package interactors;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * The MoveInteractor computes the new top/left of a selected object and
 * passes that information to the start, running, and stop actions
 */

public class MoveInteractor extends Interactor {
    // leftOffset and topOffset represent the offset of the mouse cursor
    // from the upper left corner of the selected object when the mouse
    // is first pressed over the object
    int leftOffset;
    int topOffset;

    public MoveInteractor(int start, int stop) {
	super(start, stop);
    }

    // compute the initial offset of the mouse from the upper left corner
    // of the selected object so that the position of the cursor with respect
    // to the upper left corner is maintained throughout the move interaction
    public void mousePressed(MouseEvent e) {
	int x = e.getX();
	int y = e.getY();
	leftOffset = x - (int)selectedObj.getX();
	topOffset = y - (int)selectedObj.getY();
	startAction((int)selectedObj.getX(), (int)selectedObj.getY(), e);
    }
    
    public void mouseReleased(MouseEvent e) {
	stopAction(e.getX() - leftOffset, e.getY() - topOffset, e);
    }

    public void mouseDragged(MouseEvent e) {
	runningAction(e.getX() - leftOffset, e.getY() - topOffset, e);
    }

    public void startAction(int left, int top, MouseEvent e) { 
	// nothing to be done
    }

    public void runningAction(int left, int top, MouseEvent e) { 
	// mark both the old and new locations of the selected object as
	// being damaged
	JPanel parentPanel = (JPanel)e.getSource();
	parentPanel.repaint(selectedObj);
	selectedObj.setLocation(left, top);
	parentPanel.repaint(selectedObj);
    }

    public void stopAction(int left, int top, MouseEvent e) {
	// mark both the old and new locations of the selected object as
	// being damaged
	JPanel parentPanel = (JPanel)e.getSource();
	parentPanel.repaint(selectedObj);
	selectedObj.setLocation(left, top);
	parentPanel.repaint(selectedObj);
    }
}