#!/usr/bin/env python3
from tkinter import *
from tkinter import ttk

# --------------------------
# Model
# --------------------------
class DoubleLight:
    def __init__(self):
        self.l1 = 1
        self.l2 = 0
        
    def switch(self):
        if self.l1 == 1:
            self.set_l2()
        else:
            self.set_l1()
            
    def set_l1(self):
        self.l1 = 1
        self.l2 = 0
        
    def set_l2(self):
        self.l1 = 0
        self.l2 = 1
            
    def print_status(self):
        print("l1: " + str(self.l1) + "| l2: " + str(self.l2))
        
    def get_active(self):
        if self.l1 == 1:
            return 1
        else:
            return 2
    
# --------------------------
# Controller
# --------------------------
class TwoLightsController:
    def __init__(self, app):
        self.app = app
        self.lights = DoubleLight()
        
    def switch_lights(self, event=None):
        self.lights.switch()
        self.update_view()
        
    def update_view(self):
        active_light = self.lights.get_active()
        self.app.change_light_display(active_light)

# --------------------------
# View / Main Application
# --------------------------
class TwoLightsApp(Tk):
    def __init__(self):
        super().__init__()
        self.controller = TwoLightsController(self)
        
        self.color1 = "dark green"
        self.color2 = "green yellow"
        
        self.create_widgets()
        self.create_lights(self.color1)
        self.bind_events()
        
    def create_widgets(self):
        mainframe = ttk.Frame(self, padding="3 3 3 3")
        mainframe.grid(column=0, row=0, sticky=N+W+S+E)
        self.columnconfigure(0, weight=1)
        self.rowconfigure(0, weight=1)
        button_switch = ttk.Button(mainframe, text="Schalte um", command=self.controller.switch_lights)
        button_switch.grid(column=0, row=0, sticky=W)
        light_canvas = Canvas(mainframe, width=50, height=50, background="black")
        light_canvas.grid(column=1, row=0, sticky=W)
        self.lc = light_canvas
        
    def create_lights(self, color="dark green"):
        self.light1 = self.lc.create_rectangle(5,5,25,45,fill=color)
        self.light2 = self.lc.create_rectangle(25,5,45,45,fill=color)
        self.controller.update_view()
        
    def bind_events(self):
        self.bind("<Return>", self.controller.switch_lights)
    
    def change_light_display(self, active_light):
        if active_light == 1:
            self.lc.itemconfig(self.light1, fill=self.color2)
            self.lc.itemconfig(self.light2, fill=self.color1)
        else:
            self.lc.itemconfig(self.light1, fill=self.color1)
            self.lc.itemconfig(self.light2, fill=self.color2)
        
# --------------------------
# Execution
# --------------------------
if __name__ == "__main__":
    app = TwoLightsApp()
    app.mainloop()