#!/usr/bin/python3
"""Really simple hacky interactive UI for the Game of Life."""
import tkinter


import life

def main():
    tk = tkinter.Tk()
    tk.title("Life")
    w = tkinter.Canvas(tk, width=512, height=512, background='#f7f7f7')
    w.pack()
    scales = [32]
    boards = [{(8,7), (9,7), (7,8), (8,8), (8,9)}]  # Default to R-pentomino
    history = []
    origin = [(0, 0)]
    running = []

    def zoom(factor):
        scale, = scales
        newscale = scale * factor
        if newscale > 512: return
        scales[0] = newscale
        dx = 128//scale if factor > 1 else -128//newscale
        scroll(dx, dx)

    def redraw():
        w.delete(tkinter.ALL)
        scale, = scales
        margin = scale / 16
        for x, y in boards[0]:
            x0 = (x - origin[0][0]) * scale + margin
            y0 = (y - origin[0][1]) * scale + margin
            xmax = x0 + scale - margin
            ymax = y0 + scale - margin
            w.create_oval(x0, y0, xmax, ymax)

    def step(*a):
        history.append(boards[0])
        if len(history) > 1024:
            history.pop(0)
        boards[0] = life.succ(boards[0])
        redraw()

    def back(*a):
        if not history: return
        boards[0] = history.pop()
        w.after_idle(redraw)

    def run():
        if running:
            running[:] = []
            b.configure(text='Run')
        else:
            b.configure(text='Stop')
            running.append(1)
            keep_running()

    def keep_running():
        if running:
            step()
            tk.after(17, keep_running)

    def scroll(dx, dy):
        origin[0] = [origin[0][0] + dx, origin[0][1] + dy]
        redraw()

    b = tkinter.Button(tk, text='Run', command=run)
    s = tkinter.Button(tk, text='Step', command=step)
    back_b = tkinter.Button(tk, text='Back', command=back)
    zout = lambda *a: zoom(.5)
    zin = lambda *a: zoom(2)
    zout_b = tkinter.Button(tk, text='Zoom out', command=zout)
    zin_b = tkinter.Button(tk, text='Zoom in', command=zin)
    # XXX TODO scrollbars
    left =  lambda *a: scroll(-(256 // scales[0]), 0)
    up =    lambda *a: scroll(0, -(256 // scales[0]))
    down =  lambda *a: scroll(0, (256 // scales[0]))
    right = lambda *a: scroll(256 // scales[0], 0)
    left_b = tkinter.Button(tk, text='←', command=left)
    up_b = tkinter.Button(tk, text='↑', command=up)
    down_b = tkinter.Button(tk, text='↓', command=down)
    right_b = tkinter.Button(tk, text='→', command=right)
    for bi in b, s, back_b, zout_b, zin_b, left_b, up_b, down_b, right_b:
        bi.pack(side='left')

    def clicker(ev):
        scale, = scales
        bx = ev.x // scale + origin[0][0]
        by = ev.y // scale + origin[0][1]
        if (bx, by) in boards[0]:
            boards[0].remove((bx, by))
        else:
            boards[0].add((bx, by))
        w.focus_set()
        redraw()

    
    for k, v in {'<Button-1>': clicker,
                 '<Button-4>': zin,    '<plus>': zin,       '<KP_Add>': zin,
                 '<Button-5>': zout,  '<minus>': zout, '<KP_Subtract>': zout,
                 '<Left>':  left,   '<KP_Left>': left,
                 '<Right>': right, '<KP_Right>': right,
                 '<Up>':   up,     '<KP_Up>': up,  '<Prior>': up,  '<KP_Prior>': up,
                 '<Down>': down, '<KP_Down>': down, '<Next>': down, '<KP_Next>': down,
                 '<period>': step, '<BackSpace>': back,
    }.items():
        w.bind(k, v)
    w.focus_set()

    redraw()
    tkinter.mainloop()


if __name__ == '__main__':
    main()