feat(discord): Ability to change details of the game

Used to set the gameplay name (e.g. Josharias Survival, Metal Renegades, etc...)
It will show on discord in this format "Game: <name>"

- Improve the buffer change trigger and handler
- Ability to change details in the buffer
- Apply the new format for the rich presence
-- Details -> "Game: <name>"
-- Party State -> "Playing Solo" / "Playing Online" / "Hosting"

- Fix: Triggering `Thread#setEnabled` with keeping the connection alive
- Fix: No safe shutdown to the RPC thread

subsystems/DiscordRPC/src/main/java/org/terasology/engine/subsystem/discordrpc/DiscordRPCBuffer.java

@@ -11,14 +11,43 @@
  * It helps avoiding allocating unnecessary objects for the rich presence.
  */
 public final class DiscordRPCBuffer {
+    private String details;
     private String state;
     private OffsetDateTime startTimestamp;
     private boolean changed;
 
+    /**
+     * Resets the buffer data
+     */
+    public synchronized void reset() {
+        this.details = null;
+        this.state = null;
+        this.startTimestamp = null;
+        this.changed = true;
+    }
+
+    /**
+     * Sets the details of the current game
+     *
+     * @param details Details about the current game (null for nothing)
+     */
+    public synchronized void setDetails(String details) {
+        this.details = details;
+    }
+
+    /**
+     * Gets the details about the current game
+     *
+     * @return Detail about the current game
+     */
+    public synchronized String getDetails() {
+        return details;
+    }
+
     /**
      * Sets the current party status
      *
-     * @param state The current party status
+     * @param state The current party status (null for nothing)
      */
     public synchronized void setState(String state) {
         this.state = state;
@@ -62,6 +91,15 @@ public synchronized boolean hasChanged() {
         return changed;
     }
 
+    /**
+     * Check if the buffer is empty
+     *
+     * @return if the buffer is empty
+     */
+    public synchronized boolean isEmpty() {
+        return this.details == null && this.state == null && this.startTimestamp == null;
+    }
+
     /**
      * Resets the buffer's change state to false
      */

subsystems/DiscordRPC/src/main/java/org/terasology/engine/subsystem/discordrpc/DiscordRPCSubSystem.java

@@ -108,6 +108,21 @@ public static void discover() {
         getInstance().thread.discover();
     }
 
+    /**
+     * Resets the current rich presence data
+     */
+    public static void reset() {
+        getInstance().thread.getBuffer().reset();
+    }
+
+    /**
+     * Sets the name of the gameplay the player is playing (e.g. Custom, Josharias Survival, etc...)
+     * @param name the name of the gameplay
+     */
+    public static void setGameplayName(String name) {
+        getInstance().thread.getBuffer().setDetails("Game: " + name);
+    }
+
     /**
      * Sets the current game/party status for the player (e.g. Playing Solo, Idle, etc...)
      *

subsystems/DiscordRPC/src/main/java/org/terasology/engine/subsystem/discordrpc/DiscordRPCSystem.java

@@ -41,7 +41,8 @@ public void initialise() {
 
     @Override
     public void preBegin() {
-        DiscordRPCSubSystem.setState(getGame());
+        DiscordRPCSubSystem.setGameplayName("Custom");
+        DiscordRPCSubSystem.setState(getPartyState());
         DiscordRPCSubSystem.setStartTimestamp(null);
     }
 
@@ -52,6 +53,7 @@ public void postBegin() {
 
     @Override
     public void shutdown() {
+        DiscordRPCSubSystem.reset();
         DiscordRPCSubSystem.setState("In Main Menu");
         DiscordRPCSubSystem.setStartTimestamp(null);
     }
@@ -66,18 +68,18 @@ public void onAfk(AfkEvent event, EntityRef entityRef) {
             DiscordRPCSubSystem.setState("Idle");
             DiscordRPCSubSystem.setStartTimestamp(null);
         } else {
-            DiscordRPCSubSystem.setState(getGame());
+            DiscordRPCSubSystem.setState(getPartyState());
             DiscordRPCSubSystem.setStartTimestamp(OffsetDateTime.now());
         }
     }
 
-    public String getGame() {
+    public String getPartyState() {
         NetworkMode networkMode = networkSystem.getMode();
         String mode = "Playing Online";
         if (networkMode == NetworkMode.DEDICATED_SERVER) {
-            mode = "Hosting | " + game.getName();
+            mode = "Hosting";
         } else if (networkMode == NetworkMode.NONE) {
-            mode = "Solo | " + game.getName();
+            mode = "Playing Solo";
         }
         return mode;
     }

subsystems/DiscordRPC/src/main/java/org/terasology/engine/subsystem/discordrpc/DiscordRPCThread.java

@@ -54,15 +54,17 @@ public void start() {
     }
 
     public synchronized void stop() {
-        thread.interrupt();
+        synchronized (thread) {
+            thread.interrupt();
+        }
     }
 
-    public synchronized void discover()  {
+    public synchronized void discover() {
         if (enabled && connected) {
             return;
         }
 
-        reset();
+        reset(true);
 
         connectedBefore = true;
     }
@@ -73,8 +75,7 @@ public synchronized void enable() {
         }
 
         enabled = true;
-
-        reset();
+        autoReconnect = true;
 
         if (waiting && thread.isAlive()) {
             synchronized (thread) {
@@ -84,14 +85,20 @@ public synchronized void enable() {
     }
 
     public synchronized void disable() {
+        disable(false);
+    }
+
+    public synchronized void disable(boolean keepConnectionAlive) {
         if (!enabled) {
             return;
         }
 
         enabled = false;
 
-        reset();
-        autoReconnect = false;
+        reset(!keepConnectionAlive);
+        if (!keepConnectionAlive) {
+            autoReconnect = false;
+        }
 
         if (waiting && thread.isAlive()) {
             synchronized (thread) {
@@ -194,14 +201,17 @@ public void run() {
             /* Update the rich presence and keeping the connection alive */
             while (connected) {
                 synchronized (this) {
-                    /* Allocate a new rich presence when the buffer has changed */
-                    if (enabled && buffer.hasChanged()) {
-                        lastRichPresence = build();
-                        buffer.resetState();
-                    }
-
                     /* Ping the ipc connection with an rich presnece to keep the connection alive */
                     if (enabled) {
+                        /* Allocate a new rich presence when the buffer has changed */
+                        if (buffer.hasChanged() && buffer.isEmpty()) {
+                            lastRichPresence = null;
+                            buffer.resetState();
+                        } else if (buffer.hasChanged()) {
+                            lastRichPresence = build();
+                            buffer.resetState();
+                        }
+
                         ipcClient.sendRichPresence(lastRichPresence);
                     } else {
                         ipcClient.sendRichPresence(null);
@@ -221,6 +231,14 @@ public void run() {
     }
 
     public synchronized void setEnabled(boolean enabled) {
+        if (this.enabled != enabled) {
+            if (enabled) {
+                enable();
+            } else {
+                disable(true);
+            }
+        }
+
         this.enabled = enabled;
     }
 
@@ -235,16 +253,19 @@ public synchronized DiscordRPCBuffer getBuffer() {
     private RichPresence build() {
         return new RichPresence.Builder()
                 .setLargeImage(DISCORD_APP_DEFAULT_IMAGE)
+                .setDetails(buffer.getDetails())
                 .setState(buffer.getState())
                 .setStartTimestamp(buffer.getStartTimestamp())
                 .build();
     }
 
-    private void reset() {
+    private void reset(boolean resetConnection) {
         tries = 0;
 
         autoReconnect = true;
-        connectedBefore = false;
-        connected = false;
+        if (resetConnection) {
+            connectedBefore = false;
+            connected = false;
+        }
     }
 }