# -*- 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 (v1.1.1)
#
# Revision: (v1.1)
#	- fix: pencolor: set before drawing instead of at beginning of A()/B()
#	- add: colors2 - RGB+YCM
#	- rename function as Sierpinski_Triangle()
#	- code clean up, rename sides as n_colors (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):
    # A(level,fwd)		# A=> 'B'-'A'-'B': bottom-left B first then top A, then bottom-right B
    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


def Tree(level, branch, x_root, y_root, fwd, angle, colors=colors2):

	import math as m

	if ( level <= 0 ):
		return "Done! with Tree Level(%d) Branch(%d)" % (level, branch)

	# configuration
	fwdScale = 0.8
	angScale = 0.75
	color = colors[(level+branch) % n_colors]

	# parameters for next level tree
	fwdNext = fwd*fwdScale
	angNext = angle*angScale

	# Left branch

	angleD = angle
	angleR = (angleD + 90) * m.pi/180.0			# adding 90deg since we are going north
	x_rootNext = x_root + fwd * m.cos(angleR)
	y_rootNext = y_root + fwd * m.sin(angleR)

	t.pencolor(color)
	gotoOrigin(x_root, y_root)
	t.left(angleD)
	t.forward(fwd)
	t.left(-angleD)

	Tree(level-1, -1, x_rootNext, y_rootNext, fwdNext, angNext, colors)

	# Middle branch

	angleD = 0
	angleR = (angleD + 90) * m.pi/180.0
	x_rootNext = x_root + fwd * m.cos(angleR)
	y_rootNext = y_root + fwd * m.sin(angleR)

	t.pencolor(color)
	gotoOrigin(x_root, y_root)
	# t.right(angleD)
	t.forward(fwd)
	# t.right(-angleD)

	Tree(level-1, 0, x_rootNext, y_rootNext, fwdNext, angNext, colors)

	# Right branch

	angleD = angle
	angleR = (- angleD + 90) * m.pi/180.0
	x_rootNext = x_root + fwd * m.cos(angleR)
	y_rootNext = y_root + fwd * m.sin(angleR)

	t.pencolor(color)
	gotoOrigin(x_root, y_root)
	t.right(angleD)
	t.forward(fwd)
	t.right(-angleD)

	Tree(level-1, +1, x_rootNext, y_rootNext, fwdNext, angNext, colors)

	print("Done! with Tree Level(%d) Branch(%d)" % (level, branch))
	return "Done! with Tree Level(%d) Branch(%d)" % (level, branch)

def drawTree(level=3, branch=0, x_root=0, y_root=0, fwd=5, angle=60, colors=colors2):

	len_root = fwd*2

	t.pencolor(colors[(level+branch) % n_colors])

	# t.mode("standard")	# ccw, heading East (0 deg)
	# t.home()		# goto(0,0), heading East

	gotoOrigin(x_root,y_root)
	t.left(90)
	t.forward(len_root)
	Tree(level, branch, x_root, y_root=y_root+len_root, fwd=fwd, angle=angle, colors=colors)
	t.right(90)		# resume angle for next drawTree()

#
# 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 (False):
		Sierpinski_Triangle(level=2, fwd=5)
		Sierpinski_Triangle(level=4, fwd=5)
		Sierpinski_Triangle(level=6, fwd=5)
		Sierpinski_Triangle(level=8, fwd=5)
	else:
		Sierpinski_Triangle(level=0, fwd=5)

	drawTree(level=4, branch=0, x_root=0, y_root=-100, fwd=50, angle=80, colors=colors2)
	drawTree(level=3, branch=0, x_root=200, y_root=-200, fwd=50, angle=80, colors=colors2)
	drawTree(level=5, branch=0, x_root=-180, y_root=-200, fwd=50, angle=80, colors=colors2)
	
	t1 = clock()
	return "Done! in %.2f Seconds" % (t1-t0)

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