# -*- encoding: big5 -*-
#
# OR, -*- coding: big5 -*- // seems fine
#
# Sierpinski Triangle
#
# Author:
#	Jing-Shin Chang
#
# Emails:
#	jshin@csie.ncnu.edu.tw // shin@nlp.csie.ncnu.edu.tw // shin.jsc@gmail.com
#
# Last Update:
#	2019/11/22 (v1.1.2)
#
# Revision: (v1.1)
#	- fix: pencolor: set before drawing instead of at beginning of A()/B()
#	- add: colors2 - RGB+YCM
#	- rename function as Sierpinski_Triangle()
#	- (v1.1.1) code clean up, rename sides as n_colors
#	- (v1.1.2) odd-numbered start with A(), even-numbeder with B() [prior to v1.1.1]
#
# References:
#	https://zh.wikipedia.org/wiki/%E8%AC%9D%E7%88%BE%E8%B3%93%E6%96%AF%E5%9F%BA%E4%B8%89%E8%A7%92%E5%BD%A2
#

"""
這條曲線以L系統來記述為：

變數: A , B
常數: + , -
公理: A
規則:
A → B-A-B
B → A+B+A
A,B ： 向前
- ： 左轉60°
+ ： 右轉60°
"""

#+1 from turtle import *		# including mainloop
#+2 
from turtle import Turtle, Screen, mainloop
from time import clock

# TURTLEDEMO:
#	- Globals related to other modules must be declared in main when included by TURTLEDEMO
#- t = Turtle()
#- wn = Screen()

#- wn.bgcolor("black")
#- t.speed(0)

# n_colors = 6

colors0 = ["yellow", "magenta", "yellow", "magenta", "yellow", "magenta"]
colors1 = ["yellow", "magenta", "red", "magenta", "blue", "magenta"]
colors2 = ["red", "yellow", "green", "cyan", "blue", "magenta"]
n_colors = len(colors2)

def gotoOrigin(x=0,y=0):
    t.penup()
    t.goto(x,y)
    t.pendown()

def Sierpinski_Triangle(level=10, fwd=50):
    if (level % 2 == 1):
        # odd-numbered
        A(level,fwd)		# A => 'B'-'A'-'B': bottom-left B first then top A, then bottom-right B
    else:
        # even-numbered
        B(level,fwd)		# B => 'A'+'B'+'A': bottom-left A first then top B, then bottom-right A

def A(level,fwd,colors = colors2):

    if ( level <= 0 ):
        return "Done! with Level A(%d)" % level

    # t.pencolor(colors[level % n_colors])		#x will be overwritten by A/B(level-1)

    B(level-1,fwd)

    t.pencolor(colors[level % n_colors])
    t.forward(fwd)
    t.left(60)
    print("f-",end='')

    A(level-1,fwd)

    t.pencolor(colors[level % n_colors])
    t.forward(fwd)
    t.left(60)
    print("f-",end='')

    B(level-1,fwd)

    print("\nDone! with Level A(%d)" % level)
    return "Done! with Level A(%d)" % level

def B(level,fwd,colors = colors2):

    if ( level <= 0 ):
        return "Done! with Level B(%d)" % level

    # t.pencolor(colors[level % n_colors])		#x will be overwritten by A/B(level-1)

    A(level-1,fwd)

    t.pencolor(colors[level % n_colors])
    t.forward(fwd)
    t.right(60)
    print("f+",end='')

    B(level-1,fwd)

    t.pencolor(colors[level % n_colors])
    t.forward(fwd)
    t.right(60)
    print("f+",end='')

    A(level-1,fwd)

    print("\nDone! with Level B(%d)" % level)
    return "Done! with Level B(%d)" % level

#
# Try different parameter passing options
#
def main():
	global t, wn

	t = Turtle()		# Global must be declared in main when included in TURTLEDEMO
	wn = Screen()
	wn.bgcolor("black")
	# wn.bgcolor("white")
	t.speed(0)		# doesn't look like speeding by this arg

	t0 = clock()

	gotoOrigin(-200,-100)
	t.hideturtle()

	#
	# Even-numbered levels [2,4,6,8] are increasingly larger with the same top A structure.
	# Odd-numbered levels have similar relationship (but in opposite orientation).
	#
	# Best demo level: 6
	#
	if (True):
		# Sierpinski_Triangle(level=1, fwd=5)
		Sierpinski_Triangle(level=2, fwd=5)
		Sierpinski_Triangle(level=3, fwd=5)
		Sierpinski_Triangle(level=4, fwd=5)
		Sierpinski_Triangle(level=5, fwd=5)
		Sierpinski_Triangle(level=6, fwd=5)
		# Sierpinski_Triangle(level=7, fwd=5)
		# Sierpinski_Triangle(level=8, fwd=5)
	else:
		Sierpinski_Triangle(level=6, fwd=5)
	
	t1 = clock()
	return "Done! in %.2f Seconds" % (t1-t0)

if __name__ == "__main__":
    msg = main()
    print(msg)
    mainloop()		# keep alive until closed by user
# FIN