#import Adafruit_GPIO as GPIO
#import Adafruit_GPIO.SPI as SPI

class ADS7952(object):
    """Class to represent an ADS 7952 analog to digital onverter."""

    def __init__(self, clk=None, cs=None, miso=None, mosi=None, spi=None, gpio=None):

        """Initialize MAX31855 device with software SPI on the specified CLK, CS, and DO pins.  Alternatively can specify hardware SPI by sending an Adafruit_GPIO.SPI.SpiDev device in the spi parameter."""

        self._spi = None
        # Handle hardware SPI
        if spi is not None:
            self._spi = spi
        elif clk is not None and cs is not None and miso is not None and mosi is not None:
            # Default to platform GPIO if not provided.
            if gpio is None:
                gpio = GPIO.get_platform_gpio()
                self._spi = SPI.BitBang(gpio, clk, mosi, miso, cs)
        else:
            raise ValueError('Must specify either spi for for hardware SPI or clk, cs, miso, and mosi for softwrare SPI!')
                # Set SPI clock in Hz
        self._spi.set_clock_hz(500000)
        self._spi.set_mode(0)
        self._spi.set_bit_order(SPI.MSBFIRST)

    def read_adc(self, adc_number):
        """Read the current value of the specified ADC channel (0-11).  The values can range from 0 to 4095 (12-bits)."""

        # Setting Auto-1 mode
        command = 0b0100000000000001                    
        resp = self._spi.transfer([command, 0x0, 0x0])  #send to SPI bus
        command = 0b1001001011000000					
        resp = self._spi.transfer([command, 0x0, 0x0])  
        command = 0b0010110000010001                    #set Auto-1 mode
        resp = self._spi.transfer([command, 0x0, 0x0])
        assert 0 <= adc_number <= 11, 'ADC number must be a value of 0-11!'
        command = 0b0000000000000000                    #remain in Auto-1 mode
        resp = self._spi.transfer([command, 0x0, 0x0])
        
        # Parse out the 12 bits of response data and return it.
        result = (resp[0] & 0x01) << 11
        result |= resp[1] >> 3
        result |= resp[2] >> 5
        return (result & 0x0FFF)