Added the ability to write context URI, Doesn't always work though

SpotifyDiyThing/SpotifyDiyThing.ino

@@ -27,6 +27,9 @@
 
 #define NFC_ENABLED 1
 
+// This causes issues in certain circumstances e.g. Play an album and let it auto play to related songs
+bool writeContextToNfc = true;
+
 // ----------------------------
 // Library Defines - Need to be defined before library import
 // ----------------------------
@@ -210,10 +213,18 @@ void loop()
 
   spotifyDisplay->checkForInput();
 
-#ifdef NFC_ENABLED
-  bool forceUpdate = nfcLoop(lastTrackUri);
-#else
   bool forceUpdate = false;
+
+#ifdef NFC_ENABLED
+  if (writeContextToNfc)
+  {
+    forceUpdate = nfcLoop(lastTrackUri, lastTrackContextUri);
+  }
+  else
+  {
+    forceUpdate = nfcLoop(lastTrackUri);
+  }
+
 #endif
 
   updateCurrentlyPlaying(forceUpdate);

SpotifyDiyThing/nfc.h

@@ -224,7 +224,7 @@ bool updateSpotify(char *tagContent)
   return false;
 }
 
-bool handleTag(const char *trackUri)
+bool handleTag(const char *trackUri, const char *contextUri)
 {
   NfcTag tag = nfc.read();
 
@@ -287,8 +287,6 @@ bool handleTag(const char *trackUri)
             Serial.println(uid);
           }
 
-          // Force the data into a String (might work depending on the content)
-          // Real code should use smarter processing
           char payloadAsString[payloadLength + 1];
           int numChars = 0;
           for (int c = 0; c < payloadLength; c++)
@@ -340,6 +338,7 @@ bool handleTag(const char *trackUri)
     Serial.println("Writing track");
 
     int trackLength = strlen(trackUri);
+    int contextLength = 0;
 
     NdefMessage message = NdefMessage();
     // This seems to be a blank card, lets write to it
@@ -351,14 +350,39 @@ bool handleTag(const char *trackUri)
     mimeType.getBytes(type, sizeof(type));
     r.setType(type, mimeType.length());
 
+    bool hasContext = false;
+
+    if (contextUri != NULL)
+    {
+      int contextLengthCheck = strlen(contextUri);
+
+      if (contextLengthCheck > 0)
+      {
+        hasContext = true;
+
+        // extra 1 for comma
+        contextLength = contextLengthCheck + 1;
+      }
+    }
+
+    // One for new line, one for the 0x00 needed at the start
+    int payloadLength = trackLength + contextLength + 2;
+
     // One for new line, one for the 0x00 needed at the start
-    byte payloadBytes[trackLength + 2];
+    byte payloadBytes[payloadLength];
     // Write to the new buffer offset by one
     // currentTrackUri.getBytes(&payloadBytes[1], trackLength + 1);
     memcpy(payloadBytes + sizeof(byte), trackUri, trackLength + 1);
     payloadBytes[0] = 0;
 
-    r.setPayload(payloadBytes, trackLength + 1);
+    if (hasContext)
+    {
+      payloadBytes[trackLength + 1] = ',';
+      // extra 1 for comma
+      memcpy(payloadBytes + (sizeof(byte) * (trackLength + 2)), contextUri, contextLength);
+    }
+
+    r.setPayload(payloadBytes, payloadLength - 1); // not sure why this is -1
 
     message.addRecord(r);
     boolean success = nfc.write(message);
@@ -379,12 +403,12 @@ bool handleTag(const char *trackUri)
   return false;
 }
 
-bool nfcLoop(const char *trackUri)
+bool nfcLoop(const char *trackUri, const char *contextUri = NULL)
 {
   forceUpdate = false;
   if (millis() > nfcDueTime)
   {
-    if (nfc.tagPresent() && handleTag(trackUri))
+    if (nfc.tagPresent() && handleTag(trackUri, contextUri))
     {
       Serial.println("Successful Read - Back to loop:");
       nfcDueTime = millis() + 5000; // 5 second cool down on NFC tag if succesful

SpotifyDiyThing/spotifyLogic.h

@@ -8,6 +8,7 @@ long songStartMillis;
 long songDuration;
 
 char lastTrackUri[200];
+char lastTrackContextUri[200];
 
 // You might want to make this much smaller, so it will update responsively
 
@@ -22,10 +23,14 @@ void spotifySetup(SpotifyDisplay *theDisplay, const char *clientId, const char *
   sp_Display = theDisplay;
   client.setCACert(spotify_server_cert);
   spotify.lateInit(clientId, clientSecret);
+
+  lastTrackUri[0] = '\0';
+  lastTrackContextUri[0] = '\0';
 }
 
 bool isSameTrack(const char *trackUri)
 {
+
   return strcmp(lastTrackUri, trackUri) == 0;
 }
 
@@ -34,6 +39,18 @@ void setTrackUri(const char *trackUri)
   strcpy(lastTrackUri, trackUri);
 }
 
+void setTrackContextUri(const char *trackContext)
+{
+  if (trackContext == NULL)
+  {
+    lastTrackContextUri[0] = '\0';
+  }
+  else
+  {
+    strcpy(lastTrackContextUri, trackContext);
+  }
+}
+
 void spotifyRefreshToken(const char *refreshToken)
 {
   spotify.setRefreshToken(refreshToken);
@@ -50,32 +67,33 @@ void spotifyRefreshToken(const char *refreshToken)
 
 void handleCurrentlyPlaying(CurrentlyPlaying currentlyPlaying)
 {
-
-  // printCurrentlyPlayingToSerial(currentlyPlaying);
-
-  if (!isSameTrack(currentlyPlaying.trackUri))
+  if (currentlyPlaying.trackUri != NULL)
   {
-    setTrackUri(currentlyPlaying.trackUri);
+    if (!isSameTrack(currentlyPlaying.trackUri))
+    {
+      setTrackUri(currentlyPlaying.trackUri);
+      setTrackContextUri(currentlyPlaying.contextUri);
 
-    // We have a new Song, need to update the text
-    sp_Display->printCurrentlyPlayingToScreen(currentlyPlaying);
-  }
+      // We have a new Song, need to update the text
+      sp_Display->printCurrentlyPlayingToScreen(currentlyPlaying);
+    }
 
-  albumArtChanged = sp_Display->processImageInfo(currentlyPlaying);
+    albumArtChanged = sp_Display->processImageInfo(currentlyPlaying);
 
-  sp_Display->displayTrackProgress(currentlyPlaying.progressMs, currentlyPlaying.durationMs);
+    sp_Display->displayTrackProgress(currentlyPlaying.progressMs, currentlyPlaying.durationMs);
 
-  if (currentlyPlaying.isPlaying)
-  {
-    // If we know at what millis the song started at, we can make a good guess
-    // at updating the progress bar more often than checking the API
-    songStartMillis = millis() - currentlyPlaying.progressMs;
-    songDuration = currentlyPlaying.durationMs;
-  }
-  else
-  {
-    // Song doesn't seem to be playing, do not update the progress
-    songStartMillis = 0;
+    if (currentlyPlaying.isPlaying)
+    {
+      // If we know at what millis the song started at, we can make a good guess
+      // at updating the progress bar more often than checking the API
+      songStartMillis = millis() - currentlyPlaying.progressMs;
+      songDuration = currentlyPlaying.durationMs;
+    }
+    else
+    {
+      // Song doesn't seem to be playing, do not update the progress
+      songStartMillis = 0;
+    }
   }
 }