prepare for tracking volume and play/pause locally

mpdclient.ino

@@ -29,6 +29,11 @@ struct song_info {
     String artist;
 };
 
+struct player_info {
+    int volume;
+    bool is_playing;
+};
+
 enum btn_flag { BTN_NONE, BTN_VOLUP, BTN_VOLDN, BTN_PAUSE, BTN_NEXT };
 
 btn_flag flag = BTN_NONE;
@@ -219,9 +224,10 @@ void volume_down() {
     send_command("volume -1");
 }
 
-int get_volume() {
+int get_player_info(player_info* player_info) {
     WiFiClient client;
     String vol_str;
+    String state_str;
 
     if (client.connect(MPDHOST, MPDPORT)) {
         Serial.println("connected");
@@ -235,6 +241,9 @@ int get_volume() {
                 if (line.startsWith("volume: ")) {
                     vol_str = line.substring(8);
                 }
+                else if (line.startsWith("state: ")) {
+                    state_str = line.substring(7);
+                }
                 else if (line.equals("OK")) {
                     client.stop();
                 }
@@ -247,10 +256,13 @@ int get_volume() {
     else {
         display_error("mpd connect failed");
         client.stop();
-        return -1;
+        return 1;
     }
 
-    return vol_str.toInt();
+    player_info->volume = vol_str.toInt();
+    player_info->is_playing = state_str.equals("play");
+
+    return 0;
 } 
 
 int get_song_info(song_info* song_info) {
@@ -290,7 +302,11 @@ int get_song_info(song_info* song_info) {
 }
 
 void display_volume() {
-    int volume = get_volume();
+    player_info pi;
+    if (get_player_info(&pi))
+        return;
+
+    int volume = pi.volume;
 
     display.clearDisplay();
     display.drawBitmap(0, 0, volume_icon, 32, 32, WHITE);