Implement vote for winner (#2013)

## Description:

Require majority of ips to report a winner.

## 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

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

evan

src/server/Client.ts

@@ -1,13 +1,15 @@
 import WebSocket from "ws";
 import { TokenPayload } from "../core/ApiSchemas";
 import { Tick } from "../core/game/Game";
-import { ClientID } from "../core/Schemas";
+import { ClientID, Winner } from "../core/Schemas";
 
 export class Client {
   public lastPing: number = Date.now();
 
   public hashes: Map<Tick, number> = new Map();
 
+  public reportedWinner: Winner | null = null;
+
   constructor(
     public readonly clientID: ClientID,
     public readonly persistentID: string,

src/server/GameServer.ts

@@ -64,6 +64,11 @@ export class GameServer {
 
   private websockets: Set<WebSocket> = new Set();
 
+  private winnerVotes: Map<
+    string,
+    { winner: ClientSendWinnerMessage; ips: Set<string> }
+  > = new Map();
+
   constructor(
     public readonly id: string,
     readonly log_: Logger,
@@ -184,6 +189,7 @@ export class GameServer {
       }
 
       client.lastPing = existing.lastPing;
+      client.reportedWinner = existing.reportedWinner;
 
       this.activeClients = this.activeClients.filter((c) => c !== existing);
     }
@@ -283,15 +289,7 @@ export class GameServer {
             break;
           }
           case "winner": {
-            if (
-              this.outOfSyncClients.has(client.clientID) ||
-              this.kickedClients.has(client.clientID) ||
-              this.winner !== null
-            ) {
-              return;
-            }
-            this.winner = clientMsg;
-            this.archiveGame();
+            this.handleWinner(client, clientMsg);
             break;
           }
           default: {
@@ -793,4 +791,48 @@ export class GameServer {
       outOfSyncClients,
     };
   }
+
+  private handleWinner(client: Client, clientMsg: ClientSendWinnerMessage) {
+    if (
+      this.outOfSyncClients.has(client.clientID) ||
+      this.kickedClients.has(client.clientID) ||
+      this.winner !== null ||
+      client.reportedWinner !== null
+    ) {
+      return;
+    }
+    client.reportedWinner = clientMsg.winner;
+
+    // Add client vote
+    const winnerKey = JSON.stringify(clientMsg.winner);
+    if (!this.winnerVotes.has(winnerKey)) {
+      this.winnerVotes.set(winnerKey, { ips: new Set(), winner: clientMsg });
+    }
+    const potentialWinner = this.winnerVotes.get(winnerKey)!;
+    potentialWinner.ips.add(client.ip);
+
+    const activeUniqueIPs = new Set(this.activeClients.map((c) => c.ip));
+
+    const ratio = `${potentialWinner.ips.size}/${activeUniqueIPs.size}`;
+    this.log.info(
+      `recieved winner vote ${clientMsg.winner}, ${ratio} votes for this winner`,
+      {
+        clientID: client.clientID,
+      },
+    );
+
+    if (potentialWinner.ips.size * 2 < activeUniqueIPs.size) {
+      return;
+    }
+
+    // Vote succeeded
+    this.winner = potentialWinner.winner;
+    this.log.info(
+      `Winner determined by ${potentialWinner.ips.size}/${activeUniqueIPs.size} active IPs`,
+      {
+        winnerKey: winnerKey,
+      },
+    );
+    this.archiveGame();
+  }
 }