slayer: fix forgetting initial amount on disconnect

The server zeros the varps on login after a disconnect, causing the
plugin to clear the task. Setting amount=0 avoids this. Also set
loginFlag etc like the other gamestate changes  to avoid the infobox
being readded on login.

Co-authored-by: sam <[email protected]>

runelite-client/src/main/java/net/runelite/client/plugins/slayer/SlayerPlugin.java

@@ -257,11 +257,15 @@ public void onGameStateChanged(GameStateChanged event)
 	{
 		switch (event.getGameState())
 		{
+			// client (or with CONNECTION_LOST, the server...) will soon zero the slayer varps.
+			// zero task/amount so that this doesn't cause the plugin to reset the task, which
+			// would forget the initial amount. The vars are then resynced shortly after
 			case HOPPING:
 			case LOGGING_IN:
+			case CONNECTION_LOST:
 				taskName = "";
 				amount = 0;
-				loginFlag = true;
+				loginFlag = true; // to reinitialize initialAmount and avoid re-adding the infobox
 				targets.clear();
 				break;
 		}

runelite-client/src/test/java/net/runelite/client/plugins/slayer/SlayerPluginTest.java

@@ -56,6 +56,7 @@
 import net.runelite.client.ui.overlay.OverlayManager;
 import net.runelite.client.ui.overlay.infobox.InfoBoxManager;
 import org.junit.After;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import org.junit.Before;
@@ -298,4 +299,60 @@ private boolean matches(final String npcName, final Task task)
 		slayerPlugin.setTask(task.getName(), 0, 0);
 		return slayerPlugin.isTarget(npc);
 	}
+
+	@Test
+	public void testDisconnect()
+	{
+		when(client.getVarpValue(VarPlayer.SLAYER_TASK_SIZE)).thenReturn(42);
+		when(client.getVarpValue(VarPlayer.SLAYER_TASK_CREATURE)).thenReturn(1);
+		when(client.getEnum(EnumID.SLAYER_TASK_CREATURE))
+			.thenAnswer(a ->
+			{
+				EnumComposition e = mock(EnumComposition.class);
+				when(e.getStringValue(anyInt())).thenReturn("mocked npc");
+				return e;
+			});
+
+		// initial amount is fetched from config at sync
+		when(configManager.getRSProfileConfiguration("slayer", "initialAmount", int.class)).thenReturn(99);
+
+		slayerPlugin.setTaskName("mocked npc");
+		slayerPlugin.setAmount(42);
+		slayerPlugin.setInitialAmount(99);
+
+		// Disconnect looks like:
+		// gs connection_lost
+		// gs logged_in
+		// varp=0
+		// varp=value
+
+		GameStateChanged connectionLost = new GameStateChanged();
+		connectionLost.setGameState(GameState.CONNECTION_LOST);
+		slayerPlugin.onGameStateChanged(connectionLost);
+
+		GameStateChanged loggedIn = new GameStateChanged();
+		loggedIn.setGameState(GameState.LOGGED_IN);
+		slayerPlugin.onGameStateChanged(loggedIn);
+
+		when(client.getVarpValue(VarPlayer.SLAYER_TASK_SIZE)).thenReturn(0);
+		when(client.getVarpValue(VarPlayer.SLAYER_TASK_CREATURE)).thenReturn(0);
+
+		VarbitChanged taskSizeChanged = new VarbitChanged();
+		taskSizeChanged.setVarpId(VarPlayer.SLAYER_TASK_SIZE);
+		slayerPlugin.onVarbitChanged(taskSizeChanged);
+
+		VarbitChanged taskCreatureChanged = new VarbitChanged();
+		taskCreatureChanged.setVarpId(VarPlayer.SLAYER_TASK_CREATURE);
+		slayerPlugin.onVarbitChanged(taskCreatureChanged);
+
+		when(client.getVarpValue(VarPlayer.SLAYER_TASK_SIZE)).thenReturn(42);
+		when(client.getVarpValue(VarPlayer.SLAYER_TASK_CREATURE)).thenReturn(1);
+
+		slayerPlugin.onVarbitChanged(taskSizeChanged);
+		slayerPlugin.onVarbitChanged(taskCreatureChanged);
+
+		assertEquals("mocked npc", slayerPlugin.getTaskName());
+		assertEquals(42, slayerPlugin.getAmount());
+		assertEquals(99, slayerPlugin.getInitialAmount());
+	}
 }