class CameraCommander:
	class InvalidStateException(Exception):
		pass


	Cameras = []


	def Register(context, camera):
		for c in CameraCommander.Cameras:
			if c.camera.id == camera.id:
				print("[CameraCommander] : Camera ({}) already registered".format(camera.id))
				raise CameraCommander.InvalidStateException()
		CameraCommander.Cameras.append(context)
		print("[CameraCommander] : Camera ({}) registered".format(camera.id))


	def GetContext(camera):
		for c in CameraCommander.Cameras:
			if c.camera.id == camera.id:
				return c
		return None


	def IsRegistered(context):
		return context in CameraCommander.Cameras


	def Remove(context):
		CameraCommander.Cameras.remove(context)
		print("[CameraCommander] : Camera ({}) unregistered".format(context.camera.id))