#!/usr/bin/env python

program = 'vdifspec'
author  = 'Walter Brisken'
version = '0.3'
verdate = '20160610'

from os import system
from string import split
from sys import exit, argv


def usage():
	print '\n%s ver. %s  %s  %s\n' % (program, version, author, verdate)
	print 'A VDIF spectrometer for multi-thread VDIF data.  Uses vmux'
	print 'and m5spec to do the heavy lifting.\n'
	print 'Usage : %s <infile> <frame size> <data rate> <threadlist> <nchan> <nint> <outfile> [nbit] [<offset>]\n' % program
	print '  <infile> is the name of the VDIF file\n'
	print '  <frame size> is the size of each input VDIF frame, inc. header (e.g., 5032)\n'
	print '  <data rate> is the stream data rate (Mbps)\n'
	print '  <nchan> is the number of spectral channels to make per baseband channel\n'
	print '  <nint> is the number of FFT frames to spectrometize\n'
	print '  <outfile> is the name of the output file\n'
	print '  <nbit> is number of bits per sample (default is 2)\n'
	print '  <offset> optionally jump into input file by this many bytes\n'
	print 'Note: Only works on 2-bit real data for now...\n'

if len(argv) < 8:
	usage()
	exit()

infile = argv[1]
framesize = int(argv[2])
datarate = int(argv[3])
threadlist = argv[4]
nt = len(split(threadlist, ','))
nchan = int(argv[5])
nint = int(argv[6])
outfile = argv[7]
if len(argv) > 8:
	nbit = int(argv[8])
else:
	nbit = 2
if len(argv) > 9:
	offset = int(argv[9])
else:
	offset = 0

nc = 1
while(nc < nt):
	nc *= 2

outputpayload = nc*(framesize-32)
framespersecond = (datarate*1000000)/(nt*(framesize-32)*8)
outputdatarate = outputpayload*framespersecond*8/1000000

cmd = 'vmux %s %d %d %s - %d | m5spec - VDIF_%d-%d-%d-%d %d %d %s' % (infile, framesize, framespersecond, threadlist, offset, outputpayload, outputdatarate, nc, nbit, nchan, nint, outfile) 

print 'Executing: %s' % cmd
system(cmd)