#!/usr/bin/python
######################################################################
#
# Example parser for the JSON format history stats output of grpcurl
# for the gRPC service provided on a Starlink user terminal.
#
# Expects input as from the following command:
# grpcurl -plaintext -d {\"get_history\":{}} 192.168.100.1:9200 SpaceX.API.Device.Device/Handle
#
# This script examines the most recent samples from the history data
# and computes several different metrics related to packet loss. By
# default, it will print the results in CSV format.
#
######################################################################

import json
import datetime
import sys
import getopt

from itertools import chain

fArgError = False

try:
    opts, args = getopt.getopt(sys.argv[1:], "ahs:vH")
except getopt.GetoptError as err:
    print(str(err))
    fArgError = True

# Default to 1 hour worth of data samples.
parseSamples = 3600
fUsage = False
fVerbose = False
fParseAll = False
fHeader = False

if not fArgError:
    if len(args) > 1:
        fArgError = True
    else:
        for opt, arg in opts:
            if opt == "-a":
                fParseAll = True
            elif opt == "-h":
                fUsage = True
            elif opt == "-s":
                parseSamples = int(arg)
            elif opt == "-v":
                fVerbose = True
            elif opt == "-H":
                fHeader = True

if fUsage or fArgError:
    print("Usage: "+sys.argv[0]+" [options...] [<file>]")
    print("    where <file> is the file to parse, default: stdin")
    print("Options:")
    print("    -a: Parse all valid samples")
    print("    -h: Be helpful")
    print("    -s <num>: Parse <num> data samples, default: "+str(parseSamples))
    print("    -v: Be verbose")
    print("    -H: print CSV header instead of parsing file")
    sys.exit(1 if fArgError else 0)

if fHeader:
    print("datetimestamp_utc,samples,total_ping_drop,count_full_ping_drop,count_obstructed,total_obstructed_ping_drop,count_full_obstructed_ping_drop,count_unscheduled,total_unscheduled_ping_drop,count_full_unscheduled_ping_drop")
    sys.exit(0)

# Allow "-" to be specified as file for stdin.
if len(args) == 0 or args[0] == "-":
    jsonData = json.load(sys.stdin)
else:
    jsonFile = open(args[0])
    jsonData = json.load(jsonFile)
    jsonFile.close()

historyData = jsonData['dishGetHistory']

# 'current' is the count of data samples written to the ring buffer,
# irrespective of buffer wrap.
current = int(historyData['current'])
nSamples = len(historyData['popPingDropRate'])

if fVerbose:
    print("current:               " + str(current))
    print("All samples:           " + str(nSamples))

nSamples = min(nSamples,current)

if fVerbose:
    print("Valid samples:         " + str(nSamples))

# This is ring buffer offset, so both index to oldest data sample and
# index to next data sample after the newest one.
offset = current % nSamples

tot = 0
totOne = 0
totUnsched = 0
totUnschedD = 0
totUnschedOne = 0
totObstruct = 0
totObstructD = 0
totObstructOne = 0

if fParseAll or nSamples < parseSamples:
    parseSamples = nSamples

# Parse the most recent parseSamples-sized set of samples. This will
# iterate samples in order from oldest to newest, although that's not
# actually required for the current set of stats being computed below.
if parseSamples <= offset:
    sampleRange = range(offset - parseSamples, offset)
else:
    sampleRange = chain(range(nSamples + offset - parseSamples, nSamples), range(0, offset))

for i in sampleRange:
    d = historyData["popPingDropRate"][i]
    tot += d
    if d >= 1:
        totOne += d
    if not historyData["scheduled"][i]:
        totUnsched += 1
        totUnschedD += d
        if d >= 1:
            totUnschedOne += d
    if historyData["obstructed"][i]:
        totObstruct += 1
        totObstructD += d
        if d >= 1:
            totObstructOne += d

if fVerbose:
    print("Parsed samples:        " + str(parseSamples))
    print("Total ping drop:       " + str(tot))
    print("Count of drop == 1:    " + str(totOne))
    print("Obstructed:            " + str(totObstruct))
    print("Obstructed ping drop:  " + str(totObstructD))
    print("Obstructed drop == 1:  " + str(totObstructOne))
    print("Unscheduled:           " + str(totUnsched))
    print("Unscheduled ping drop: " + str(totUnschedD))
    print("Unscheduled drop == 1: " + str(totUnschedOne))
else:
    # NOTE: When changing data output format, also change the -H header printing above.
    print(datetime.datetime.utcnow().replace(microsecond=0).isoformat()+","+str(parseSamples)+","+str(tot)+","+str(totOne)+","+str(totObstruct)+","+str(totObstructD)+","+str(totObstructOne)+","+str(totUnsched)+","+str(totUnschedD)+","+str(totUnschedOne))