import pickle
import threading
import time
from datetime import datetime

from circuitbreaker import circuit

# Default switching time in seconds
from shared import TrafficLightColor
from shared.TrafficLightColor import Color
from shared.message_broker_wrapper import MBWrapper

SWITCHING_TIME = 120
# Scale speed of switching by factor x
SCALING = 100


class TrafficLight:
    # 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

    # outgoing traffic light state MBWrapper
    _tl_mb: MBWrapper

    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

        self._tl_mb = MBWrapper(exchange_name='traffic_light_state_{}'.format(self.tlid))
        self._tl_mb.setup_sender()

    def start(self):
        self.running = True

        def switcher():
            num_colors = len(TrafficLightColor.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 = Color((self._starting_color.value - 1) % num_colors)
            while self.running:
                self.current_color = 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):
        print(self.tlid, self.current_color, self.last_switch)
        self._tl_mb.send(pickle.dumps({
            'tlid': self.tlid,
            'color': self.current_color,
            'last_switch': self.last_switch
        }))


if __name__ == '__main__':
    # TODO fetch and use data from Entity Ident

    tl1 = TrafficLight(tlid='traffic-light-1', switching_time=120)
    tl1.start()

    time.sleep(1)
    tl2 = TrafficLight(tlid='traffic-light-2', switching_time=240)
    tl2.start()

    time.sleep(1)
    tl3 = TrafficLight(tlid='traffic-light-3', switching_time=360)
    tl3.start()