auto-git:

[add] src/serialization/editor-autosave.ts

src/serialization/editor-autosave.ts

@@ -0,0 +1,128 @@
+import type { SaveSceneDocumentDraftResult } from "./local-draft-storage";
+
+export type EditorAutosaveScope = "document" | "viewport" | "all";
+
+export interface EditorAutosaveRequest {
+  document: boolean;
+  viewportLayout: boolean;
+}
+
+export interface EditorAutosaveControllerOptions {
+  debounceMs?: number;
+  onComplete?: (result: SaveSceneDocumentDraftResult) => void;
+  saveDraft: (
+    request: EditorAutosaveRequest
+  ) => Promise<SaveSceneDocumentDraftResult> | SaveSceneDocumentDraftResult;
+}
+
+const UP_TO_DATE_RESULT: SaveSceneDocumentDraftResult = {
+  status: "saved",
+  message: "Autosave is already up to date."
+};
+
+function createEmptyRequest(): EditorAutosaveRequest {
+  return {
+    document: false,
+    viewportLayout: false
+  };
+}
+
+function hasPendingWork(request: EditorAutosaveRequest): boolean {
+  return request.document || request.viewportLayout;
+}
+
+function mergeScopeIntoRequest(
+  request: EditorAutosaveRequest,
+  scope: EditorAutosaveScope
+) {
+  if (scope === "document" || scope === "all") {
+    request.document = true;
+  }
+
+  if (scope === "viewport" || scope === "all") {
+    request.viewportLayout = true;
+  }
+}
+
+export class EditorAutosaveController {
+  private readonly debounceMs: number;
+  private readonly onComplete:
+    | ((result: SaveSceneDocumentDraftResult) => void)
+    | undefined;
+  private readonly saveDraft: (
+    request: EditorAutosaveRequest
+  ) => Promise<SaveSceneDocumentDraftResult> | SaveSceneDocumentDraftResult;
+  private timeoutId: number | null = null;
+  private pendingRequest = createEmptyRequest();
+  private inFlight = false;
+  private drainPromise: Promise<SaveSceneDocumentDraftResult> | null = null;
+
+  constructor(options: EditorAutosaveControllerOptions) {
+    this.debounceMs = options.debounceMs ?? 200;
+    this.onComplete = options.onComplete;
+    this.saveDraft = options.saveDraft;
+  }
+
+  schedule(scope: EditorAutosaveScope = "all") {
+    mergeScopeIntoRequest(this.pendingRequest, scope);
+    this.clearPendingTimeout();
+    this.timeoutId = window.setTimeout(() => {
+      this.timeoutId = null;
+      void this.drain();
+    }, this.debounceMs);
+  }
+
+  flush(scope?: EditorAutosaveScope): Promise<SaveSceneDocumentDraftResult> {
+    if (scope !== undefined) {
+      mergeScopeIntoRequest(this.pendingRequest, scope);
+    }
+
+    this.clearPendingTimeout();
+    return this.drain();
+  }
+
+  dispose() {
+    this.clearPendingTimeout();
+  }
+
+  private clearPendingTimeout() {
+    if (this.timeoutId === null) {
+      return;
+    }
+
+    window.clearTimeout(this.timeoutId);
+    this.timeoutId = null;
+  }
+
+  private drain(): Promise<SaveSceneDocumentDraftResult> {
+    if (this.inFlight) {
+      return this.drainPromise ?? Promise.resolve(UP_TO_DATE_RESULT);
+    }
+
+    this.drainPromise = this.runPendingSaves();
+    return this.drainPromise;
+  }
+
+  private async runPendingSaves(): Promise<SaveSceneDocumentDraftResult> {
+    this.inFlight = true;
+    let lastResult = UP_TO_DATE_RESULT;
+
+    try {
+      while (hasPendingWork(this.pendingRequest)) {
+        const request = this.pendingRequest;
+        this.pendingRequest = createEmptyRequest();
+        lastResult = await this.saveDraft({ ...request });
+        this.onComplete?.(lastResult);
+      }
+
+      return lastResult;
+    } finally {
+      this.inFlight = false;
+      this.drainPromise = null;
+
+      if (hasPendingWork(this.pendingRequest)) {
+        void this.drain();
+      }
+    }
+  }
+}