from cs1graphics import *

class ShapeHandler(EventHandler):
    def __init__(self):
        EventHandler.__init__(self)
        self._mouseDragged = False

    def handle(self, event):
        shape = event.getTrigger( )
        if event.getDescription( ) == 'mouse drag':
            old = event.getOldMouseLocation( )
            new = event.getMouseLocation( )
            shape.move(new.getX( ) - old.getX( ), new.getY( ) - old.getY( ))
            self._mouseDragged = True
        elif event.getDescription( ) == 'mouse click':
            self._mouseDragged = False
        elif event.getDescription( ) == 'mouse release':
            if not self._mouseDragged:
                shape.scale(1.5)
        elif event.getDescription( ) == 'keyboard':
            shape.setFillColor(Color.randomColor( ))

class NewShapeHandler(EventHandler):
    def __init__(self):
        EventHandler.__init__(self)
        self._shapeCode = 0
        self._handler = ShapeHandler( ) # single instance handles all shapes

    def handle(self, event):
        if event.getDescription( ) == 'mouse click':
            if self._shapeCode == 0:
                s = Circle(10)
            elif self._shapeCode == 1:
                s = Square(10)
            elif self._shapeCode == 2:
                s = Rectangle(15,5)
            elif self._shapeCode == 3:
                s = Polygon(Point(5,5),Point(0,-5),Point(-5,5))
            self._shapeCode = (self._shapeCode + 1) % 4 # advance cyclically

        s.move(event.getMouseLocation( ).getX( ), event.getMouseLocation( ).getY( ))
        s.setFillColor('white')
        event.getTrigger( ).add(s) # add shape to the underlying canvas
        s.addHandler(self._handler) # register the ShapeHandler with the new shape

def main():
    paper = Canvas(700, 600, 'light yellow', 'Click me!')

    # instantiate handler and register all at once
    paper.addHandler(NewShapeHandler( ))