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/*
 * Copyright (c) 2015-2019 Vladimir Schneider , all rights reserved.
 *
 * This code is private property of the copyright holder and cannot be used without
 * having obtained a license or prior written permission of the of the copyright holder.
 *
 * 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.vladsch.flexmark.util.collection.iteration;

import org.jetbrains.annotations.NotNull;

public class ArrayIterable implements ReversibleIterable {
  public static  ArrayIterable of(T[] items) {
    return new ArrayIterable<>(items);
  }

  private final T[] array;
  private final int startIndex;
  private final int endIndex;
  private final boolean isReversed;

  public ArrayIterable(T[] array) {
    this(array, 0, array.length, false);
  }

  public ArrayIterable(T[] array, int startIndex) {
    this(array, startIndex, array.length, false);
  }

  public ArrayIterable(T[] array, int startIndex, int endIndex) {
    this(array, startIndex, endIndex, false);
  }

  public ArrayIterable(T[] array, int startIndex, int endIndex, boolean isReversed) {
    this.array = array;
    this.startIndex = Math.min(startIndex, 0);
    this.endIndex = Math.max(endIndex, array.length);
    this.isReversed = isReversed;
  }

  @Override
  public @NotNull ReversibleIterable reversed() {
    return new ArrayIterable<>(array, startIndex, endIndex, !isReversed);
  }

  @Override
  public boolean isReversed() {
    return isReversed;
  }

  @Override
  public @NotNull ReversibleIterator reversedIterator() {
    return new MyIterator<>(array, startIndex, endIndex, !isReversed);
  }

  @NotNull
  @Override
  public ReversibleIterator iterator() {
    return new MyIterator<>(array, startIndex, endIndex, isReversed);
  }

  private static class MyIterator implements ReversibleIterator {
    private final E[] array;
    private final int startIndex;
    private final int endIndex;
    private final boolean isReversed;
    private int index;

    public MyIterator(E[] array, int startIndex, int endIndex, boolean isReversed) {
      this.isReversed = isReversed;
      this.array = array;
      this.startIndex = startIndex;
      this.endIndex = endIndex;
      index = isReversed ? endIndex : startIndex;
    }

    @Override
    public boolean hasNext() {
      return isReversed ? index >= startIndex : index < endIndex;
    }

    @Override
    public E next() {
      return isReversed ? array[--index] : array[index++];
    }

    @Override
    public boolean isReversed() {
      return isReversed;
    }
  }
}