From abf334607e17885ff0a7a28a0bf3a27068a82035 Mon Sep 17 00:00:00 2001
From: Juan Sebastian Montoya <juansmm@outlook.com>
Date: Sat, 14 Sep 2024 23:51:24 -0500
Subject: [PATCH] feat(#10): reset camera position after changing level

---
 index.js                               |  1 +
 modules/event-emitter.js               | 32 ++++++++++++++++++++++++++
 modules/game-objects/camera.js         |  5 ++++
 modules/game-objects/game-object.js    |  3 +++
 modules/game-objects/map-management.js |  1 +
 modules/game-objects/map.js            |  7 ++++--
 6 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 modules/event-emitter.js

diff --git a/index.js b/index.js
index 756299c..f392821 100644
--- a/index.js
+++ b/index.js
@@ -26,6 +26,7 @@ const foregroundMaps = [
     layer: 1,
     selected: true,
   },
+  { name: "ocean", imageId: "overworld", elementId: "level2", layer: 2 },
 ];
 
 const clicableObjects = ["debug", "level1", "level2"];
diff --git a/modules/event-emitter.js b/modules/event-emitter.js
new file mode 100644
index 0000000..1795c1a
--- /dev/null
+++ b/modules/event-emitter.js
@@ -0,0 +1,32 @@
+class EventEmitterSingleton {
+  static instance;
+  eventEmitter;
+
+  constructor() {
+    this.eventEmitter = {};
+  }
+
+  static getInstance() {
+    if (!EventEmitterSingleton.instance) {
+      EventEmitterSingleton.instance = new EventEmitterSingleton();
+    }
+    return EventEmitterSingleton.instance;
+  }
+
+  on(eventName, callback) {
+    if (!this.eventEmitter[eventName]) {
+      this.eventEmitter[eventName] = [];
+    }
+    this.eventEmitter[eventName].push(callback);
+  }
+
+  emit(eventName, ...args) {
+    if (this.eventEmitter[eventName]) {
+      this.eventEmitter[eventName].forEach((callback) => {
+        callback(...args);
+      });
+    }
+  }
+}
+
+export const eventEmitter = EventEmitterSingleton.getInstance();
diff --git a/modules/game-objects/camera.js b/modules/game-objects/camera.js
index 5e24e70..75b316d 100644
--- a/modules/game-objects/camera.js
+++ b/modules/game-objects/camera.js
@@ -27,6 +27,11 @@ export class Camera extends GameObject {
       (acc, item) => ({ ...acc, [item.key]: item }),
       {}
     );
+    this.eventEmitter.on("changeLevel", () => {
+      this.x = x;
+      this.y = y;
+      this.moveCamera(0, 0, 0);
+    });
   }
 
   update(delta) {
diff --git a/modules/game-objects/game-object.js b/modules/game-objects/game-object.js
index 932f923..609726b 100644
--- a/modules/game-objects/game-object.js
+++ b/modules/game-objects/game-object.js
@@ -1,3 +1,5 @@
+import { eventEmitter } from "../event-emitter.js";
+
 export class GameObject {
   constructor(options = {}) {
     const {
@@ -14,6 +16,7 @@ export class GameObject {
     this.height = height;
     this.gameObjects = gameObjects;
     this.debug = debug;
+    this.eventEmitter = eventEmitter;
   }
 
   async load() {
diff --git a/modules/game-objects/map-management.js b/modules/game-objects/map-management.js
index fd4c952..163f280 100644
--- a/modules/game-objects/map-management.js
+++ b/modules/game-objects/map-management.js
@@ -28,5 +28,6 @@ export class MapManagement extends GameObject {
     }
     const map = this.gameObjects.find((item) => item.elementId === elementId);
     this.selected = map.name;
+    this.eventEmitter.emit("changeLevel");
   }
 }
diff --git a/modules/game-objects/map.js b/modules/game-objects/map.js
index 70f0933..153b883 100644
--- a/modules/game-objects/map.js
+++ b/modules/game-objects/map.js
@@ -29,7 +29,7 @@ export class Map extends GameObject {
     });
     this.levelConfig = await response.json();
     const layer = this.levelConfig.layers[this.layer];
-    const { data, height, width } = layer;
+    const { data, height, width } = layer ?? {};
     this.width = width;
     this.height = height;
     this.data = data;
@@ -39,6 +39,9 @@ export class Map extends GameObject {
     if (this._level) {
       return this._level;
     }
+    if (!this.width || !this.height) {
+      return null;
+    }
     const { ctx, canvas } = createCanvas(
       this.width * TILE_SIZE,
       this.height * TILE_SIZE
@@ -84,7 +87,7 @@ export class Map extends GameObject {
   }
 
   render(ctx, sourceX, sourceY, width, height) {
-    if (!this.levelConfig || !this.selected) {
+    if (!this.levelConfig || !this.selected || !this.level) {
       return;
     }