/*
 * PART 1 - Create an Ontario Item
 *
 * An OntarioItem object cannot be modified.  The total price is
 * computed based on the quantity, unit price, and tax rate which
 * are passed into the constructor.  
 */
public class OntarioItem implements Item {
    final static float ONTARIO_TAX = (float) 0.15;

    /* The data members are final below to re-inforce the notion that
     * the values cannot change once they are initialized in the
     * constructor
     */

    final private int    m_quantity;
    final private String m_id;         // Item id
    final private String m_name;
    final private float  m_unitPrice;
    final private float  m_totalPrice;


    /* Decimal constants in java are double.  It is nice to have
     * a constructor which will accept constants without needing a 
     * cast.
     */
    public OntarioItem(int quantity, String id, 
		       String name,  double unitPrice)
    {
	this(quantity, id, name, (float) unitPrice);
    }

    public OntarioItem(int quantity, String id, 
		       String name,  float unitPrice)
    {
	Util.assert(quantity    >= 0,    "Quantity must be non-negative");
	Util.assert(id          != null, "Id is null");
	Util.assert(name        != null, "Name is null");
	Util.assert(unitPrice   >= 0,    "Unit Price must be non-negative");
	Util.assert(ONTARIO_TAX >= 0,    "Tax rate must be >= 0");

	m_quantity   = quantity;
	m_id         = id;
	m_name       = name;
	m_unitPrice  = unitPrice;

	// round to two decimals!
	m_totalPrice = ((int) (100 * m_unitPrice * m_quantity * (1 + ONTARIO_TAX)))/100.0F;

    }

    public int getQuantity() {
	return m_quantity;
    }

    public String getItemId() {
	return m_id;
    }
    
    public String getItemName() {
	return m_name;
    }

    public float getUnitPrice() {
	return m_unitPrice;
    }

    public float getTotalPrice() {
	return m_totalPrice;
    }

    /*******************************
     * Inherited Methods (from Object)
     * equals is necessary if we wish to put an Item 
     * into a Hashtable.  see part 3 of assignment.
     *******************************/

    public String toString() {
	return "OntarioItem: "    + getItemName() + 
	       " - Units: "       + getQuantity() + 
      	       " - Total Price: " + getTotalPrice();
    }

    /**
     *  Two items are equal if:
     *  they are instances of the same class (OntarioItem) AND
     *  their ID's are the same AND
     *  the items have the same name AND
     *  the items have the same unit price
     */
    public boolean equals(Object o) {
	if (o == null || !(o instanceof OntarioItem)) { return false; }

	OntarioItem other = (OntarioItem) o;

	return other.m_id.equals(m_id)           && 
	       other.m_name.equals(m_name)       &&
   	       other.m_unitPrice == m_unitPrice;
    }
}