源码快照 @ 2026-09-01 (source-only, 剔除非源码素材)

packages/agent/gui/shared/agentConversation/components/useTurnDisclosureMotion.ts

@@ -0,0 +1,104 @@
+import { useCallback, useRef, useState } from "react";
+import { findMessageLocatorScrollParent } from "./AgentMessageLocatorRail";
+
+interface TurnDisclosureScrollAnchor {
+  release: () => void;
+}
+
+class TurnDisclosureMotionController {
+  private readonly movingTurnKeys = new Set<string>();
+  private scrollAnchor: TurnDisclosureScrollAnchor | null = null;
+
+  setTurnMotionActive(
+    turnKey: string,
+    active: boolean,
+    anchorElement?: HTMLElement | null
+  ): boolean {
+    if (active) {
+      this.movingTurnKeys.add(turnKey);
+      if (anchorElement) {
+        this.scrollAnchor?.release();
+        this.scrollAnchor = lockDisclosureRowPosition(anchorElement);
+      }
+    } else {
+      this.movingTurnKeys.delete(turnKey);
+      if (this.movingTurnKeys.size === 0) {
+        this.scrollAnchor?.release();
+        this.scrollAnchor = null;
+      }
+    }
+    return this.movingTurnKeys.size > 0;
+  }
+}
+
+function lockDisclosureRowPosition(
+  anchorElement: HTMLElement
+): TurnDisclosureScrollAnchor | null {
+  const scrollParent = findMessageLocatorScrollParent(anchorElement);
+  if (!scrollParent) {
+    return null;
+  }
+
+  const anchorTop = anchorElement.getBoundingClientRect().top;
+  const previousOverflowAnchor =
+    scrollParent.style.getPropertyValue("overflow-anchor");
+  const previousOverflowAnchorPriority =
+    scrollParent.style.getPropertyPriority("overflow-anchor");
+  scrollParent.style.setProperty("overflow-anchor", "none");
+
+  const preserveAnchorTop = (): void => {
+    if (!anchorElement.isConnected) {
+      return;
+    }
+    const topDelta = anchorElement.getBoundingClientRect().top - anchorTop;
+    if (Math.abs(topDelta) < 0.5) {
+      return;
+    }
+    scrollParent.scrollTop += topDelta;
+  };
+  scrollParent.addEventListener("scroll", preserveAnchorTop);
+
+  return {
+    release: () => {
+      preserveAnchorTop();
+      scrollParent.removeEventListener("scroll", preserveAnchorTop);
+      if (previousOverflowAnchor) {
+        scrollParent.style.setProperty(
+          "overflow-anchor",
+          previousOverflowAnchor,
+          previousOverflowAnchorPriority
+        );
+      } else {
+        scrollParent.style.removeProperty("overflow-anchor");
+      }
+    }
+  };
+}
+
+export function useTurnDisclosureMotion(): readonly [
+  active: boolean,
+  setTurnMotionActive: (
+    turnKey: string,
+    active: boolean,
+    anchorElement?: HTMLElement | null
+  ) => void
+] {
+  const motionControllerRef = useRef<TurnDisclosureMotionController | null>(
+    null
+  );
+  if (!motionControllerRef.current) {
+    motionControllerRef.current = new TurnDisclosureMotionController();
+  }
+  const motionController = motionControllerRef.current;
+  const [active, setActive] = useState(false);
+  const setTurnMotionActive = useCallback(
+    (turnKey: string, moving: boolean, anchorElement?: HTMLElement | null) => {
+      setActive(
+        motionController.setTurnMotionActive(turnKey, moving, anchorElement)
+      );
+    },
+    [motionController]
+  );
+
+  return [active, setTurnMotionActive];
+}