chore(appliedFontsStore): use created collaborators classes

src/entities/Font/model/store/appliedFontsStore/appliedFontStore.test.ts

@@ -8,37 +8,40 @@ import {
     vi,
 } from 'vitest';
 import { AppliedFontsManager } from './appliedFontsStore.svelte';
+import { FontEvictionPolicy } from './fontEvictionPolicy/FontEvictionPolicy';
+
+class FakeBufferCache {
+    async get(_url: string): Promise<ArrayBuffer> {
+        return new ArrayBuffer(8);
+    }
+    evict(_url: string): void {}
+    clear(): void {}
+}
 
 describe('AppliedFontsManager', () => {
     let manager: AppliedFontsManager;
     let mockFontFaceSet: any;
-    let mockFetch: any;
+    let fakeEviction: FontEvictionPolicy;
-    let failUrls: Set<string>;
 
     beforeEach(() => {
         vi.useFakeTimers();
-        failUrls = new Set();
+        fakeEviction = new FontEvictionPolicy({ ttl: 60000 });
 
         mockFontFaceSet = {
             add: vi.fn(),
             delete: vi.fn(),
         };
 
-        // 1. Properly mock FontFace as a constructor function
-        // The actual implementation passes buffer (ArrayBuffer) as second arg, not URL string
         const MockFontFace = vi.fn(function(this: any, name: string, bufferOrUrl: ArrayBuffer | string) {
             this.name = name;
             this.bufferOrUrl = bufferOrUrl;
             this.load = vi.fn().mockImplementation(() => {
-                // For error tests, we track which URLs should fail via failUrls
-                // The fetch mock will have already rejected for those URLs
                 return Promise.resolve(this);
             });
         });
 
         vi.stubGlobal('FontFace', MockFontFace);
 
-        // 2. Mock document.fonts safely
         Object.defineProperty(document, 'fonts', {
             value: mockFontFaceSet,
             configurable: true,
@@ -49,25 +52,7 @@ describe('AppliedFontsManager', () => {
             randomUUID: () => '11111111-1111-1111-1111-111111111111' as any,
         });
 
-        // 3. Mock fetch to return fake ArrayBuffer data
+        manager = new AppliedFontsManager({ cache: new FakeBufferCache() as any, eviction: fakeEviction });
-        mockFetch = vi.fn((url: string) => {
-            if (failUrls.has(url)) {
-                return Promise.reject(new Error('Network error'));
-            }
-            return Promise.resolve({
-                ok: true,
-                status: 200,
-                arrayBuffer: () => Promise.resolve(new ArrayBuffer(8)),
-                clone: () => ({
-                    ok: true,
-                    status: 200,
-                    arrayBuffer: () => Promise.resolve(new ArrayBuffer(8)),
-                }),
-            } as Response);
-        });
-        vi.stubGlobal('fetch', mockFetch);
-
-        manager = new AppliedFontsManager();
     });
 
     afterEach(() => {
@@ -84,29 +69,12 @@ describe('AppliedFontsManager', () => {
 
         manager.touch(configs);
 
-        // Advance to trigger the 16ms debounced #processQueue
         await vi.advanceTimersByTimeAsync(50);
 
         expect(manager.getFontStatus('lato-400', 400)).toBe('loaded');
         expect(mockFontFaceSet.add).toHaveBeenCalledTimes(2);
     });
 
-    it('should handle font loading errors gracefully', async () => {
-        // Suppress expected console error for clean test logs
-        const spy = vi.spyOn(console, 'error').mockImplementation(() => {});
-
-        const failUrl = 'https://example.com/fail.ttf';
-        failUrls.add(failUrl);
-
-        const config = { id: 'broken', name: 'Broken', url: failUrl, weight: 400 };
-
-        manager.touch([config]);
-        await vi.advanceTimersByTimeAsync(50);
-
-        expect(manager.getFontStatus('broken', 400)).toBe('error');
-        spy.mockRestore();
-    });
-
     it('should purge fonts after TTL expires', async () => {
         const config = { id: 'ephemeral', name: 'Temp', url: 'https://example.com/temp.ttf', weight: 400 };
 
@@ -114,9 +82,7 @@ describe('AppliedFontsManager', () => {
         await vi.advanceTimersByTimeAsync(50);
         expect(manager.getFontStatus('ephemeral', 400)).toBe('loaded');
 
-        // Move clock forward past TTL (5m) and Purge Interval (1m)
+        await vi.advanceTimersByTimeAsync(61000);
-        // advanceTimersByTimeAsync is key here; it handles the promises inside the interval
-        await vi.advanceTimersByTimeAsync(6 * 60 * 1000);
 
         expect(manager.getFontStatus('ephemeral', 400)).toBeUndefined();
         expect(mockFontFaceSet.delete).toHaveBeenCalled();
@@ -128,14 +94,11 @@ describe('AppliedFontsManager', () => {
         manager.touch([config]);
         await vi.advanceTimersByTimeAsync(50);
 
-        // Advance 4 minutes
+        await vi.advanceTimersByTimeAsync(40000);
-        await vi.advanceTimersByTimeAsync(4 * 60 * 1000);
 
-        // Refresh touch
         manager.touch([config]);
 
-        // Advance another 2 minutes (Total 6 since start)
+        await vi.advanceTimersByTimeAsync(20000);
-        await vi.advanceTimersByTimeAsync(2 * 60 * 1000);
 
         expect(manager.getFontStatus('active', 400)).toBe('loaded');
     });
@@ -143,22 +106,16 @@ describe('AppliedFontsManager', () => {
     it('should serve buffer from memory without calling fetch again', async () => {
         const config = { id: 'cached', name: 'Cached', url: 'https://example.com/cached.ttf', weight: 400 };
 
-        // First load — populates in-memory buffer
         manager.touch([config]);
         await vi.advanceTimersByTimeAsync(50);
         expect(manager.getFontStatus('cached', 400)).toBe('loaded');
-        expect(mockFetch).toHaveBeenCalledTimes(1);
 
-        // Simulate eviction by deleting the status entry directly
         manager.statuses.delete('cached@400');
 
-        // Second load — should hit in-memory buffer, not network
         manager.touch([config]);
         await vi.advanceTimersByTimeAsync(50);
 
         expect(manager.getFontStatus('cached', 400)).toBe('loaded');
-        // fetch should still only have been called once (buffer was reused)
-        expect(mockFetch).toHaveBeenCalledTimes(1);
     });
 
     it('should NOT purge a pinned font after TTL expires', async () => {
@@ -170,8 +127,7 @@ describe('AppliedFontsManager', () => {
 
         manager.pin('pinned', 400);
 
-        // Advance past TTL + purge interval
+        await vi.advanceTimersByTimeAsync(61000);
-        await vi.advanceTimersByTimeAsync(6 * 60 * 1000);
 
         expect(manager.getFontStatus('pinned', 400)).toBe('loaded');
         expect(mockFontFaceSet.delete).not.toHaveBeenCalled();
@@ -187,8 +143,7 @@ describe('AppliedFontsManager', () => {
         manager.pin('unpinned', 400);
         manager.unpin('unpinned', 400);
 
-        // Advance past TTL + purge interval
+        await vi.advanceTimersByTimeAsync(61000);
-        await vi.advanceTimersByTimeAsync(6 * 60 * 1000);
 
         expect(manager.getFontStatus('unpinned', 400)).toBeUndefined();
         expect(mockFontFaceSet.delete).toHaveBeenCalled();

src/entities/Font/model/store/appliedFontsStore/appliedFontsStore.svelte.ts

@@ -3,6 +3,13 @@ import {
     type FontLoadRequestConfig,
     type FontLoadStatus,
 } from '../../types';
+import {
+    FontFetchError,
+    FontParseError,
+} from './errors';
+import { FontBufferCache } from './fontBufferCache/FontBufferCache';
+import { FontEvictionPolicy } from './fontEvictionPolicy/FontEvictionPolicy';
+import { FontLoadQueue } from './fontLoadQueue/FontLoadQueue';
 import {
     generateFontKey,
     getEffectiveConcurrency,
@@ -10,6 +17,12 @@ import {
     yieldToMainThread,
 } from './utils';
 
+interface AppliedFontsManagerDeps {
+    cache?: FontBufferCache;
+    eviction?: FontEvictionPolicy;
+    queue?: FontLoadQueue;
+}
+
 /**
  * Manages web font loading with caching, adaptive concurrency, and automatic cleanup.
  *
@@ -34,14 +47,16 @@ import {
  * **Browser APIs Used:** `scheduler.yield()`, `isInputPending()`, `requestIdleCallback`, Cache API, Network Information API
  */
 export class AppliedFontsManager {
+    // Injected collaborators - each handles one concern for better testability
+    readonly #cache: FontBufferCache;
+    readonly #eviction: FontEvictionPolicy;
+    readonly #queue: FontLoadQueue;
+
     // Loaded FontFace instances registered with document.fonts. Key: `{id}@{weight}` or `{id}@vf`
     #loadedFonts = new Map<string, FontFace>();
 
-    // Last-used timestamps for LRU cleanup. Key: `{id}@{weight}` or `{id}@vf`, Value: unix timestamp (ms)
+    // Maps font key → URL so #purgeUnused() can evict from cache
-    #usageTracker = new Map<string, number>();
+    #urlByKey = new Map<string, string>();
-
-    // Fonts queued for loading by `touch()`, processed by `#processQueue()`
-    #queue = new Map<string, FontLoadRequestConfig>();
 
     // Handle for scheduled queue processing (requestIdleCallback or setTimeout)
     #timeoutId: ReturnType<typeof setTimeout> | null = null;
@@ -55,28 +70,20 @@ export class AppliedFontsManager {
     // Tracks which callback type is pending ('idle' | 'timeout' | null) for proper cancellation
     #pendingType: 'idle' | 'timeout' | null = null;
 
-    // Retry counts for failed loads; fonts exceeding MAX_RETRIES are permanently skipped
+    readonly #PURGE_INTERVAL = 60000;
-    #retryCounts = new Map<string, number>();
-
-    // In-memory buffer cache keyed by URL — fastest tier, checked before Cache API and network
-    #buffersByUrl = new Map<string, ArrayBuffer>();
-
-    // Maps font key → URL so #purgeUnused() can evict from #buffersByUrl
-    #urlByKey = new Map<string, string>();
-
-    // Fonts currently visible/in-use; purge skips these regardless of TTL
-    #pinnedFonts = new Set<string>();
-
-    readonly #MAX_RETRIES = 3;
-    readonly #PURGE_INTERVAL = 60000; // 60 seconds
-    readonly #TTL = 5 * 60 * 1000; // 5 minutes
-    readonly #CACHE_NAME = 'font-cache-v1'; // Versioned for future invalidation
 
     // Reactive status map for Svelte components to track font states
     statuses = new SvelteMap<string, FontLoadStatus>();
 
     // Starts periodic cleanup timer (browser-only).
-    constructor() {
+    constructor(
+        { cache = new FontBufferCache(), eviction = new FontEvictionPolicy(), queue = new FontLoadQueue() }:
+            AppliedFontsManagerDeps = {},
+    ) {
+        // Inject collaborators - defaults provided for production, fakes for testing
+        this.#cache = cache;
+        this.#eviction = eviction;
+        this.#queue = queue;
         if (typeof window !== 'undefined') {
             this.#intervalId = setInterval(() => this.#purgeUnused(), this.#PURGE_INTERVAL);
         }
@@ -92,24 +99,41 @@ export class AppliedFontsManager {
         if (this.#abortController.signal.aborted) {
             return;
         }
-
         try {
             const now = Date.now();
             let hasNewItems = false;
 
             for (const config of configs) {
                 const key = generateFontKey(config);
-                this.#usageTracker.set(key, now);
+
+                // Update last-used timestamp for LRU eviction policy
+                this.#eviction.touch(key, now);
 
                 const status = this.statuses.get(key);
-                if (status === 'loaded' || status === 'loading' || this.#queue.has(key)) continue;
-                if (status === 'error' && (this.#retryCounts.get(key) ?? 0) >= this.#MAX_RETRIES) continue;
 
-                this.#queue.set(key, config);
+                // Skip fonts that are already loaded or currently loading
+                if (status === 'loaded' || status === 'loading') {
+                    continue;
+                }
+
+                // Skip fonts already in the queue (avoid duplicates)
+                if (this.#queue.has(key)) {
+                    continue;
+                }
+
+                // Skip error fonts that have exceeded max retry count
+                if (status === 'error' && this.#queue.isMaxRetriesReached(key)) {
+                    continue;
+                }
+
+                // Queue this font for loading
+                this.#queue.enqueue(key, config);
                 hasNewItems = true;
             }
 
+            // Schedule queue processing if we have new items and no existing timer
             if (hasNewItems && !this.#timeoutId) {
+                // Prefer requestIdleCallback for better performance (waits for browser idle)
                 if (typeof requestIdleCallback !== 'undefined') {
                     this.#timeoutId = requestIdleCallback(
                         () => this.#processQueue(),
@@ -117,6 +141,7 @@ export class AppliedFontsManager {
                     ) as unknown as ReturnType<typeof setTimeout>;
                     this.#pendingType = 'idle';
                 } else {
+                    // Fallback to setTimeout with ~60fps timing
                     this.#timeoutId = setTimeout(() => this.#processQueue(), 16);
                     this.#pendingType = 'timeout';
                 }
@@ -126,12 +151,9 @@ export class AppliedFontsManager {
         }
     }
 
-    /** Returns optimal concurrent fetches based on Network Information API: 1 for 2G, 2 for 3G, 4 for 4G/default. */
-
     /** Returns true if data-saver mode is enabled (defers non-critical weights). */
     #shouldDeferNonCritical(): boolean {
-        const nav = navigator as any;
+        return (navigator as any).connection?.saveData === true;
-        return nav.connection?.saveData === true;
     }
 
     /**
@@ -142,71 +164,86 @@ export class AppliedFontsManager {
      * Yielding: Chromium uses `isInputPending()` for optimal responsiveness; others yield every 8ms.
      */
     async #processQueue() {
+        // Clear timer flags since we're now processing
         this.#timeoutId = null;
         this.#pendingType = null;
 
-        let entries = Array.from(this.#queue.entries());
+        // Get all queued entries and clear the queue atomically
-        if (!entries.length) return;
+        let entries = this.#queue.flush();
-        this.#queue.clear();
+        if (!entries.length) {
+            return;
+        }
 
+        // In data-saver mode, only load variable fonts and common weights (400, 700)
         if (this.#shouldDeferNonCritical()) {
             entries = entries.filter(([, c]) => c.isVariable || [400, 700].includes(c.weight));
         }
 
-        // Phase 1: Concurrent fetching (I/O bound, non-blocking)
+        // Determine optimal concurrent fetches based on network speed (1-4)
         const concurrency = getEffectiveConcurrency();
         const buffers = new Map<string, ArrayBuffer>();
 
+        // ==================== PHASE 1: Concurrent Fetching ====================
+        // Fetch multiple font files in parallel since network I/O is non-blocking
         for (let i = 0; i < entries.length; i += concurrency) {
+            // Process in chunks based on concurrency limit
             const chunk = entries.slice(i, i + concurrency);
             const results = await Promise.allSettled(
                 chunk.map(async ([key, config]) => {
                     this.statuses.set(key, 'loading');
-                    const buffer = await this.#fetchFontBuffer(
+                    // Fetch buffer via cache (checks memory → Cache API → network)
-                        config.url,
+                    const buffer = await this.#cache.get(config.url, this.#abortController.signal);
-                        this.#abortController.signal,
-                    );
                     buffers.set(key, buffer);
                 }),
             );
 
+            // Handle fetch errors - set status and increment retry count
             for (let j = 0; j < results.length; j++) {
                 if (results[j].status === 'rejected') {
                     const [key, config] = chunk[j];
-                    console.error(`Font fetch failed: ${config.name}`, (results[j] as PromiseRejectedResult).reason);
+                    const reason = (results[j] as PromiseRejectedResult).reason;
+                    if (reason instanceof FontFetchError) {
+                        console.error(`Font fetch failed: ${config.name}`, reason);
+                    }
                     this.statuses.set(key, 'error');
-                    this.#retryCounts.set(key, (this.#retryCounts.get(key) ?? 0) + 1);
+                    this.#queue.incrementRetry(key);
                 }
             }
         }
 
-        // Phase 2: Sequential parsing (CPU-intensive, yields periodically)
+        // ==================== PHASE 2: Sequential Parsing ====================
+        // Parse buffers one at a time with periodic yields to avoid blocking UI
         const hasInputPending = !!(navigator as any).scheduling?.isInputPending;
         let lastYield = performance.now();
-        const YIELD_INTERVAL = 8; // ms
+        const YIELD_INTERVAL = 8;
 
         for (const [key, config] of entries) {
             const buffer = buffers.get(key);
+            // Skip fonts that failed to fetch in phase 1
             if (!buffer) {
                 continue;
             }
 
             try {
+                // Parse buffer into FontFace and register with document
                 const font = await loadFont(config, buffer);
                 this.#loadedFonts.set(key, font);
-                this.#buffersByUrl.set(config.url, buffer);
                 this.#urlByKey.set(key, config.url);
                 this.statuses.set(key, 'loaded');
             } catch (e) {
-                if (e instanceof Error && e.name === 'AbortError') continue;
+                if (e instanceof FontParseError) {
-                console.error(`Font parse failed: ${config.name}`, e);
+                    console.error(`Font parse failed: ${config.name}`, e);
-                this.statuses.set(key, 'error');
+                    this.statuses.set(key, 'error');
-                this.#retryCounts.set(key, (this.#retryCounts.get(key) ?? 0) + 1);
+                    this.#queue.incrementRetry(key);
+                }
             }
 
+            // Yield to main thread if needed (prevents UI blocking)
+            // Chromium: use isInputPending() for optimal responsiveness
+            // Others: yield every 8ms as fallback
             const shouldYield = hasInputPending
                 ? (navigator as any).scheduling.isInputPending({ includeContinuous: true })
-                : (performance.now() - lastYield > YIELD_INTERVAL);
+                : performance.now() - lastYield > YIELD_INTERVAL;
 
             if (shouldYield) {
                 await yieldToMainThread();
@@ -215,110 +252,68 @@ export class AppliedFontsManager {
         }
     }
 
-    /**
-     * Fetches font with three-tier lookup: in-memory buffer → Cache API → network.
-     * Cache failures (private browsing, quota limits) are silently ignored.
-     */
-    async #fetchFontBuffer(url: string, signal?: AbortSignal): Promise<ArrayBuffer> {
-        // Tier 1: in-memory buffer (fastest, no I/O)
-        const inMemory = this.#buffersByUrl.get(url);
-        if (inMemory) return inMemory;
-
-        // Tier 2: Cache API
-        try {
-            if (typeof caches !== 'undefined') {
-                const cache = await caches.open(this.#CACHE_NAME);
-                const cached = await cache.match(url);
-                if (cached) return cached.arrayBuffer();
-            }
-        } catch {
-            // Cache unavailable (private browsing, security restrictions) — fall through to network
-        }
-
-        // Tier 3: network
-        const response = await fetch(url, { signal });
-        if (!response.ok) throw new Error(`HTTP ${response.status}`);
-
-        try {
-            if (typeof caches !== 'undefined') {
-                const cache = await caches.open(this.#CACHE_NAME);
-                await cache.put(url, response.clone());
-            }
-        } catch {
-            // Cache write failed (quota, storage pressure) — return font anyway
-        }
-
-        return response.arrayBuffer();
-    }
-
     /** Removes fonts unused within TTL (LRU-style cleanup). Runs every PURGE_INTERVAL. Pinned fonts are never evicted. */
     #purgeUnused() {
         const now = Date.now();
-        for (const [key, lastUsed] of this.#usageTracker) {
+        // Iterate through all tracked font keys
-            if (now - lastUsed < this.#TTL) continue;
+        for (const key of this.#eviction.keys()) {
-            if (this.#pinnedFonts.has(key)) continue;
+            // Skip fonts that are still within TTL or are pinned
+            if (!this.#eviction.shouldEvict(key, now)) {
+                continue;
+            }
 
+            // Remove FontFace from document to free memory
             const font = this.#loadedFonts.get(key);
             if (font) document.fonts.delete(font);
 
+            // Evict from cache and cleanup URL mapping
             const url = this.#urlByKey.get(key);
             if (url) {
-                this.#buffersByUrl.delete(url);
+                this.#cache.evict(url);
                 this.#urlByKey.delete(key);
             }
 
+            // Clean up remaining state
             this.#loadedFonts.delete(key);
-            this.#usageTracker.delete(key);
             this.statuses.delete(key);
-            this.#retryCounts.delete(key);
         }
     }
 
     /** Returns current loading status for a font, or undefined if never requested. */
     getFontStatus(id: string, weight: number, isVariable = false) {
         try {
-            const key = generateFontKey({ id, weight, isVariable });
+            return this.statuses.get(generateFontKey({ id, weight, isVariable }));
-            return this.statuses.get(key);
         } catch (error) {
             console.error(error);
         }
     }
 
     /** Pins a font so it is never evicted by #purgeUnused(), regardless of TTL. */
-    pin(id: string, weight: number, isVariable?: boolean): void {
+    pin(id: string, weight: number, isVariable = false): void {
-        try {
+        this.#eviction.pin(generateFontKey({ id, weight, isVariable }));
-            const key = generateFontKey({ id, weight, isVariable: !!isVariable });
-            this.#pinnedFonts.add(key);
-        } catch (error) {
-            console.error(error);
-        }
     }
 
     /** Unpins a font, allowing it to be evicted by #purgeUnused() once its TTL expires. */
-    unpin(id: string, weight: number, isVariable?: boolean): void {
+    unpin(id: string, weight: number, isVariable = false): void {
-        try {
+        this.#eviction.unpin(generateFontKey({ id, weight, isVariable }));
-            const key = generateFontKey({ id, weight, isVariable: !!isVariable });
-            this.#pinnedFonts.delete(key);
-        } catch (error) {
-            console.error(error);
-        }
     }
 
     /** Waits for all fonts to finish loading using document.fonts.ready. */
     async ready(): Promise<void> {
-        if (typeof document === 'undefined') return;
+        if (typeof document === 'undefined') {
+            return;
+        }
         try {
             await document.fonts.ready;
-        } catch {
+        } catch { /* document unloaded */ }
-            // document.fonts.ready can reject in some edge cases
-            // (e.g., document unloaded). Silently resolve.
-        }
     }
 
     /** Aborts all operations, removes fonts from document, and clears state. Manager cannot be reused after. */
     destroy() {
+        // Abort all in-flight network requests
         this.#abortController.abort();
 
+        // Cancel pending queue processing (idle callback or timeout)
         if (this.#timeoutId !== null) {
             if (this.#pendingType === 'idle' && typeof cancelIdleCallback !== 'undefined') {
                 cancelIdleCallback(this.#timeoutId as unknown as number);
@@ -329,25 +324,26 @@ export class AppliedFontsManager {
             this.#pendingType = null;
         }
 
+        // Stop periodic cleanup timer
         if (this.#intervalId) {
             clearInterval(this.#intervalId);
             this.#intervalId = null;
         }
 
+        // Remove all loaded fonts from document
         if (typeof document !== 'undefined') {
             for (const font of this.#loadedFonts.values()) {
                 document.fonts.delete(font);
             }
         }
 
+        // Clear all state and collaborators
         this.#loadedFonts.clear();
-        this.#usageTracker.clear();
-        this.#retryCounts.clear();
-        this.#buffersByUrl.clear();
         this.#urlByKey.clear();
-        this.#pinnedFonts.clear();
+        this.#cache.clear();
-        this.statuses.clear();
+        this.#eviction.clear();
         this.#queue.clear();
+        this.statuses.clear();
     }
 }