feat(studio): shift GSAP animation positions on clip drag

packages/core/src/parsers/gsapParser.test.ts

@@ -19,6 +19,7 @@ import {
   addAnimationWithKeyframesToScript,
   splitAnimationsInScript,
   splitIntoPropertyGroups,
+  shiftPositionsInScript,
 } from "./gsapParser.js";
 import type { GsapAnimation } from "./gsapParser.js";
 import { classifyPropertyGroup, classifyTweenPropertyGroup } from "./gsapConstants.js";
@@ -2275,3 +2276,57 @@ describe("splitIntoPropertyGroups", () => {
     }
   });
 });
+
+describe("shiftPositionsInScript", () => {
+  it("shifts all numeric positions for the target selector", () => {
+    const script = `const tl = gsap.timeline({ paused: true });
+tl.from("#hero", { opacity: 0, duration: 1 }, 0);
+tl.to("#hero", { opacity: 0, duration: 0.5 }, 2.5);
+tl.from("#bg", { scale: 0, duration: 1 }, 1);`;
+    const result = shiftPositionsInScript(script, "#hero", 3);
+    const parsed = parseGsapScript(result);
+    const hero = parsed.animations.filter((a) => a.targetSelector === "#hero");
+    expect(hero[0].position).toBe(3);
+    expect(hero[1].position).toBe(5.5);
+    const bg = parsed.animations.find((a) => a.targetSelector === "#bg");
+    expect(bg!.position).toBe(1);
+  });
+
+  it("clamps negative-going positions to zero", () => {
+    const script = `const tl = gsap.timeline({ paused: true });
+tl.to("#el", { x: 100, duration: 1 }, 0.3);
+tl.to("#el", { y: 50, duration: 1 }, 1.5);`;
+    const result = shiftPositionsInScript(script, "#el", -1.0);
+    const parsed = parseGsapScript(result);
+    const anims = parsed.animations.filter((a) => a.targetSelector === "#el");
+    expect(anims[0].position).toBe(0);
+    expect(anims[1].position).toBe(0.5);
+  });
+
+  it("returns the original script when delta is zero", () => {
+    const script = `const tl = gsap.timeline({ paused: true });
+tl.to("#el", { x: 100, duration: 1 }, 2);`;
+    expect(shiftPositionsInScript(script, "#el", 0)).toBe(script);
+  });
+
+  it("does not collide when two tweens have adjacent positions (Via's race case)", () => {
+    const script = `const tl = gsap.timeline({ paused: true });
+tl.to("#burst", { opacity: 1, duration: 0.5 }, 1.0);
+tl.to("#burst", { opacity: 0, duration: 0.5 }, 1.5);`;
+    const result = shiftPositionsInScript(script, "#burst", 0.5);
+    const parsed = parseGsapScript(result);
+    const burst = parsed.animations.filter((a) => a.targetSelector === "#burst");
+    expect(burst[0].position).toBe(1.5);
+    expect(burst[1].position).toBe(2);
+  });
+
+  it("skips string positions", () => {
+    const script = `const tl = gsap.timeline({ paused: true });
+tl.to("#el", { x: 100, duration: 1 }, 2);
+tl.to("#el", { y: 50, duration: 1 }, "+=0.5");`;
+    const result = shiftPositionsInScript(script, "#el", 1);
+    const parsed = parseGsapScript(result);
+    expect(parsed.animations[0].position).toBe(3);
+    expect(parsed.animations[1].position).toBe("+=0.5");
+  });
+});

packages/core/src/parsers/gsapParser.ts

@@ -1322,6 +1322,29 @@ export function updateAnimationInScript(
   return recast.print(parsed.ast).code;
 }
 
+export function shiftPositionsInScript(
+  script: string,
+  targetSelector: string,
+  delta: number,
+): string {
+  let parsed: ParsedGsapAst;
+  try {
+    parsed = parseGsapAst(script);
+  } catch (e) {
+    console.warn("[gsap-parser] shiftPositionsInScript parse failed:", e);
+    return script;
+  }
+  let changed = false;
+  for (const entry of parsed.located) {
+    if (entry.animation.targetSelector !== targetSelector) continue;
+    if (typeof entry.animation.position !== "number") continue;
+    const newPos = Math.max(0, Math.round((entry.animation.position + delta) * 1000) / 1000);
+    applyUpdatesToCall(entry.call, { position: newPos });
+    changed = true;
+  }
+  return changed ? recast.print(parsed.ast).code : script;
+}
+
 function updateAnimationSelector(script: string, animationId: string, newSelector: string): string {
   let parsed: ParsedGsapAst;
   try {

packages/core/src/studio-api/routes/files.ts

@@ -466,6 +466,11 @@ type GsapMutationRequest =
   | {
       type: "delete-all-for-selector";
       targetSelector: string;
+    }
+  | {
+      type: "shift-positions";
+      targetSelector: string;
+      delta: number;
     };
 
 // ── GSAP mutation executor ──────────────────────────────────────────────────
@@ -715,6 +720,12 @@ async function executeGsapMutation(
       const result = splitIntoPropertyGroups(block.scriptText, body.animationId);
       return result.script;
     }
+    case "shift-positions": {
+      const { targetSelector, delta } = body;
+      if (!targetSelector || typeof delta !== "number" || delta === 0) return block.scriptText;
+      const { shiftPositionsInScript } = parser;
+      return shiftPositionsInScript(block.scriptText, targetSelector, delta);
+    }
     default:
       return respond({ error: `unknown mutation type: ${(body as { type: string }).type}` }, 400);
   }

packages/studio/src/components/editor/GestureTrailOverlay.tsx

@@ -6,7 +6,7 @@ interface GestureTrailOverlayProps {
   sampleCount?: number;
   trail?: Array<{ x: number; y: number }>;
   simplifiedPoints?: Map<number, Record<string, number>>;
-  canvasRect: { left: number; top: number; width: number; height: number };
+  canvasRect: { left: number; top: number; width: number; height: number } | null;
   compositionSize?: { width: number; height: number };
   mode: "recording" | "preview";
   accentColor?: string;
@@ -22,6 +22,8 @@ export const GestureTrailOverlay = memo(function GestureTrailOverlay({
   mode,
   accentColor = "#3CE6AC",
 }: GestureTrailOverlayProps) {
+  if (!canvasRect) return null;
+
   const trailPoints = useMemo(() => {
     if (trail && trail.length > 1) {
       return trail.map((p) => `${p.x - canvasRect.left},${p.y - canvasRect.top}`).join(" ");

packages/studio/src/hooks/timelineEditingHelpers.ts

@@ -144,5 +144,34 @@
   return data.content;
 }
 
+/**
+ * Shift all GSAP animation positions targeting a given element by a time delta.
+ * Calls the server-side GSAP mutation endpoint which uses the AST-based parser.
+ */
+export async function shiftGsapPositions(
+  projectId: string,
+  filePath: string,
+  elementId: string,
+  delta: number,
+): Promise<void> {
+  if (delta === 0 || !elementId) return;
+  const res = await fetch(
+    `/api/projects/${projectId}/gsap-mutations/${encodeURIComponent(filePath)}`,
+    {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({
+        type: "shift-positions",
+        targetSelector: `#${elementId}`,
+        delta,
+      }),
+    },
+  );
+  if (!res.ok) {
+    const err = await res.json().catch(() => null);
+    throw new Error((err as { error?: string })?.error ?? "shift-positions failed");
+  }
+}
+
 // Re-export applyPatchByTarget for use in the hook (avoids double import in callers)
 export { applyPatchByTarget, formatTimelineAttributeNumber };

packages/studio/src/hooks/useTimelineEditing.ts

@@ -26,6 +26,7 @@ import {
   readFileContent,
   applyPatchByTarget,
   formatTimelineAttributeNumber,
+  shiftGsapPositions,
 } from "./timelineEditingHelpers";
 import type { PersistTimelineEditInput } from "./timelineEditingHelpers";
 
@@ -122,6 +123,8 @@ export function useTimelineEditing({
         ["data-start", formatTimelineAttributeNumber(updates.start)],
         ["data-track-index", String(updates.track)],
       ]);
+      const delta = updates.start - element.start;
+      const filePath = element.sourceFile || activeCompPath || "index.html";
       return enqueueEdit(element, "Move timeline clip", (original, target) => {
         let patched = applyPatchByTarget(original, target, {
           type: "attribute",
@@ -133,9 +136,16 @@ export function useTimelineEditing({
           property: "track-index",
           value: String(updates.track),
         });
+      }).then(() => {
+        const pid = projectIdRef.current;
+        if (delta !== 0 && element.domId && pid) {
+          return shiftGsapPositions(pid, filePath, element.domId, delta)
+            .then(() => reloadPreview())
+            .catch((err) => console.error("[Timeline] Failed to shift GSAP positions", err));
+        }
       });
     },
-    [previewIframeRef, enqueueEdit],
+    [previewIframeRef, enqueueEdit, activeCompPath, reloadPreview],
   );
 
   const handleTimelineElementResize = useCallback(
@@ -147,9 +157,6 @@ export function useTimelineEditing({
         ["data-start", formatTimelineAttributeNumber(updates.start)],
         ["data-duration", formatTimelineAttributeNumber(updates.duration)],
       ];
-      // A start-edge trim advances the media-start offset (skips into the
-      // source). Patch it live too — otherwise the iframe keeps the old offset
-      // and the clip only repositions instead of trimming the audio.
       if (updates.playbackStart != null) {
         const liveAttr =
           element.playbackStartAttr === "playback-start"
@@ -178,9 +185,9 @@ export function useTimelineEditing({
           });
         }
         return patched;
-      });
+      }).then(() => reloadPreview());
     },
-    [previewIframeRef, enqueueEdit],
+    [previewIframeRef, enqueueEdit, reloadPreview],
   );
 
   const handleTimelineElementDelete = useCallback(

packages/studio/src/player/components/TimelineClipDiamonds.tsx

@@ -108,7 +108,9 @@ export const TimelineClipDiamonds = memo(function TimelineClipDiamonds({
   const diamondSize = Math.round(clipHeightPx * (beatsActive ? 0.45 : DIAMOND_RATIO));
   const half = diamondSize / 2;
   const centerY = beatsActive ? BEAT_BAND_H + (clipHeightPx - BEAT_BAND_H) / 2 : clipHeightPx / 2;
-  const sorted = keyframesData.keyframes.slice().sort((a, b) => a.percentage - b.percentage);
+  const sorted = keyframesData.keyframes
+    .filter((kf) => kf.percentage >= 0 && kf.percentage <= 100)
+    .sort((a, b) => a.percentage - b.percentage);
   const baseColor = isSelected ? accentColor : "#a3a3a3";
   const baseOpacity = isSelected ? 0.4 : 0.25;