import sys, subprocess, numpy, Gnuplot

latency_file = "latencies.txt"

def create_latency_file(logfile):
        # extract latency column from log
        out_file = open(latency_file, "w")
        var = subprocess.call(["cut", "-d", " ", "-f", "4", logfile], stdout=out_file)
        out_file.close()

def get_ordered_latencies():

        latencies = []
        valid_latencies = []

        with open(latency_file) as f:
                data = f.read()
                latencies = data.split("\n")
                latencies.pop(-1) #ninjahack

        for latency in latencies:
                # Only use valid latencies. -1 indicates failure
                if latency != '-1':
                        valid_latencies.append(float(latency))

        return sorted(valid_latencies)

def plot_cdf():
    x_values = get_ordered_latencies()
    y_values = numpy.arange(len(x_values))/float(len(x_values))

    gp = Gnuplot.Gnuplot(persist = 1)
    gp('set title "CDF of latencies"')
    gp('set grid')
    gp('set xlabel "Latency [s]"')
    gp('set ylabel "Cumulative probability"')

    cdf = Gnuplot.Data(x_values, y_values, with_="line", title="Latency")
    gp.plot(cdf)


if __name__ == "__main__":
    if len(sys.argv) == 2:
        if 'plot' in sys.argv[1]:
            print "... Plotting CDF ..."
            plot_cdf()
            print "... Plotting completed ..."
    elif len(sys.argv) == 3:
        if "extract" in sys.argv[1]:
            print "... Extracting latencies from logfile ..."
            create_latency_file(sys.argv[2])
            print "... Done ..."
    else:
        print "Commands:"
        print "* 'extract' 'logfile': creates a new file with all the latencies extracted from the log file"
        print "* 'plot': plots the latencies from the newly created latency file using Gnuplot"