from enum import Enum
from xml_reader import Xml_reader
import RPi.GPIO as GPIO

class interface_handler:
    """handles the access to the various interfaces (e.g. GPIO)
    """

    class Pin(Enum):
        """list of all usable pins

        enables restricting methods to these pins
        """
        GIO_2 = 3
        GIO_3 = 5
        GIO_4 = 7
        GIO_5 = 29
        GIO_6 = 31
        GIO_7 = 26
        GIO_8 = 24
        GIO_9 = 21
        GIO_10 = 19
        GIO_11 = 23
        GIO_12 = 32
        GIO_13 = 33
        GIO_14 = 8
        GIO_15 = 10
        GIO_16 = 36
        GIO_17 = 11
        GIO_18 = 12
        GIO_19 = 35
        GIO_20 = 38
        GIO_21 = 40
        GIO_22 = 15
        GIO_23 = 16
        GIO_24 = 18
        GIO_25 = 22
        GIO_26 = 37
        GIO_27 = 13

    def __init__(self, xml_reader):
        """inits the interface_handler
        """
        if not isinstance(xml_reader, Xml_reader):
            raise TypeError('xml_reader must be an instance of XML_reader')
        self.xml_reader = xml_reader
        self.init_gpio()

    def init_gpio(self):
        """initialises the GPIO pins
        """
        GPIO.setmode(GPIO.BOARD)
        for device_name in self.xml_reader.get_device_names():
            protocol, pins in self.xml_reader.get_port(device_name)
            for pin in pins:
                if protocol == "AI" or "DI":
                    GPIO.setup(self.Pin(pin),GPIO.IN)
                elif protocol == "AO" or "DO":
                    GPIO.setup(self.Pin(pin),GPIO.OUT)
                else:
                    raise NotImplementedError('the protocol of the device %s is not implemented' % device_name)
                

    def read(self, device_name):
        """reads the current value from the pins of one device

        Args:
            device_name (string): the name of the device

        Raises:
            NameError: the device cannot be found in the config.xml

        Returns:
            dict:  {'pin': 'value'}
        """
        if self.xml_reader.get_port(device_name) == None:
            raise NameError('the device with the name %s is unknown' % device_name)
        returnValues = dict()
        protocol, pins = self.xml_reader.get_port(device_name)
        if not protocol == "AI" or "DI":
            raise ValueError("you can not read from device %s" % device_name)
        for pin in self.xml_reader.get_port(device_name)["pins"]:
            returnValues.update({
                pin,
                GPIO.read(self.Pin(pin))
            })
        return returnValues

    def write(self, device_name, value):
        """writes a value to all the pins of a device

        Args:
            device_name (string): name of the device 
            value (float): the value to be written

        Raises:
            NameError: device not found in config.xml
            TypeError: value has wrong type
        """
        if self.xml_reader.get_port(device_name) == None:
            raise NameError('the device with the name %s is unknown' % device_name)
        if not isinstance(value,float):
            raise TypeError('the value to write must be of type float')
        protocol, pins = self.xml_reader.get_port(device_name)
        if not protocol == "AO" or "DO":
            raise ValueError("you cannot write to device %s" % device_name)
        for pin in self.xml_reader.get_port(device_name)["pins"]:
            GPIO.write(self.Pin(pin,value))