/* ShoppingList.java - define a shopping list.
 * The attribute will be an array of Items, where an Item
 *   is just a name and a price.
 * The shopping list info will be read in from a file.  To make
 *   the implementation a little simpler, let's assume that the
 *   input file begins with a number that tells us how many items
 *   are on the list.  This will save us the trouble of having to
 *   read the list twice (or using a data structure other than an array.)
 * Let's assume the rest of the input file has one item per line
 *   and the format is the name followed by price.
 * Let's assume the name has only one word.  (Think about how we
 *   would handle multi-word names.)
 */
import java.io.FileNotFoundException;
import java.io.FileInputStream;
import java.util.Scanner;

public class ShoppingList
{
  private Item [] list;

  /* default constructor - read from input file
   */
  public ShoppingList() throws FileNotFoundException
  {
    System.out.printf("Enter name of input file:  ");
    Scanner kbd = new Scanner(System.in);
    String fileName = kbd.nextLine();
    Scanner in = new Scanner(new FileInputStream(fileName));  // don't forget "new"

    // Find size of the list.  Allocate space for shopping list.
    int numItems = in.nextInt();
    list = new Item [numItems];

    // Read the items one at a time.
    // Each line has a price.  After the price, the entire rest of
    //   the line will be the name of the item.
    // If the item name came first, this would have been a little
    //   more difficult to do.
    int index = 0;
    while (index < numItems)
    {
      String name = in.next();
      double price = in.nextDouble();

      // Create a new object and put it into the array.
      Item thing = new Item(name, price);
      list[index] = thing;

      index = index + 1;
    }
  }

  /* findTotal - go thru the entire array and add up the prices
   * of the items.  This is a very useful function!
   * Many functions we'll write in the future will look like this.
   * Note carefully the expression "list[index].getPrice()"
   */
  public double findTotal()
  {
    double sum = 0.00;
    int index = 0;
    while (index < list.length)
    {
      sum = sum + list[index].getPrice();
      index = index + 1;
    }
    return sum;
  }

  /* toString() will generate a text representation of the list,
   *   including the total.  We'll format the output so it looks good.
   * Note that we need to use a loop, and slowly build the string.
   * We'll make use of the Item toString().  When we do so, we need to
   *   remember to append a \n because there isn't one at the end of the
   *   item's string.
   */
  public String toString()
  {
    String build = "";
    int index = 0;
    while (index < list.length)
    {
      build = build + list[index].toString() + "\n";
      index = index + 1;
    }

    // Get ready for the total
    // Let's assume the shopping list has a width of 30 characters.
    build = build + "------------------------------\n";
    build = build + String.format("TOTAL %24.2f\n", findTotal());

    return build;
  }
}