#!/usr/bin/env python
'''
ntpshmviz - graph the drift of NTP servers
Written by Keane Wolter <daemoneye2@gmail.com>
'''
#
# To do:
#
# 1. Add exit button so the user does not need to do <Ctrl>-w
# 2. Allow for a continuous stream of data to be graphed
#
# This file is Copyright (c) 2010-2018 by the GPSD project
# SPDX-License-Identifier: BSD-2-clause

from __future__ import absolute_import, print_function, division

import sys
# need numpy for float128, normal python floats are too small to
# hold a timespec
import numpy
try:
    import matplotlib.pyplot as PLT
except ImportError:
    print("Please make sure matplotlib is installed properly:",
          sys.exc_info()[0])
    sys.exit(1)

gps_version = '3.19-dev'


class ntpOffset(object):
    "The master Class"

    def __init__(self, stream):
        "Initialize class ntpOffset"

        # get the data
        self.read_data(stream)

        # display the data
        self.display()

    def display(self):
        "display the graphs"

        # Alert the user that closing the graphs can be done with "Ctrl-w"
        print ("Please note that the graph can be closed with the "
               "key combination of <Ctrl-w>")

        PLT.figure()
        subplot_value = 211
        for ntp_item in self.ntp_data:
            # create the subplot for the data
            PLT.subplot(subplot_value)
            # setup and create the vlines graph
            t = numpy.arange(0, self.line_counts[ntp_item], 1)
            PLT.vlines(t, 0, self.ntp_data[ntp_item], color='r')
            # add labels
            PLT.title("NTP drift for " + ntp_item)
            PLT.xlabel('sample')
            PLT.ylabel('drift')
            # increment the subplot by 1.
            # this allows for each data group to have it's own graph
            subplot_value += 1

        # make sure there is no graph or data overlapping each other and
        # display the graph
        PLT.tight_layout()
        PLT.show()

    def read_data(self, stream):
        "Read data from a ntp log file."

        # Layout is:
        #
        #   - The keyword "sample"
        #   - The NTP unit from which it was collected.
        #   - Collection time of day, expressed in seconds
        #   - Receiver time of day, expressed in seconds
        #   - Clock time of day, expressed in seconds
        #   - Leep-second notification status
        #   - Source precision (log(2) of source jitter)

        self.ntp_data = {}      # data sets for each ntp unit
        self.line_counts = {}   # Count of total lines for each ntp unit
        record = []             # A single record in the file or data stream
        offset = 0              # offset value to add to the array
        self.lines = 0          # width of graph

        for line in stream:
            if len(line.split(' ')) > 6:
                if line[:1] != '#':
                    line = line.lstrip()
                    record = line.split(' ')
                    try:
                        offset = (numpy.longdouble(record[3]) -
                                  numpy.longdouble(record[4]))
                    except:
                        print ("Invalid data: ", sys.exc_info()[0],
                               ". Data was: ", line)
                        continue

                    # If the NTP unit is in the dictionary
                    # append the offset to the list
                    # Otherwise, create a new list in the dictionary
                    # and add the offset.
                    if record[1] not in self.ntp_data:
                        self.ntp_data[record[1]] = []
                        self.line_counts[record[1]] = 0

                    self.ntp_data[record[1]].append(offset)
                    self.line_counts[record[1]] += 1
        stream.close()


if __name__ == "__main__":
    if len(sys.argv) >= 2:
        if (sys.argv[1] == "-V" or sys.argv[1] == "--version"):
            sys.stderr.write("ntpshmviz: Version %s\n" % gps_version)
            sys.exit(0)

        if (sys.argv[1] == "-h" or sys.argv[1] == "--help"):
            print("""
Usage: <input stream> | ntpshmviz [-h|--help] [-V|--version]

Example: ntpshmmon -n 100 | ntpshmviz

Options:
\t-h: help message
\t-V: version information

Report ntpshmviz bugs to Keane Wolter, daemoneye2@gmail.com
                      or gpsd-users@nongnu.org
gpsd homepage: www.catb.org/gpsd/
""")
            sys.exit()

    ntpOffset(sys.stdin)
    sys.exit()