# File for using Grove Relay (http://www.seeedstudio.com/wiki/Grove_-_Relay)

# NOTE: Relay is normally open. LED will illuminate when closed and you will hear a definitive click sound
from enum import Enum
from grovepi import grovepi

import logging


class RelayMode(Enum):
    on = 1
    off = 0


class Relay:
    def __init__(self, port, initial_position=RelayMode.off):
        """Constructor of a Relay instance

        :param int port: The port where is connected the relay
        :param RelayMode initial_position: The initial position. Should be an instance of RelayMode
        """
        self.port = port
        self.initial_position = initial_position
        grovepi.pinMode(self.port, "OUTPUT")

        # Write the initial position to the relay
        if initial_position == RelayMode.on:
            self.on()
        else:
            self.off()

    def on(self):
        """Function to put the relay on on mode"""
        RelayInterface(self.port).on()

    def off(self):
        """Function to put the relay on off mode"""
        RelayInterface(self.port).off()

    def __enter__(self):
        logging.info(
            'Relay on port {port} has started with mode {mode}'.format(
                port=self.port,
                mode=self.initial_position.name
            )
        )

        # We make accessible this relay instance
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        # Always turn off the relay before leaving
        self.off()

        logging.info('Relay on port {port_number} has finished'.format(port_number=self.port))


class RelayInterface:
    def __init__(self, port):
        self.port = port

    def on(self):
        """Function to put the relay on on mode"""
        logging.debug('Relay on port {port_number} is now on'.format(port_number=self.port))
        self.write(RelayMode.on)

    def off(self):
        """Function to put the relay on off mode"""
        logging.debug('Relay on port {port_number} is now off'.format(port_number=self.port))
        self.write(RelayMode.off)

    def write(self, mode):
        """Write the mode on the relay

        :param RelayMode mode: the mode to write
        :return:
        """
        grovepi.digitalWrite(self.port, mode.value)