Add auto-upgrade buildings feature with middle mouse click (#1597)

## Description:

This PR implements a new feature allowing automatic upgrade of the
nearest building using the middle mouse button. This feature greatly
simplifies the upgrade process that previously required a right-click +
building recreation.

## 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 have read and accepted the CLA agreement (only required once).

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

Kipstzz

---------

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>

src/client/ClientGameRunner.ts

@@ -26,6 +26,7 @@ import { loadTerrainMap, TerrainMapData } from "../core/game/TerrainMapLoader";
 import { UserSettings } from "../core/game/UserSettings";
 import { WorkerClient } from "../core/worker/WorkerClient";
 import {
+  AutoUpgradeEvent,
   DoBoatAttackEvent,
   DoGroundAttackEvent,
   InputHandler,
@@ -40,6 +41,7 @@ import {
   SendBoatAttackIntentEvent,
   SendHashEvent,
   SendSpawnIntentEvent,
+  SendUpgradeStructureIntentEvent,
   Transport,
 } from "./Transport";
 import { createCanvas } from "./Utils";
@@ -248,6 +250,7 @@ export class ClientGameRunner {
     }, 20000);
     this.eventBus.on(MouseUpEvent, this.inputEvent.bind(this));
     this.eventBus.on(MouseMoveEvent, this.onMouseMove.bind(this));
+    this.eventBus.on(AutoUpgradeEvent, this.autoUpgradeEvent.bind(this));
     this.eventBus.on(
       DoBoatAttackEvent,
       this.doBoatAttackUnderCursor.bind(this),
@@ -424,6 +427,76 @@ export class ClientGameRunner {
     });
   }
 
+  private autoUpgradeEvent(event: AutoUpgradeEvent) {
+    if (!this.isActive) {
+      return;
+    }
+
+    const cell = this.renderer.transformHandler.screenToWorldCoordinates(
+      event.x,
+      event.y,
+    );
+    if (!this.gameView.isValidCoord(cell.x, cell.y)) {
+      return;
+    }
+
+    const tile = this.gameView.ref(cell.x, cell.y);
+
+    if (this.myPlayer === null) {
+      const myPlayer = this.gameView.playerByClientID(this.lobby.clientID);
+      if (myPlayer === null) return;
+      this.myPlayer = myPlayer;
+    }
+
+    if (this.gameView.inSpawnPhase()) {
+      return;
+    }
+
+    this.findAndUpgradeNearestBuilding(tile);
+  }
+
+  private findAndUpgradeNearestBuilding(clickedTile: TileRef) {
+    this.myPlayer!.actions(clickedTile).then((actions) => {
+      const upgradeUnits: {
+        unitId: number;
+        unitType: UnitType;
+        distance: number;
+      }[] = [];
+
+      for (const bu of actions.buildableUnits) {
+        if (bu.canUpgrade !== false) {
+          const existingUnit = this.gameView
+            .units()
+            .find((unit) => unit.id() === bu.canUpgrade);
+          if (existingUnit) {
+            const distance = this.gameView.manhattanDist(
+              clickedTile,
+              existingUnit.tile(),
+            );
+
+            upgradeUnits.push({
+              unitId: bu.canUpgrade,
+              unitType: bu.type,
+              distance: distance,
+            });
+          }
+        }
+      }
+
+      if (upgradeUnits.length > 0) {
+        upgradeUnits.sort((a, b) => a.distance - b.distance);
+        const bestUpgrade = upgradeUnits[0];
+
+        this.eventBus.emit(
+          new SendUpgradeStructureIntentEvent(
+            bestUpgrade.unitId,
+            bestUpgrade.unitType,
+          ),
+        );
+      }
+    });
+  }
+
   private doBoatAttackUnderCursor(): void {
     const tile = this.getTileUnderCursor();
     if (tile === null) {