/*
 * Copyright (c) 2022-2023 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

export class EditStack<T> {
  private stack: T[] = [];
  private currentPosition: number = -1;

  isRedoValid(): boolean {
    return (this.currentPosition < this.stack.length - 1);
  }

  isUndoValid(): boolean {
    return (this.currentPosition >= 0);
  }

  redo(): number {
    if (this.isRedoValid()) {
      this.currentPosition++;
    }
    return this.currentPosition;
  }

  undo(): number {
    if (this.isUndoValid()) {
      this.currentPosition--;
    }
    return this.currentPosition;
  }

  reset(): void {
    this.stack.length = 0;
    this.currentPosition = -1;
  }

  getLength(): number {
    return this.stack.length;
  }

  getPosition(): number {
    return this.currentPosition;
  }

  at(index: number): T {
    return this.stack[index];
  }

  push(obj: T): void {
    let reserveLength = this.currentPosition + 1;
    if (reserveLength < this.stack.length) {
      this.stack.length = reserveLength;
    }
    this.currentPosition = this.stack.push(obj) - 1;
  }

  forEach(action: Function, count: number = this.currentPosition): void {
    for (let i = 0; i <= count; ++i) {
      action(this.stack[i]);
    }
  }
}