Adding variables (on the front side for now)

front/src/Phaser/Game/SharedVariablesManager.ts

@@ -0,0 +1,59 @@
+/**
+ * Handles variables shared between the scripting API and the server.
+ */
+import type {RoomConnection} from "../../Connexion/RoomConnection";
+import {iframeListener} from "../../Api/IframeListener";
+import type {Subscription} from "rxjs";
+import type {GameMap} from "./GameMap";
+import type {ITiledMapObject} from "../Map/ITiledMap";
+
+export class SharedVariablesManager {
+    private _variables = new Map<string, unknown>();
+    private iframeListenerSubscription: Subscription;
+    private variableObjects: Map<string, ITiledMapObject>;
+
+    constructor(private roomConnection: RoomConnection, private gameMap: GameMap) {
+        // We initialize the list of variable object at room start. The objects cannot be edited later
+        // (otherwise, this would cause a security issue if the scripting API can edit this list of objects)
+        this.variableObjects = SharedVariablesManager.findVariablesInMap(gameMap);
+
+        // When a variable is modified from an iFrame
+        this.iframeListenerSubscription = iframeListener.setVariableStream.subscribe((event) => {
+            const key = event.key;
+
+            if (!this.variableObjects.has(key)) {
+                const errMsg = 'A script is trying to modify variable "'+key+'" but this variable is not defined in the map.' +
+                    'There should be an object in the map whose name is "'+key+'" and whose type is "variable"';
+                console.error(errMsg);
+                throw new Error(errMsg);
+            }
+
+            this._variables.set(key, event.value);
+            // TODO: dispatch to the room connection.
+        });
+    }
+
+    private static findVariablesInMap(gameMap: GameMap): Map<string, ITiledMapObject> {
+        const objects = new Map<string, ITiledMapObject>();
+        for (const layer of gameMap.getMap().layers) {
+            if (layer.type === 'objectgroup') {
+                for (const object of layer.objects) {
+                    if (object.type === 'variable') {
+                        // We store a copy of the object (to make it immutable)
+                        objects.set(object.name, {...object});
+                    }
+                }
+            }
+        }
+        return objects;
+    }
+
+
+    public close(): void {
+        this.iframeListenerSubscription.unsubscribe();
+    }
+
+    get variables(): Map<string, unknown> {
+        return this._variables;
+    }
+}