1;
-
+int8_t   playlistRepeat = 1;
+byte     playlistEndPreset = 0;
+byte    *playlistEntries = nullptr;
+byte     playlistLen;
+int8_t   playlistIndex = -1;
 uint16_t playlistEntryDur = 0;
 
+
+void shufflePlaylist() {
+  int currentIndex = playlistLen, randomIndex;
+
+  PlaylistEntry temporaryValue, *entries = reinterpret_cast<PlaylistEntry*>(playlistEntries);
+
+  // While there remain elements to shuffle...
+  while (currentIndex--) {
+    // Pick a random element...
+    randomIndex = random(0, currentIndex);
+    // And swap it with the current element.
+    temporaryValue = entries[currentIndex];
+    entries[currentIndex] = entries[randomIndex];
+    entries[randomIndex] = temporaryValue;
+  }
+}
+
+/*
+ * The same thing as saving and loading playlist can be achieved using JSON API saved in a preset.
+ * 
+void deserializePlaylist() {
+  DynamicJsonDocument doc(JSON_BUFFER_SIZE);
+
+  DEBUG_PRINTLN(F("Reading playlist from /playlist.json..."));
+
+  if (!readObjectFromFile("/playlist.json", nullptr, &doc)) return; //if file does not exist just exit
+
+  JsonObject playlist = doc[F("playlist")];
+  if (!playlist.isNull()) loadPlaylist(playlist);
+}
+
+
+void serializePlaylist() {
+  DynamicJsonDocument doc(JSON_BUFFER_SIZE/8); // we don't need big buffer (>1k is ok)
+
+  DEBUG_PRINTLN(F("Writing playlist to /playlist.json..."));
+
+  PlaylistEntry* entries = reinterpret_cast<PlaylistEntry*>(playlistEntries);
+
+  JsonObject playlist = doc.createNestedObject(F("playlist"));
+  JsonArray ps = playlist.createNestedArray(F("ps"));
+  JsonArray dur = playlist.createNestedArray(F("dur"));
+  JsonArray tr = playlist.createNestedArray(F("transition"));
+  for (uint8_t i=0; i<playlistLen; i++) {
+    ps.add(entries[i].preset);
+    dur.add(entries[i].dur);
+    tr.add(entries[i].tr);
+  }
+  playlist[F("repeat")] = playlistRepeat; // TODO: this one is decreasing with each loop
+  playlist[F("end")] = playlistEndPreset;
+
+  File f = WLED_FS.open("/playlist.json", "w");
+  if (f) serializeJson(doc, f);
+  f.close();
+}
+*/
+
 void loadPlaylist(JsonObject playlistObj) {
-  delete playlistEntries;
-  playlistIndex = -1; playlistEntryDur = 0;
+  if (playlistEntries != nullptr) {delete[] playlistEntries; playlistEntries = nullptr;}
+  currentPlaylist = playlistIndex = -1; playlistEntryDur = 0;
   JsonArray presets = playlistObj["ps"];
   playlistLen = presets.size();
   if (playlistLen == 0) return;
@@ -72,26 +126,30 @@ void loadPlaylist(JsonObject playlistObj) {
   currentPlaylist = 0; //TODO here we need the preset ID where the playlist is saved
 }
 
-void handlePlaylist()
-{
+
+void handlePlaylist() {
   if (currentPlaylist < 0 || playlistEntries == nullptr || presetCyclingEnabled) return;
   
-  if (millis() - presetCycledTime > (100*playlistEntryDur))
-  {
+  if (millis() - presetCycledTime > (100*playlistEntryDur)) {
     presetCycledTime = millis();
     if (bri == 0 || nightlightActive) return;
 
-    playlistIndex++;
-    if (playlistIndex >= playlistLen) {
-      playlistIndex = 0;
-      if (playlistRepeat == 1) { //stop
-        currentPlaylist = -1;
-        delete playlistEntries;
-        playlistEntries = nullptr;
-        if (playlistEndPreset) applyPreset(playlistEndPreset);
-        return;
+    ++playlistIndex %= playlistLen; // -1 at 1st run (limit to playlistLen)
+
+    if (!playlistRepeat && !playlistIndex) { //stop if repeat == 0 and restart of playlist
+      currentPlaylist = -1;
+      delete[] playlistEntries;
+      playlistEntries = nullptr;
+      if (playlistEndPreset) applyPreset(playlistEndPreset);
+      return;
+    }
+    // playlist roll-over
+    if (!playlistIndex) {
+      if (playlistRepeat > 0) {// playlistRepeat < 0 => endless loop with shuffling presets
+        playlistRepeat--; // decrease repeat count on each index reset
+      } else {
+        shufflePlaylist();  // shuffle playlist and start over
       }
-      if (playlistRepeat > 1) playlistRepeat--;
     }
 
     PlaylistEntry* entries = reinterpret_cast<PlaylistEntry*>(playlistEntries);
@@ -103,4 +161,4 @@ void handlePlaylist()
     playlistEntryDur = entries[playlistIndex].dur;
     if (playlistEntryDur == 0) playlistEntryDur = 10;
   }
-}
\ No newline at end of file
+}