feat(sdk): stage 4 — canUndo/canRedo, removeElement GSAP cascade, override-set cleanup

packages/sdk/src/engine/mutate.gsap.test.ts

@@ -419,3 +419,61 @@ describe("removeLabel", () => {
     expect(result.forward).toHaveLength(0);
   });
 });
+
+// ─── removeElement GSAP cascade ──────────────────────────────────────────────
+
+describe("removeElement — GSAP cascade", () => {
+  it("removes animations targeting the removed element from the script", () => {
+    const parsed = fresh();
+    const result = applyOp(parsed, { type: "removeElement", target: "hf-box" });
+    // forward: [remove_element, replace_script]
+    expect(result.forward).toHaveLength(2);
+    expect(result.forward[0]).toEqual({ op: "remove", path: "/elements/hf-box" });
+    const newScript = String(result.forward[1]?.value ?? "");
+    expect(newScript).not.toContain("hf-box");
+  });
+
+  it("inverse restores element AND script", () => {
+    const parsed = fresh();
+    const { inverse } = applyOp(parsed, { type: "removeElement", target: "hf-box" });
+    // inverse[0] = restore element, inverse[1] = restore script
+    expect(inverse).toHaveLength(2);
+    expect(inverse[0]?.op).toBe("add");
+    expect(inverse[0]?.path).toBe("/elements/hf-box");
+    expect(inverse[1]?.op).toBe("replace");
+    expect(inverse[1]?.path).toBe("/script/gsap");
+    const restoredScript = String(inverse[1]?.value ?? "");
+    expect(restoredScript).toContain("hf-box");
+  });
+
+  it("applying inverse restores element and GSAP script to original", () => {
+    const parsed = fresh();
+    const origScript = getScript(parsed);
+    const { inverse } = applyOp(parsed, { type: "removeElement", target: "hf-box" });
+    applyPatchesToDocument(parsed, inverse);
+    expect(parsed.document.querySelector('[data-hf-id="hf-box"]')).not.toBeNull();
+    expect(getScript(parsed)).toBe(origScript);
+  });
+
+  it("emits only element patch when composition has no GSAP script", () => {
+    const noScriptHtml = `<div data-hf-id="hf-stage" data-hf-root style="width:1280px;height:720px">
+  <div data-hf-id="hf-box"></div>
+</div>`.trim();
+    const parsed = parseMutable(noScriptHtml);
+    const result = applyOp(parsed, { type: "removeElement", target: "hf-box" });
+    expect(result.forward).toHaveLength(1);
+    expect(result.forward[0]?.op).toBe("remove");
+  });
+
+  it("does not remove animations targeting other elements", () => {
+    const twoTweenScript = `var tl = gsap.timeline({ paused: true });
+tl.to("[data-hf-id=\\"hf-box\\"]", { opacity: 1, duration: 0.5 }, 0);
+tl.to("[data-hf-id=\\"hf-stage\\"]", { scale: 1.05, duration: 1 }, 0);
+window.__timelines["t"] = tl;`;
+    const parsed = fresh(twoTweenScript);
+    const result = applyOp(parsed, { type: "removeElement", target: "hf-box" });
+    const newScript = String(result.forward[1]?.value ?? "");
+    expect(newScript).not.toContain("hf-box");
+    expect(newScript).toContain("hf-stage");
+  });
+});

packages/sdk/src/engine/mutate.ts

@@ -344,9 +344,7 @@ function handleSetTiming(
     // so without this the runtime would overwrite our attribute edits on next init.
     if (parsedGsap && currentScript) {
       for (const { id: animId, animation } of parsedGsap.located) {
-        const sel = animation.targetSelector;
-        if (sel !== `[data-hf-id="${id}"]` && sel !== `[data-hf-id='${id}']` && sel !== `#${id}`)
-          continue;
+        if (!selectorMatchesId(animation.targetSelector, id)) continue;
         const updates: Partial<GsapAnimation> = {};
         if (timing.start !== undefined && newStart !== null) updates.position = newStart;
         if (timing.duration !== undefined && newDuration !== null) updates.duration = newDuration;
@@ -398,6 +396,9 @@ function handleSetHold(
 
 function handleRemoveElement(parsed: ParsedDocument, ids: HfId[]): MutationResult {
   const result: MutationResult = { forward: [], inverse: [] };
+  const origScript = getGsapScript(parsed.document);
+  let currentScript = origScript;
+
   for (const id of ids) {
     const el = findById(parsed.document, id);
     if (!el) continue;
@@ -411,7 +412,17 @@ function handleRemoveElement(parsed: ParsedDocument, ids: HfId[]): MutationResul
     const path = elementPath(id);
     result.forward.push(patchRemove(path));
     result.inverse.push(patchAdd(path, { html, parentId, siblingIndex }));
+
+    if (currentScript) currentScript = cascadeRemoveAnimations(currentScript, id);
+  }
+
+  if (origScript && currentScript && currentScript !== origScript) {
+    setGsapScript(parsed.document, currentScript);
+    const gsapResult = gsapScriptChange(origScript, currentScript);
+    result.forward.push(...gsapResult.forward);
+    result.inverse.push(...gsapResult.inverse);
   }
+
   return result;
 }
 
@@ -487,6 +498,28 @@ function handleSetVariableValue(
   return { forward: [p.forward], inverse: [p.inverse] };
 }
 
+// ─── GSAP selector helpers ───────────────────────────────────────────────────
+
+function selectorMatchesId(selector: string, id: HfId): boolean {
+  return (
+    selector === `[data-hf-id="${id}"]` ||
+    selector === `[data-hf-id='${id}']` ||
+    selector === `#${id}`
+  );
+}
+
+function cascadeRemoveAnimations(script: string, id: HfId): string {
+  const parsedGsap = parseGsapScriptAcornForWrite(script);
+  if (!parsedGsap) return script;
+  let current = script;
+  for (const { id: animId, animation } of parsedGsap.located) {
+    if (selectorMatchesId(animation.targetSelector, id)) {
+      current = removeAnimationFromScript(current, animId);
+    }
+  }
+  return current;
+}
+
 // ─── setClassStyle handler ────────────────────────────────────────────────────
 
 function handleSetClassStyle(

packages/sdk/src/session.test.ts

@@ -149,3 +149,68 @@ describe("batch rollback on throw", () => {
     expect(comp.getElement("hf-title")?.inlineStyles["color"]).toBe("#fff");
   });
 });
+
+// ─── canUndo / canRedo ────────────────────────────────────────────────────────
+
+describe("canUndo / canRedo", () => {
+  it("returns false before any mutation", async () => {
+    const comp = await openComposition(BASE_HTML);
+    expect(comp.canUndo()).toBe(false);
+    expect(comp.canRedo()).toBe(false);
+  });
+
+  it("canUndo true after a mutation, false after undoing back to start", async () => {
+    const comp = await openComposition(BASE_HTML);
+    comp.setStyle("hf-title", { color: "#ff0000" });
+    expect(comp.canUndo()).toBe(true);
+    expect(comp.canRedo()).toBe(false);
+
+    comp.undo();
+    expect(comp.canUndo()).toBe(false);
+    expect(comp.canRedo()).toBe(true);
+  });
+
+  it("canRedo cleared after a new mutation", async () => {
+    const comp = await openComposition(BASE_HTML);
+    comp.setStyle("hf-title", { color: "#ff0000" });
+    comp.undo();
+    expect(comp.canRedo()).toBe(true);
+
+    comp.setStyle("hf-title", { color: "#00ff00" });
+    expect(comp.canRedo()).toBe(false);
+  });
+
+  it("returns false in embedded (T3) mode — no history", async () => {
+    const comp = await openComposition(BASE_HTML, { overrides: {} });
+    comp.setStyle("hf-title", { color: "#ff0000" });
+    expect(comp.canUndo()).toBe(false);
+    expect(comp.canRedo()).toBe(false);
+  });
+});
+
+// ─── override-set orphan cleanup ──────────────────────────────────────────────
+
+describe("override-set orphan cleanup on removeElement", () => {
+  it("purges property keys for removed element from the override-set", async () => {
+    const comp = await openComposition(BASE_HTML);
+    comp.setStyle("hf-title", { color: "#ff0000", fontSize: "96px" });
+    expect(Object.keys(comp.getOverrides())).toContain("hf-title.style.color");
+
+    comp.removeElement("hf-title");
+    const overrides = comp.getOverrides();
+    // removal marker present
+    expect(overrides["hf-title"]).toBeNull();
+    // orphan property keys gone
+    expect(Object.keys(overrides)).not.toContain("hf-title.style.color");
+    expect(Object.keys(overrides)).not.toContain("hf-title.style.fontSize");
+  });
+
+  it("property keys for other elements are unaffected", async () => {
+    const comp = await openComposition(BASE_HTML);
+    comp.setStyle("hf-title", { color: "#ff0000" });
+    comp.setStyle("hf-sub", { opacity: "1" });
+    comp.removeElement("hf-title");
+    const overrides = comp.getOverrides();
+    expect(overrides["hf-sub.style.opacity"]).toBe("1");
+  });
+});

packages/sdk/src/session.ts

@@ -147,6 +147,14 @@ class CompositionImpl implements Composition {
     this.historyModule?.redo();
   }
 
+  canUndo(): boolean {
+    return this.historyModule?.canUndo() ?? false;
+  }
+
+  canRedo(): boolean {
+    return this.historyModule?.canRedo() ?? false;
+  }
+
   // ── Query API (F1) ───────────────────────────────────────────────────────────
 
   getElements(): ElementSnapshot[] {
@@ -228,6 +236,19 @@ class CompositionImpl implements Composition {
       }
     }
 
+    // Purge orphan property keys for removed elements so the override-set stays
+    // compact and a future T3 session doesn't replay stale properties onto a
+    // non-existent element.
+    for (const p of forward) {
+      const elemMatch = /^\/elements\/([^/]+)$/.exec(p.path);
+      if (p.op === "remove" && elemMatch) {
+        const id = elemMatch[1]!;
+        for (const key of Object.keys(this.overrides)) {
+          if (key.startsWith(`${id}.`)) delete this.overrides[key];
+        }
+      }
+    }
+
     if (this.batchDepth > 0) {
       this.batchForward.push(...forward);
       this.batchInverse.push(...inverse);

packages/sdk/src/types.ts

@@ -229,6 +229,8 @@ export interface Composition {
   removeGsapTween(animationId: string): void;
   undo(): void;
   redo(): void;
+  canUndo(): boolean;
+  canRedo(): boolean;
 
   // ── Query API (F1) ─────────────────────────────────────────────────────────
   getElements(): ElementSnapshot[];