#Project4 Dragon Curve Solution
# Josh Fuerst 10/10/12
#
# extended to generate dragon curve on th fly
# extended to do bracketed L0 systems
# Hoffmann October 2012
#
# coordinate system left native
#
from PIL import Image
from PIL import ImageDraw
import math
import random

# change heading by angle a, but
# keep headings between -180 and +180
# all angles in degrees as int
# reference direction is North
def adjState(xya, a):
    dr = xya[2]+a
    while dr > 180: dr -= 360
    while dr < -180: dr += 360
    return (xya[0], xya[1], dr)

# forward line drawn from current state and heading
# drw is the drawing object
# inverted y direction by using -length * cosine
def drawLineAngle(state, length, drw, color):
    x0 = state[0]
    y0 = state[1]
    dr = state[2]
    al = math.radians(dr)
    cs = math.cos(al)
    sn = math.sin(al)
    x1 = x0 + length*sn
    y1 = y0 - length*cs
    drw.line((x0,y0,int(x1),int(y1)),color)
    return (x1,y1,dr)

# interpret string for drawing
def mapDraw(str,img,gen,ang):
    state = (img.size[0]/2, img.size[1]/2, 0) # init turtle state
    stack = []
    drw = ImageDraw.Draw(img)
    if   gen<3: line = 20
    elif gen<4: line = 20
    elif gen<5: line = 10
    else:       line = 5
    #print('string arg', str)
    for ch in str:
        if ch == 'F':
            state = drawLineAngle(state,line,drw,(0,0,0))
        elif ch == '+':
            state = adjState(state, ang)
        elif ch == '-':
            state = adjState(state,-ang)
        elif ch == '[':
            stack.append(state)
        elif ch == ']':
            state = stack.pop()
        # else we ignore it
    #img.show()
    del drw

def rewrit(strng, ruleindex):
    L = []
    for ch in strng:
        if ch in rewrite[ruleindex]:
            L.append(rewrite[ruleindex][ch])
        else:
            L.append(ch)
    strng = "".join(x for x in L)
    print(strng)
    return strng
    
def Lsystem1(gen, img):
    # this is a fixed L-system, no generality
    strng = 'F'
    for g in range(gen):
        strng = rewrit(strng,0)
    mapDraw(strng,img,gen,22)
    return
    
def Lsystem2(gen, img):
    # this is a fixed L-system, no generality
    strng = 'FX'
    for g in range(gen):
        strng = rewrit(strng,1)
    mapDraw(strng,img,gen,90)
    return


def control():
    print("type command --")
    print("   0 - exit")
    print("   1 - grass")
    print("   2 - dragon")
    cmd = eval(input(":: "))
    if cmd != 0:
        gen = eval(input("generation: "))
        if gen<1: gen=1
        if gen>15: gen=15
    else:
        gen = 0
    return cmd, gen

# rewrite rules
rewrite = [{
        'F':'F[-F]F[+F][F]'
    }, {
        'X':'X+YF',
        'Y':'FX-Y'
    }]

def main():

    # launch dialogue
    c,g = control()
    while c > 0:
        if c > 3:
            break
        img = Image.new('RGB',(300,400),'white')
        if c==1:
            print("Lsys 1",g)
            Lsystem1(g, img)
            img.show()
            #img.save("Lsys_image_" + str(g) + ".jpeg")
        elif c == 2:
            print("Lsys 2",g)
            Lsystem2(g, img)
            img.show()
        else:
            print("done")
        c,g = control()
        #break
    print("image saved")
main()