import java.util.Scanner;
import java.text.DecimalFormat;

public class Calculator 
{
  Scanner scan = new Scanner(System.in);
  //Creates array to hold fifteen references of type Register
  //or of any type that implements Register.
  Register[] items = new Register[15]; 
  //Variable keeps track of the array index.
  int count = 0;
  double rTotal = 0;
  
  
  public static void main(String[] args)
  {
    DecimalFormat fmt = new DecimalFormat("0.##");
    Calculator run = new Calculator();
    run.enterItems();
    //The total cost of all items is printed out with the proper formatting.
    if(run.count != 0)
    {
    System.out.println("The final total is " + fmt.format(run.calcTotal()));
    System.out.println("The total calculated recursivly is " + fmt.format(run.recTotal(run.count-1)));
    }
    else
    {
      System.out.println("No items entered.");
      run.enterItems(); 
    }
  }  
  
  //This method asks the user for input about the items they request, creates objects 
  //of type General or Produce and stores their references in the Register array.
  public void enterItems()
  {
    Produce greens;
    General merchandise;
    int type, sale;
    double price, pound;
    
    System.out.println("Enter 1 for general merchandise and 2 for produce. Enter zero if you have no more items.");
    type = scan.nextInt();
    
    //While statement allows user to stop entering items when they enter the sentinel, 0.
    while (type != 0)
    {
      //Both types of items require the percent off so this question is asked every time the
      //while loop executes.
      System.out.println("Is the item on sale? Please enter the percent off. If it is not "
                           + "on sale please enter zero.");
      sale = scan.nextInt();
      
      //This if-else statement allows the user to chose which type of 
      //object they would like to create the asks them specific questions
      //to obtain information required for the constructor of an object of 
      //that type.
      if(type == 1)
      {
        System.out.println("Now please enter the price of the item.");
        price = scan.nextDouble();
        //General object is created and assigned to an a array reference variable of
        //type Register.  Polymorphism makes this possible.
        items[count] = new General(price,sale);
        //The array index is incremented.
        count++;    
      }
      else
      {
        System.out.println("Now please enter the price per pound of the item.");
        price = scan.nextDouble();
        System.out.println("What is the item weight(lbs)?");
        pound = scan.nextDouble();
        //Produce object is created and assigned to an a array reference variable of
        //type Register.  Polymorphism makes this possible.
        items[count] = new Produce(price, sale, pound);
        //The array index is incremented.
        count++;     
      }
      System.out.println("Enter 1 for general merchandise and 2 for produce. Enter zero if you have no more items.");
      //Reassigns the variable "type" to be checked by the next iteration of the while loop 
      //and the enclosed if-else statement.
      type = scan.nextInt();
    }
  }
  
  //Runs through each item stored in the array and calls its corresponding total()
  //method.  The value returned from each method call is added to the variable "total"
  //which represents the total cost of all items in the array.
  public double calcTotal()
  {
    double total = 0;
    for(int i = 0;i<count;i++)
    {
      total += items[i].total();
    }
    return total;   
  }

  //Method calculates the sum using recursion.  The number of elements to sum is passed
  //as a parameter to this method.  The value of each item in the array is added to the variable
  //rTotal when the method is called.
  public double recTotal(int rCount)
  {
    //Base case.
    if(rCount == 0)
    {
      rTotal += items[rCount].total();
      return rTotal;
    }
    else
    {
      rTotal += items[rCount].total();
      return (recTotal(rCount-1)); 
    }
  }


}