working rfid, more player capabilities

src/DirectoryNode.cpp

@@ -122,6 +122,36 @@ void DirectoryNode::advanceToFirstMP3InThisNode() {
     }
 }
 
+DirectoryNode* DirectoryNode::advanceToMP3(const String* currentGlobal) {
+    for (auto subdir : subdirectories)
+    {
+        if (subdir->getName()==*currentGlobal) {
+            subdir->advanceToFirstMP3InThisNode();
+            return subdir;
+        }   
+
+        // Have each subdirectory advance its song
+        for (size_t i = 0; i < subdir->mp3Files.size(); i++)
+        {
+            if (*currentGlobal == subdir->mp3Files[i])
+            {
+                // Found the current MP3 file
+                if (i < subdir->mp3Files.size() - 1)
+                {
+                    subdir->currentPlaying = &subdir->mp3Files[i];
+                    return subdir;
+                } 
+
+            }
+        }
+    }
+
+    // If we get here, there were no MP3 files or subdirectories left to check
+    currentPlaying = nullptr;
+    Serial.println("no more nodes found");
+    return this;
+}
+
 DirectoryNode* DirectoryNode::advanceToNextMP3(const String* currentGlobal)
 {
     bool useFirst = false;