# ------------------------------------
# Character Patterns
# ------------------------------------
def countDown(n):
    if n <= 0: # Base case
        pass
    else:
        # Act
        print(n)

        # Recurse
        countDown(n-1)

def tower(name):
    if len(name) == 0:  # Base case
        pass
    else:
        # Act
        print name

        # Recurse
        tower(name[1:])

def countDownUp(n):
    if n <= 0: # Base case
        pass
    else:
        # Act
        print n

        # Recurse
        countDownUp(n-1)

        # Act
        print n


# ------------------------------------
# Turtle patterns
# ------------------------------------
from turtle import *

def spiral(sideLen, angle, scaleFactor, minLength):

    if sideLen >= minLength:

        # Act
        fd(sideLen)

        # Setup
        lt(angle)

        # Recurse
        spiral(sideLen*scaleFactor, angle, scaleFactor, minLength)


def spiralBack(sideLen, angle, scaleFactor, minLength):

    if sideLen >= minLength:

        # Act
        fd(sideLen)

        # Setup
        lt(angle)

        # Recurse
        spiralBack(sideLen*scaleFactor, angle, scaleFactor, minLength) # Recurse

        # Invariate
        pu()
        rt(angle)
        bk(sideLen)
        pd()

# ------------------------------------
# Graphic Patterns
# ------------------------------------
from cs1graphics import *

def drawDisc(canvas, x, y, radius, color):
    ''' Helper function '''
    c = Circle(radius, Point(x,y))
    c.setFillColor(color)
    canvas.add(c)

def drawTarget(canvas, x, y, radius, thickness, color1, color2):
    if radius < thickness:  # Base case
        pass
    else:

        # Act
        drawDisc(canvas, x, y, radius, color1)

        # Recurse
        drawTarget(canvas, x, y, radius-thickness, thickness, color2,color1)  # Recurse

#paper = Canvas(650, 600, 'darkolivegreen', 'Bullseye')
#drawTarget(paper, 225, 225, 200, 10, 'purple', 'orange')
#paper.close()