// MoveCmd.java
// Command class to perform a move command.

// Written by THC for CS 5 Lab Assignment 3.

import java.awt.*;

public class MoveCmd extends Command {
  private Point lastPoint; // the mouse position last time
  private Shape s; // which Shape is being moved

  // When the mouse is pressed, find the frontmost Shape in the drawing
  // that contains the mouse position. If there is such a Shape, then
  // remember the Shape and the mouse position.
  public void executePress(Point p, Drawing dwg) {
    // Find the frontmost Shape containing p.
    s = dwg.getFrontmostContainer(p);

    if (s != null) // was there a Shape containing p?
      lastPoint = p; // yes, remember where p is
  }

  // When the mouse is dragged, if we had found a Shape when the mouse was
  // pressed, move the Shape by the difference between the current position of
  // the mouse and where it was last time. Then update so that the current
  // mouse position will be remembered for next time.
  public void executeDrag(Point p, Drawing dwg) {
    if (s != null) { // did we find a Shape when the mouse was pressed?
      s.move(p.x - lastPoint.x, p.y - lastPoint.y); // yes, so move it...
      lastPoint = p; // ...and remember current mouse position
    }
  }
}