package VL13.Aufgabe02;

public class MyQueue<T> {
  private Object[] myArray;
  private int numberOfElements;
  private int maxSize;

  public MyQueue() {
    this.numberOfElements = 0;
    this.maxSize = 100;
    myArray = new Object[this.maxSize];
  }

  public void add(T t) {
    this.myArray[this.numberOfElements] = t;
    this.numberOfElements++;
    this.adjustInternalArray();
  }

  @SuppressWarnings("unchecked")
  public T get() {
    T retValue = (T) this.myArray[0];

    for (int i = 0; i < this.numberOfElements; i++) {
      this.myArray[i] = this.myArray[i + 1];
    }

    this.numberOfElements--;
    this.adjustInternalArray();
    return retValue;
  }

  public int size() {
    return this.numberOfElements;
  }

  public int internalSize() {
    return this.maxSize;
  }

  private void adjustInternalArray() {
    final int MIN_SIZE = 20;

    while (this.numberOfElements <= Math.ceil(this.maxSize * 0.2) && this.maxSize > MIN_SIZE) {
      this.maxSize = Math.max(this.maxSize / 2, 20);
      Object[] myOldArray = this.myArray;
      this.myArray = new Object[this.maxSize];

      for (int i = 0; i < this.myArray.length; i++) {
        this.myArray[i] = myOldArray[i];
      }
    }

    while (this.numberOfElements >= Math.ceil(this.maxSize * 0.8)) {
      this.maxSize = this.maxSize * 2;
      Object[] myOldArray = this.myArray;
      this.myArray = new Object[this.maxSize];

      for (int i = 0; i < myOldArray.length; i++) {
        this.myArray[i] = myOldArray[i];
      }
    }
  }
}