import sys
import os

NUMBER_OF_CHANNELS = 16
SAMPLE_LENGTH = NUMBER_OF_CHANNELS // 8

def getBit(byteArray, bitNumber):
    "This returns bit with bitNumber position from byteArray"
    byte = byteArray[bitNumber // 8]
    return (byte >> (bitNumber % 8)) & 1

try:
    if len(sys.argv) < 2:
        raise ValueError('Too few input arguments.')

    sampleCounter = 0
    inputFileName = sys.argv[1]
    outputDirName = os.path.splitext(inputFileName)[0]

    inputFileSize = os.path.getsize(inputFileName)
    if inputFileSize % SAMPLE_LENGTH != 0:
        raise ValueError('Input file has wrong length.')

    try:
        inputFile = open(inputFileName, 'rb')
        outputFiles = []

        if not os.path.exists(outputDirName):
            os.mkdir(outputDirName)

        for channel in range(0, NUMBER_OF_CHANNELS):
            outputFiles.append(open(outputDirName + "/" + str(channel) + ".dat", 'w'))

        while True:
            multiChannelSample = inputFile.read(SAMPLE_LENGTH)
            if multiChannelSample == b'':
                break

            for channel in range(0, NUMBER_OF_CHANNELS):
                singleChannelSample = '+1' if (getBit(multiChannelSample, channel)) else '-1'
                outputFiles[channel].write(singleChannelSample + '\n')

            sampleCounter += 1

    finally:
        inputFile.close()
        for channel in range(0, NUMBER_OF_CHANNELS):
            outputFiles[channel].close()

    print(str(sampleCounter), " samples were processed.\n")

except IOError as error:
    print(error, "\n")

except ValueError as error:
    print(error, "\n")

input("Press ENTER to quit.")