Squash Odysseus development history

static/js/editor/direct-manipulation-session.js

@@ -0,0 +1,81 @@
+/** Shared lifecycle guard for frame-style pointer interactions. */
+
+export function createDirectManipulationSession({
+  name = 'interaction',
+  getContext = () => null,
+  isContextCurrent = () => true,
+  onCancel = () => {},
+} = {}) {
+  let active = null;
+  let nextId = 1;
+
+  const pointerMatches = event => {
+    if (!active || active.pointerId == null || event?.pointerId == null) return true;
+    return active.pointerId === event.pointerId;
+  };
+
+  const releaseCapture = session => {
+    if (!session?.captureTarget || session.pointerId == null) return;
+    try { session.captureTarget.releasePointerCapture(session.pointerId); } catch {}
+  };
+
+  const contextIsCurrent = () => active && isContextCurrent(active.context, active.data);
+
+  function begin(event, data = {}, options = {}) {
+    if (active) cancel('restarted');
+    const pointerId = Number.isFinite(event?.pointerId) ? event.pointerId : null;
+    const captureTarget = options.captureTarget || null;
+    active = {
+      id: nextId++,
+      name,
+      pointerId,
+      captureTarget,
+      context: getContext(),
+      data,
+    };
+    if (captureTarget && pointerId != null) {
+      try { captureTarget.setPointerCapture(pointerId); } catch {}
+    }
+    return active;
+  }
+
+  function update(event, callback) {
+    if (!active || !pointerMatches(event)) return false;
+    if (!contextIsCurrent()) {
+      cancel('stale-context');
+      return false;
+    }
+    callback?.(active.data, active);
+    return true;
+  }
+
+  function commit(event, callback) {
+    if (!active || !pointerMatches(event)) return false;
+    if (!contextIsCurrent()) {
+      cancel('stale-context');
+      return false;
+    }
+    const completed = active;
+    active = null;
+    releaseCapture(completed);
+    callback?.(completed.data, completed);
+    return true;
+  }
+
+  function cancel(reason = 'cancelled') {
+    if (!active) return false;
+    const cancelled = active;
+    active = null;
+    releaseCapture(cancelled);
+    onCancel(cancelled.data, reason, cancelled);
+    return true;
+  }
+
+  return {
+    begin,
+    update,
+    commit,
+    cancel,
+    get active() { return active; },
+  };
+}