frontend/src/editor/extensions/collaboration-undo.ts

import { Extension } from "@tiptap/core";
import { UndoManager } from "yjs";
import { yUndoPluginKey } from "@tiptap/y-tiptap";

export interface CollaborationUndoOptions {
  onUndoManagerReady?: (manager: UndoManager) => void;
}

/**
 * Thin extension that exposes the UndoManager created by @tiptap/extension-collaboration v3.
 * The actual undo/redo commands and shortcuts are handled by the Collaboration extension itself.
 * This extension only reads the UndoManager from the yUndoPlugin state and
 * exposes it via onUndoManagerReady for external consumers (e.g. agent chat batching).
 */
export const CollaborationUndo = Extension.create<CollaborationUndoOptions>({
  name: "collaborationUndoBridge",

  addOptions() {
    return {
      onUndoManagerReady: undefined,
    };
  },

  addStorage() {
    return {
      undoManager: null as UndoManager | null,
    };
  },

  onCreate() {
    const state = this.editor.state;
    const undoState = yUndoPluginKey.getState(state);
    if (undoState?.undoManager) {
      this.storage.undoManager = undoState.undoManager;
      this.options.onUndoManagerReady?.(undoState.undoManager);
    }
  },
});