#! /usr/bin/env python

## a text-terminal version of the WatchCheck app
## to track error, daily error rate of timepieces.

#
import time
import datetime
import json



def watch_stat():

    try:
        saved_error = open('error_list.json')
        error_list = json.load(saved_error)
    except:
        error_list = []




    if len(error_list) > 1:
        first_record = error_list[0]
        latest_record = error_list[-1]
        previous_record = error_list[-2]

        first_time = first_record[0]

        first_delta = first_record[1]

        latest_time = latest_record[0] 
        latest_delta = latest_record[1]

        previous_time = previous_record[0]
        previous_delta = previous_record[1]

        FMT = '%Y/%m/%d %H:%M:%S'
    
        t_latest = datetime.datetime.strptime(latest_time, FMT)
        t_previous = datetime.datetime.strptime(previous_time, FMT)
        t_first = datetime.datetime.strptime(first_time, FMT)

        tdelta = t_latest - t_previous
        full_delta = t_latest - t_first

        elapsed_time = tdelta.total_seconds()

        full_time = full_delta.total_seconds()

        print "First record time ", first_time
        print "First record delta ", first_delta
        print ""

        print "Previous record time ", previous_time
        print "Previous record delta ", previous_delta
        print ""

        print "Latest record time " , latest_time
        print "Latest record delta ", latest_delta
        print ""
    
        print "Overall elapsed time ", full_delta
        print "Latest elapsed time ", tdelta
        print ""

        # Current Error rate
        time_error = latest_delta - previous_delta
        error_rate = time_error / elapsed_time
        daily_rate = error_rate * (60*60*24)
        ppm_daily = error_rate * 1000000

        # Overall Error rate
        total_error = latest_delta - first_delta
        average_error_rate = total_error / full_time

        average_rate = average_error_rate * (60*60*24)
        ppm_overall = average_error_rate * 1000000


        print "Latest delta change ", time_error

        print "Latest elapsed time %d seconds " % (elapsed_time)

        print ""
        print "Daily PPM : %0.3f" % ppm_daily
        print "Daily rate error: %0.1f s/d " % (daily_rate)

        print ""
        print "Total Time %d seconds" % (full_time)
        print "Total error ", total_error
        print "Total PPM : %0.3f" % ppm_overall
        print "Total rate error: %0.1f s/d" % (average_rate)
        print ""
        print "========================================================"
        print " Delta : %0.1f s | Rate : %0.1f s/d | Average : %0.1f s/d" % (latest_delta, daily_rate, average_rate)
        print "========================================================"
        print ""
    else:
        print "No rate yet"


watch_stat()