'''
    GPIO module to handle the gpios on our beertap.
'''

import time
import RPi.GPIO as gpio

class GPIOHandler:
    '''
        Class which takes care of handling the gpio pins.
    '''

    # constants for syntactical purposes
    S_ON = gpio.LOW
    S_OFF = gpio.HIGH

    # gpio list
    gpio_list=[]

    def __init__(self, gpio_list):
        '''
            Contructor which takes a list of gpio pins
            and sets them all up to be used as output.
        '''
        for pin in gpio_list:
            self.gpio_list.append(pin)
            self.__setup_gpio(pin)

    def __set_gpio(self, channel=1, value=0):
        '''
            Try to safely change the value of a given gpio
            and cleanup in case of an error.
        '''
        try:
            gpio.output(channel, value)
        except:
            print("GPIO Error")
            gpio.cleanup()

    def __setup_gpio(self, channel=1):
        '''
            Takes a gpio channel, sets it to output mode
            and set gpio mode to BCM.
        '''
        print(f"setting up gpio_{channel}")
        gpio.setwarnings(False)
        gpio.setmode(gpio.BCM)
        gpio.setup(channel, gpio.OUT)
        self.__set_gpio(channel, self.S_OFF)

    def gpio_test(self):
        '''
            Test all configured channels
        '''
        for pin in self.gpio_list:
            self.__set_gpio(pin, self.S_ON)
            print(f"gpio_{pin}: on")
            time.sleep(0.1)
            self.__set_gpio(pin, self.S_OFF)
            print(f"gpio_{pin}: off")
            time.sleep(0.1)

    def gpio_set_pulse(self, channel=1, time_on=1):
        '''
            Sets the state of a given gpio pin to ON for a given amount of time
            then toggels it back to the previous state.
        '''
        self.__set_gpio(channel, self.S_ON)
        time.sleep(time_on)
        self.__set_gpio(channel, self.S_OFF)