/*
 * GUI.java
 *
 * Created on 17 August 2007
 *
 * The class that interacts with the user
 */

package loan;
import java.awt.*;
import java.awt.event.*;

/**
 *
 * @author merethe
 */
public class GUI extends Frame{
    Loan loan;
    static final int W_HEIGHT = 800;    //Window height
    static final int W_WIDTH = 600;     //Window width
    ActionListener buttonListener;
    TextField moneyInput;
    TextField yearsInput;
    TextArea resultArea;
    
    /** Creates a new instance of GUI */
    public GUI(Loan loan){
        this.loan = loan;
    }
    
    /**
     * Show the input boxes, calculate button and result area
     **/
    public void show_loan_input(){
        start_window();
        
        //Make the input panel
        Panel panel = new Panel();
        panel.setLayout(new FlowLayout(FlowLayout.LEFT));
        
        //Add money amount
        Label moneyLabel = new Label("Amount of money:");
        panel.add(moneyLabel);
        
        TextField moneyInput = new TextField();
        moneyInput.setColumns(10);
        panel.add(moneyInput);
        this.moneyInput = moneyInput;
        
        //Add number of years
        Label yearsLabel = new Label("Number of years:");
        panel.add(yearsLabel);
        
        TextField yearsInput = new TextField();
        yearsInput.setColumns(2);
        panel.add(yearsInput);
        this.yearsInput = yearsInput;
        
        //Add calculation button
        Button calcButton = new Button("Calculate");
        calcButton.addActionListener(this.buttonListener);
        panel.add(calcButton);
        

        //Make the text area panel
        Panel panel2 = new Panel();
        panel2.setLayout(new FlowLayout(FlowLayout.LEFT));
        
        resultArea = new TextArea(30, 90);
        panel2.add(resultArea);
                
        add(panel, BorderLayout.NORTH);
        add(panel2);
        
        end_window();
    }
    
    /**
     * Starts a window. This method must be called before a window is made
     */
    private void start_window(){
        //Listen to actions
        ActionListener buttonListener = new ActionListener(){
            public void actionPerformed(ActionEvent ae){
                String action = ae.getActionCommand();
                
                if(action.equals("Calculate")){
                    calculate();
                }
            }
        };
        
        this.buttonListener = buttonListener;
    }
    
    /**
     * Show the window and add closing mechanism.
     */
    private void end_window(){
        //Add closing mechanism
        addWindowListener(
            new WindowAdapter(){
                public void windowClosing(WindowEvent e){
                    System.exit(0);
                }
            }
        );
        
        setSize(W_HEIGHT, W_WIDTH);
        
        setVisible(true);
    }
    
    /**
     * Calculate and display the payment
     */
    private void calculate(){
        try{
            int money = Integer.parseInt(moneyInput.getText());
            loan.set_money(money);
            int years = Integer.parseInt(yearsInput.getText());
            loan.set_years(years);
        } catch(Exception e){
            //TODO: Should give an error message telling the user
            //to only write numbers
        }
        
        String results = loan.calculate();

        resultArea.setText(results);
    }
}