Shuffle the playlist before playing if "[random]" is in the rfid data.

include/controller.h

@@ -25,7 +25,7 @@ class Controller {
 	void next_track();
 	void prev_track();
 	void play();
-	void play(String rfid_id);
+	void play(String rfid_id, bool shuffle=false);
 	void stop();
 	void eof_mp3();
 };

include/playlist.h

@@ -22,4 +22,5 @@ class Playlist {
 	void restart();
 	void set_current_time(uint32_t time);
 	uint32_t get_current_time();
+	void shuffle();
 };

src/controller.cpp

@@ -67,7 +67,7 @@ void Controller::handle_rfid() {
 
 					String data = read_rfid_data();
 
-					play(s_uid);
+					play(s_uid, data.indexOf("[random]")>=0);
 				}
 				rfid->PICC_HaltA();
 			}
@@ -123,10 +123,14 @@ String Controller::read_rfid_data() {
 	return data;
 }
 
-void Controller::play(String rfid_id) {
+void Controller::play(String rfid_id, bool shuffle) {
 	if (!rfid_id.equals(current_playlist.get_rfid_id())) {
 		if (pm->has_playlist(rfid_id)) {
 			current_playlist = pm->get_playlist(rfid_id);
+			if (shuffle) {
+				log_i("Shuffling the playlist.");
+				current_playlist.shuffle();
+			}
 			play();
 		} else {
 			Serial.printf("There is no playlist for rfid_id %s\n", rfid_id.c_str());

src/playlist.cpp

@@ -60,3 +60,7 @@ void Playlist::set_current_time(uint32_t pos) {
 uint32_t Playlist::get_current_time() {
 	return current_time;
 }
+
+void Playlist::shuffle() {
+	std::random_shuffle(files.begin(), files.end());
+}