import cmd
import threading
from queue import Empty, Queue
from equipment.turtle_device import TurtleDevice


class TurtleDeviceThread(threading.Thread):
    # TODO(Homework 4)
    def __init__(self):
        super().__init__()
        self.device = TurtleDevice()
        self.queue = Queue()

    def run(self):
        while True:
            try:
                item = self.queue.get()
            except self.queue.Empty:
                continue
            else:
                if (item == 'exit'):
                    break
                self.device.execute(item[0], item[1:])
                self.queue.task_done()             

class NoBlockingTurtleShell(cmd.Cmd):
    intro = 'Welcome to the turtle shell.   Type help or ? to list commands.\n'
    prompt = '(turtle) '
    file = None

    def __init__(self, turtle_thread: TurtleDeviceThread):
        super(NoBlockingTurtleShell, self).__init__()
        self.turtle_thread = TurtleDeviceThread()

    def do_execute(self, arg):
        self.turtle_thread.queue.put(arg)

    def do_exit(self, arg):
        self.turtle_thread.queue.put('exit')


if __name__ == '__main__':
    turtle_thread = TurtleDeviceThread()
    turtle_thread.start()
    NoBlockingTurtleShell(turtle_thread).cmdloop()