# polygon_edit.py

# polygon_edit.py

from Tkinter import *
#Tk()

import sys

root = Tk()
R = 10
p = []
history = []

def f_redraw():
    w.delete(ALL)
    for i in range(len(p)):
        j = (i + 1) % len(p)
        w.create_line(p[i][0], p[i][1], p[j][0], p[j][1], fill="red")
    # enumerate([x, y, z]) = [(0, x), (1, y), (2, z)]
    for i, (x, y) in enumerate(p):
        w.create_oval(x - R, y - R, x + R, y + R,
            fill="green", outline="#00aa00")
        w.create_text(x, y, fill="white",
            text=str(i+1), justify=CENTER, font="Courier 10 bold")

def f_key(event):
    c = repr(event.char)
    print("pressed key {0} {1}".format(c, event.char))
    if event.char == 'q':
        sys.exit(0)

def dist(a, b):
    return (a[0]-b[0])**2 + (a[1]-b[1])**2
def f_delete(event):
    print("clicked-2 at", event.x, event.y)
    global p
    if len(p) == 0:
        return
    pos = (event.x, event.y)
    i = 0
    for j in range(len(p)):
        if dist(pos, p[j]) < dist(pos, p[i]):
            i = j
    history.append(list(p))
    p = p[:i] + p[i+1:]
    f_redraw()

def f_cancel(event):
    global p, history
    print("cancel: len(history) = %d" % len(history))
    if len(history) > 0:
        p = history[-1]
        history = history[:-1]
    f_redraw()

def f_button(event):
    print("clicked-1 at", event.x, event.y)
    global R, history, p
    w.focus_set()
    history.append(list(p))
    p.append((event.x, event.y))
    f_redraw()

w = Canvas(root, width=400, height=400)
w.focus_set()
w.bind("<Key>", f_key)
w.bind("<Control-z>", f_cancel)
w.bind("<Control-Z>", f_cancel)
w.bind("<Button-1>", f_button)
w.bind("<Button-3>", f_delete)
w.pack()

root.mainloop()