/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package model;

import java.util.Observable;
import library.Converter;

/**
 *
 * @author cirstea
 */
public class Computer extends Observable {
    //    classic (not Observable)
    //    private List<View> listViews = null;
    // first operand
    private Integer operand;
    // second operand and repository for result
    private Integer result;
    // operation
    private int operation;

    public Computer() {
        //        classic (not Observable)
        //        listViews = new ArrayList<View>();
        this.operation = Converter.EQUAL;
    }

    public Integer getOperand() {
        return operand;
    }

    public void setOperand(Integer operand) {
        this.operand = operand;
    }

    public Integer getResult() {
        return result;
    }

    public void setResult(Integer result) {
        this.result = result;
    }

    public Integer getOperation() {
        return this.operation;
    }

//    public void addObserver(View view) {
//        listViews.add(view);
//    }

//    public void notifyView() {
//        for (View view : listViews) {
//            view.update();
//        }
//    }

    public void setOperand(int operand) {
        this.operand = operand;
        setChanged();
        notifyObservers(false);
    }

    public void setOperation(int operation) {
        Integer newResult;
        if (operand == null) {
            throw new RuntimeException("No operands");
        } else {
            switch (this.operation) {
                case Converter.PLUS:
                    newResult = result + operand;
                    break;
                case Converter.MINUS:
                    newResult = result - operand;
                    break;
                case Converter.EQUAL: // = or the very first operation
                    newResult = operand;
                    break;
                default: // never
                    newResult = Integer.MAX_VALUE;
            }
            operand = newResult;
            result = newResult;
            System.out.println("COMPUTER : " + newResult);
            this.operation = operation;
        }
        setChanged();
        notifyObservers(true);
    }
}