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.")