/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow strict
 */
import type {LexicalExtension, ExtensionConfigBase, EditorState, BaseSelection, LexicalEditor} from 'lexical';
import type {ReadonlySignal, Signal} from '@lexical/extension';

export type HistoryStateEntry = {
  editor: LexicalEditor,
  editorState: EditorState,
  undoSelection?: BaseSelection | null,
};
export type HistoryState = {
  current: null | HistoryStateEntry,
  redoStack: HistoryStateEntry[],
  undoStack: HistoryStateEntry[],
};
declare export function registerHistory(
  editor: LexicalEditor,
  historyState: HistoryState,
  delay: number,
  dateNow?: () => number,
  onHistoryStateChange?: (historyState: HistoryState) => void,
): () => void;
declare export function createEmptyHistoryState(): HistoryState;

export type HistoryConfig = {
  delay: number;
  createInitialHistoryState: (editor: LexicalEditor) => HistoryState;
  disabled: boolean;
}

export type HistoryExtensionOutput = {
  /** `true` when there is at least one entry in the redo stack. */
  canRedo: ReadonlySignal<boolean>,
  /** `true` when there is at least one entry in the undo stack. */
  canUndo: ReadonlySignal<boolean>,
  delay: Signal<number>,
  disabled: Signal<boolean>,
  historyState: Signal<HistoryState>,
  now: Signal<() => number>,
};

declare export var HistoryExtension: LexicalExtension<HistoryConfig, "@lexical/history/History", HistoryExtensionOutput, void>;
declare export var SharedHistoryExtension: LexicalExtension<ExtensionConfigBase, "@lexical/history/SharedHistory", void, void>;