Monitoring client connections (#941)

## Description:
Disconnected client detection :
If a client haven't send a ping to the server since more than 30 seconds
They will then be marked disconnected with a dedicated icon.
No action are yet taken, this allows for extensive in-game test before
adding the *consequences* of the player leaving the game.
I also added extensive unit tests, lessening the risk of regression for
the future.


![image](https://github.com/user-attachments/assets/884e5e99-15e8-4544-bd52-7524542cc82a)



## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:
theodoreleon.aetarax

---------

Co-authored-by: evanpelle <evanpelle@gmail.com>

src/client/graphics/layers/NameLayer.ts

@@ -2,6 +2,7 @@ import allianceIcon from "../../../../resources/images/AllianceIcon.svg";
 import allianceRequestBlackIcon from "../../../../resources/images/AllianceRequestBlackIcon.svg";
 import allianceRequestWhiteIcon from "../../../../resources/images/AllianceRequestWhiteIcon.svg";
 import crownIcon from "../../../../resources/images/CrownIcon.svg";
+import disconnectedIcon from "../../../../resources/images/DisconnectedIcon.svg";
 import embargoBlackIcon from "../../../../resources/images/EmbargoBlackIcon.svg";
 import embargoWhiteIcon from "../../../../resources/images/EmbargoWhiteIcon.svg";
 import nukeRedIcon from "../../../../resources/images/NukeIconRed.svg";
@@ -40,6 +41,7 @@ export class NameLayer implements Layer {
   private renders: RenderInfo[] = [];
   private seenPlayers: Set<PlayerView> = new Set();
   private traitorIconImage: HTMLImageElement;
+  private disconnectedIconImage: HTMLImageElement;
   private allianceRequestBlackIconImage: HTMLImageElement;
   private allianceRequestWhiteIconImage: HTMLImageElement;
   private allianceIconImage: HTMLImageElement;
@@ -61,6 +63,8 @@ export class NameLayer implements Layer {
   ) {
     this.traitorIconImage = new Image();
     this.traitorIconImage.src = traitorIcon;
+    this.disconnectedIconImage = new Image();
+    this.disconnectedIconImage.src = disconnectedIcon;
     this.allianceIconImage = new Image();
     this.allianceIconImage.src = allianceIcon;
     this.allianceRequestBlackIconImage = new Image();
@@ -370,6 +374,24 @@ export class NameLayer implements Layer {
       existingTraitor.remove();
     }
 
+    // Disconnected icon
+    const existingDisconnected = iconsDiv.querySelector(
+      '[data-icon="disconnected"]',
+    );
+    if (render.player.isDisconnected()) {
+      if (!existingDisconnected) {
+        iconsDiv.appendChild(
+          this.createIconElement(
+            this.disconnectedIconImage.src,
+            iconSize,
+            "disconnected",
+          ),
+        );
+      }
+    } else if (existingDisconnected) {
+      existingDisconnected.remove();
+    }
+
     // Alliance icon
     const existingAlliance = iconsDiv.querySelector('[data-icon="alliance"]');
     if (myPlayer !== null && myPlayer.isAlliedWith(render.player)) {

src/core/Schemas.ts

@@ -33,7 +33,8 @@ export type Intent =
   | BuildUnitIntent
   | EmbargoIntent
   | QuickChatIntent
-  | MoveWarshipIntent;
+  | MoveWarshipIntent
+  | MarkDisconnectedIntent;
 
 export type AttackIntent = z.infer<typeof AttackIntentSchema>;
 export type CancelAttackIntent = z.infer<typeof CancelAttackIntentSchema>;
@@ -56,6 +57,9 @@ export type TargetTroopRatioIntent = z.infer<
 export type BuildUnitIntent = z.infer<typeof BuildUnitIntentSchema>;
 export type MoveWarshipIntent = z.infer<typeof MoveWarshipIntentSchema>;
 export type QuickChatIntent = z.infer<typeof QuickChatIntentSchema>;
+export type MarkDisconnectedIntent = z.infer<
+  typeof MarkDisconnectedIntentSchema
+>;
 
 export type Turn = z.infer<typeof TurnSchema>;
 export type GameConfig = z.infer<typeof GameConfigSchema>;
@@ -166,6 +170,7 @@ const BaseIntentSchema = z.object({
     "attack",
     "cancel_attack",
     "spawn",
+    "mark_disconnected",
     "boat",
     "cancel_boat",
     "name",
@@ -290,10 +295,16 @@ export const QuickChatIntentSchema = BaseIntentSchema.extend({
   variables: z.record(SafeString).optional(),
 });
 
+export const MarkDisconnectedIntentSchema = BaseIntentSchema.extend({
+  type: z.literal("mark_disconnected"),
+  isDisconnected: z.boolean(),
+});
+
 const IntentSchema = z.union([
   AttackIntentSchema,
   CancelAttackIntentSchema,
   SpawnIntentSchema,
+  MarkDisconnectedIntentSchema,
   BoatAttackIntentSchema,
   CancelBoatIntentSchema,
   AllianceRequestIntentSchema,

src/core/execution/ExecutionManager.ts

@@ -15,6 +15,7 @@ import { DonateTroopsExecution } from "./DonateTroopExecution";
 import { EmbargoExecution } from "./EmbargoExecution";
 import { EmojiExecution } from "./EmojiExecution";
 import { FakeHumanExecution } from "./FakeHumanExecution";
+import { MarkDisconnectedExecution } from "./MarkDisconnectedExecution";
 import { MoveWarshipExecution } from "./MoveWarshipExecution";
 import { NoOpExecution } from "./NoOpExecution";
 import { QuickChatExecution } from "./QuickChatExecution";
@@ -120,6 +121,8 @@ export class Executor {
           intent.quickChatKey,
           intent.variables ?? {},
         );
+      case "mark_disconnected":
+        return new MarkDisconnectedExecution(player, intent.isDisconnected);
       default:
         throw new Error(`intent type ${intent} not found`);
     }

src/core/execution/MarkDisconnectedExecution.ts

@@ -0,0 +1,24 @@
+import { Execution, Game, Player } from "../game/Game";
+
+export class MarkDisconnectedExecution implements Execution {
+  constructor(
+    private player: Player,
+    private isDisconnected: boolean,
+  ) {}
+
+  init(mg: Game, ticks: number): void {
+    this.player.markDisconnected(this.isDisconnected);
+  }
+
+  tick(ticks: number): void {
+    return;
+  }
+
+  isActive(): boolean {
+    return false;
+  }
+
+  activeDuringSpawnPhase(): boolean {
+    return false;
+  }
+}

src/core/game/Game.ts

@@ -433,6 +433,9 @@ export interface Player {
   largestClusterBoundingBox: { min: Cell; max: Cell } | null;
   lastTileChange(): Tick;
 
+  isDisconnected(): boolean;
+  markDisconnected(isDisconnected: boolean): void;
+
   hasSpawned(): boolean;
   setHasSpawned(hasSpawned: boolean): void;
 

src/core/game/GameUpdates.ts

@@ -103,6 +103,7 @@ export interface PlayerUpdate {
   smallID: number;
   playerType: PlayerType;
   isAlive: boolean;
+  isDisconnected: boolean;
   tilesOwned: number;
   gold: Gold;
   population: number;

src/core/game/GameView.ts

@@ -289,6 +289,9 @@ export class PlayerView {
   hasSpawned(): boolean {
     return this.data.hasSpawned;
   }
+  isDisconnected(): boolean {
+    return this.data.isDisconnected;
+  }
 }
 
 export class GameView implements GameMap {

src/core/game/PlayerImpl.ts

@@ -98,6 +98,7 @@ export class PlayerImpl implements Player {
   public _outgoingLandAttacks: Attack[] = [];
 
   private _hasSpawned = false;
+  private _isDisconnected = false;
 
   constructor(
     private mg: GameImpl,
@@ -135,6 +136,7 @@ export class PlayerImpl implements Player {
       smallID: this.smallID(),
       playerType: this.type(),
       isAlive: this.isAlive(),
+      isDisconnected: this.isDisconnected(),
       tilesOwned: this.numTilesOwned(),
       gold: this._gold,
       population: this.population(),
@@ -919,6 +921,14 @@ export class PlayerImpl implements Player {
     return this._lastTileChange;
   }
 
+  isDisconnected(): boolean {
+    return this._isDisconnected;
+  }
+
+  markDisconnected(isDisconnected: boolean): void {
+    this._isDisconnected = isDisconnected;
+  }
+
   hash(): number {
     return (
       simpleHash(this.id()) * (this.population() + this.numTilesOwned()) +

src/server/Client.ts

@@ -4,7 +4,8 @@ import { Tick } from "../core/game/Game";
 import { ClientID } from "../core/Schemas";
 
 export class Client {
-  public lastPing: number;
+  public lastPing: number = Date.now();
+  public isDisconnected: boolean = false;
 
   public hashes: Map<Tick, number> = new Map();
 

src/server/GameServer.ts

@@ -35,6 +35,8 @@ export class GameServer {
 
   private maxGameDuration = 3 * 60 * 60 * 1000; // 3 hours
 
+  private disconnectedTimeout = 1 * 30 * 1000; // 30 seconds
+
   private turns: Turn[] = [];
   private intents: Intent[] = [];
   public activeClients: Client[] = [];
@@ -164,6 +166,10 @@ export class GameServer {
         });
         return;
       }
+
+      client.isDisconnected = existing.isDisconnected;
+      client.lastPing = existing.lastPing;
+
       existing.ws.removeAllListeners("message");
       this.activeClients = this.activeClients.filter((c) => c !== existing);
     }
@@ -195,6 +201,12 @@ export class GameServer {
               );
               return;
             }
+            if (clientMsg.intent.type === "mark_disconnected") {
+              this.log.warn(
+                `Should not receive mark_disconnected intent from client`,
+              );
+              return;
+            }
             this.addIntent(clientMsg.intent);
           }
           if (clientMsg.type === "ping") {
@@ -357,6 +369,7 @@ export class GameServer {
     this.intents = [];
 
     this.handleSynchronization();
+    this.checkDisconnectedStatus();
 
     let msg = "";
     try {
@@ -537,6 +550,36 @@ export class GameServer {
     }
   }
 
+  private checkDisconnectedStatus() {
+    if (this.turns.length % 5 !== 0) {
+      return;
+    }
+
+    const now = Date.now();
+    for (const [clientID, client] of this.allClients) {
+      if (
+        client.isDisconnected === false &&
+        now - client.lastPing > this.disconnectedTimeout
+      ) {
+        this.markClientDisconnected(client, true);
+      } else if (
+        client.isDisconnected &&
+        now - client.lastPing < this.disconnectedTimeout
+      ) {
+        this.markClientDisconnected(client, false);
+      }
+    }
+  }
+
+  private markClientDisconnected(client: Client, isDisconnected: boolean) {
+    client.isDisconnected = isDisconnected;
+    this.addIntent({
+      type: "mark_disconnected",
+      clientID: client.clientID,
+      isDisconnected: isDisconnected,
+    });
+  }
+
   private archiveGame() {
     this.log.info("archiving game", {
       gameID: this.id,