import threading
import time
from datetime import datetime
from enum import Enum

from circuitbreaker import circuit

# Default switching time in seconds
SWITCHING_TIME = 120
# Scale speed of switching by factor x
SCALING = 100


class TrafficLight:
    class Color(Enum):
        GREEN = 0
        RED = 1

    # id of traffic light
    tlid: str
    # time between switches in seconds
    switching_time: int
    # timestamp of last switch
    last_switch: datetime
    # currently lit color
    current_color: Color
    # marks if traffic light started
    running: bool = False
    # stores starting color
    _starting_color: Color
    # stores runner thread
    _t: threading.Thread

    def __init__(self,
                 tlid: str,
                 switching_time: int = SWITCHING_TIME,
                 starting_color: Color = Color.RED):
        self.tlid = tlid
        self.switching_time = switching_time
        self._starting_color = starting_color

    def start(self):
        self.running = True

        def switcher():
            num_colors = len(self.Color)
            # set current color to the one before starting color, because switch immediately happens in loop
            # therefore it sleeps on the end of the loop and first status is immediately sent to msg broker
            self.current_color = TrafficLight.Color((self._starting_color.value - 1) % num_colors)
            while self.running:
                self.current_color = TrafficLight.Color((self.current_color.value + 1) % num_colors)
                self.last_switch = datetime.now()
                self.send_status_update()
                time.sleep(self.switching_time / SCALING)

        self._t = threading.Thread(target=switcher)
        self._t.start()

    def stop(self):
        self.running = False

    @circuit(failure_threshold=10, expected_exception=ConnectionError)
    def send_status_update(self):
        # TODO inform the message broker about the current status
        print(self.tlid, self.current_color, self.last_switch)


if __name__ == '__main__':
    tl1 = TrafficLight(tlid='tl1')
    tl1.start()