//File: LifoList.java
//Name: Trai Pham
//Date: 02/09/2020
//Course: CSE 8B

/**This class extends the OrderedDS class. Implement all methods in OrderedDS
and DataStructure classes and BasicMethods interface
This class allows you to input elements from left, but the last element would
always be in the far left part and the first element would be in the far right
*/
public class LifoList extends OrderedDS{
//holds the max size for array
  private int maxSize;
  private int indexAt;
  private static final String EMPTY_ERROR = "LifoList is empty";
  private static final String MAX_SIZE_ERROR = "LifoList maximum limit reached";

//default constructor
  public LifoList(){
    this.maxSize =0;
    this.array = null;
    this.indexAt = 0;
  }
//initializes the size of the LifoList
  public LifoList(int maxSize){
    if(maxSize < 0){
      this.maxSize = 0;
      this.array = null;
    }
    else{
      this.maxSize = maxSize;
      this.array = new int [this.maxSize];
    }
  }
//creates a deep copy of object s
  public LifoList(LifoList s){
    if( s == null){
      this.maxSize = 0;
      this.array = null;
    }
    else {
      this.maxSize = s.maxSize;
      for(int i = 0; i < this.maxSize; i++){
        this.array[i] = s.array[i];
      }
    }
  }

  public void add(int element){
    if(this.array == null || this.indexAt == this.array.length){
      System.out.println(MAX_SIZE_ERROR);
      return;
    }
    else{
//adds the elements from left to right
        for(int i = this.indexAt; i > 0; i--){
          this.array[i] = this.array[i-1];
        }
        this.array[0] = element;
        this.indexAt++;
    }
  }

  public int delete(){
//empty error check
    if(this.indexAt == 0|| this.array == null){
      System.out.println(EMPTY_ERROR);
      return -1;
    }
    else{
      int reserved = this.array[0];
      for( int i = 1; i < this.indexAt; i++){
          this.array[i-1] = this.array[i];
      }
      indexAt--;
      return reserved;
      }
  }

  public int peek(){
//empty error check
    if(this.indexAt == 0 || this.array == null){
      System.out.println(EMPTY_ERROR);
      return -1;
    }
    else{
//returns first element inserted in list
      return this.array[0];
    }
  }
//size of the list
  public int size(){
    return this.indexAt;
  }

  public String toString(){
    String output = "";
    if(this.indexAt == this.array.length + 1 || this.array == null){
      return "";
    }
    else{

      StringBuilder a = new StringBuilder();
      if(this.indexAt != 0){
      output = this.array[0] + "";
      a.insert(0, output);
      for(int i = 1; i < this.indexAt; i++){
        a.append ("-" + this.array[i]);
      }
    }
    return a.toString();
  }

  }

  public static void main (String [] args){
    LifoList a = new LifoList(5);
    // System.out.println(a.array.length); //gives you length of the array
    System.out.println(a);
    a.add(2);
    System.out.println(a);
    a.add(5);
    System.out.println(a);
    a.add(4);
    System.out.println(a);
    a.add(25);
    System.out.println(a);
    a.add(9);
    System.out.println(a);
    a.add(10);
    // System.out.println(a);
    // a.add(9);
    System.out.println("Testing add method");
    a.delete();
    System.out.println(a);
    a.delete();
    System.out.println(a);
    // a.delete();
    // System.out.println(a);
    System.out.println("Testing deleting method");
    System.out.println(a.peek());
    System.out.println("Returning the top number");
    // // System.out.println("Testing delete method");
    System.out.println(a.size());
    // System.out.println("Counting number of elements");
  }
}