first commit

js/managers/ResourceManager.js

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+/**
+ * ResourceManager.js
+ * Handles preloading of image resources using wx.createImage.
+ * Provides progress callback and cached access to loaded images.
+ */
+
+class ResourceManager {
+  constructor() {
+    /** @type {Map<string, Image>} */
+    this._cache = new Map();
+    this._totalAssets = 0;
+    this._loadedAssets = 0;
+  }
+
+  /**
+   * Preload a list of image assets.
+   * @param {Array<{key: string, src: string}>} assetList - Assets to load.
+   * @param {Function} [onProgress] - Called with (loaded, total) on each load.
+   * @returns {Promise<void>} Resolves when all assets are loaded.
+   */
+  loadImages(assetList, onProgress) {
+    this._totalAssets = assetList.length;
+    this._loadedAssets = 0;
+
+    if (this._totalAssets === 0) {
+      return Promise.resolve();
+    }
+
+    const promises = assetList.map(({ key, src }) => {
+      return new Promise((resolve, reject) => {
+        // If already cached, skip
+        if (this._cache.has(key)) {
+          this._loadedAssets++;
+          if (onProgress) onProgress(this._loadedAssets, this._totalAssets);
+          resolve();
+          return;
+        }
+
+        const img = wx.createImage();
+        img.onload = () => {
+          this._cache.set(key, img);
+          this._loadedAssets++;
+          if (onProgress) onProgress(this._loadedAssets, this._totalAssets);
+          resolve();
+        };
+        img.onerror = (err) => {
+          console.warn(`[ResourceManager] Failed to load: ${src}`, err);
+          // Resolve anyway so other assets continue loading
+          this._loadedAssets++;
+          if (onProgress) onProgress(this._loadedAssets, this._totalAssets);
+          resolve();
+        };
+        img.src = src;
+      });
+    });
+
+    return Promise.all(promises).then(() => {});
+  }
+
+  /**
+   * Get a loaded image by key.
+   * @param {string} key
+   * @returns {Image|null}
+   */
+  getImage(key) {
+    return this._cache.get(key) || null;
+  }
+
+  /**
+   * Check if an image is loaded.
+   * @param {string} key
+   * @returns {boolean}
+   */
+  hasImage(key) {
+    return this._cache.has(key);
+  }
+
+  /**
+   * Clear all cached images.
+   */
+  clear() {
+    this._cache.clear();
+    this._totalAssets = 0;
+    this._loadedAssets = 0;
+  }
+
+  /** Current loading progress (0 to 1). */
+  get progress() {
+    if (this._totalAssets === 0) return 1;
+    return this._loadedAssets / this._totalAssets;
+  }
+}
+
+module.exports = ResourceManager;