content: /*
   * Copyright 2022 Aurélien Gâteau <mail@agateau.com>
   *
   * This file is part of Pixel Wheels.
   *
   * 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.
   */
  package com.agateau.pixelwheels.tools.trackeditor;
  
  import com.badlogic.gdx.utils.Array;
  
  class EditorActionStack {
      private final Array<EditorAction> mActions = new Array<>();
      int mNextIndex = 0;
  
      public void add(EditorAction action) {
          action.redo();
          if (!mActions.isEmpty()) {
              EditorAction lastAction = mActions.get(mActions.size - 1);
              if (lastAction.mergeWith(action)) {
                  return;
              }
          }
          if (mNextIndex < mActions.size) {
              mActions.removeRange(mNextIndex, mActions.size - 1);
          }
          mActions.add(action);
          ++mNextIndex;
      }
  
      public void undo() {
          if (mNextIndex == 0) {
              return;
          }
          --mNextIndex;
          mActions.get(mNextIndex).undo();
      }
  
      public void redo() {
          if (mNextIndex == mActions.size) {
              return;
          }
          mActions.get(mNextIndex).redo();
          mNextIndex++;
      }
  }
  