#!/usr/bin/env python3

'''
        TIME server, should respond to time requests of VMS, VAXELN en (soon) RSTS

$       open /read /write NETF ONAPI4::"150="
$       write NETF "''f$getsyi("SCSNODE")'"
$       read NETF time
$       close NETF

'''

import sys, json, socket
from datetime import datetime
from time import sleep

def main(argv):

    encode = json.JSONEncoder().encode
    decode = json.JSONDecoder().decode

    logreq = dict (level = 20, message = "Starting TIME server as object 150")
    print (encode(logreq), file = sys.stderr, flush = True)

    for work in sys.stdin:

        work = decode(work)

#    Each work item contains three standard fields:
#      handle - an integer that uniquely identifies a connection
#      type   - the type of data, for example "interrupt"
#      data   - the payload received (as a latin-1 encoded string,
#               which stands for the underlying bytes 1:1)

        conn  = work["handle"]
        mtype = work["type"]
        msg   = work["data"]

        if mtype == "data":

            logreq = dict (level = 20, message = "Data received: " + msg)
            print (encode(logreq), file = sys.stderr, flush = True)

            sleep(1)
            dn = datetime.now()

            if msg[:6] == 'PIRSTS':
                # send the local time in RSTS-format

                dateCode = (int(dn.strftime("%Y"))-1970)*1000+int(dn.strftime("%-j"))
                timeCode = 1440-int(dn.strftime("%-H"))*60-int(dn.strftime("%-M")) # minutes until midnight
                remtime = str(dateCode) + " " + str(timeCode)
            else:
                # send the local time in VMS-format
                remtime = dn.strftime("%d-%b-%Y %H:%M:%S.%f").upper()[:23]

            req = { "handle" : conn, "type" : "data", "data" : remtime }
            print (encode(req), flush = True)

            logreq = dict (level = 20, message = "Time sent: " + remtime)
            print (encode(logreq), file = sys.stderr, flush = True)

        elif mtype == "connect":

            logreq = dict (level = 20, message = "Connect request received.")
            print (encode(logreq), file = sys.stderr, flush = True)

            req = { "handle" : conn, "type" : "accept" }
            print (encode(req), flush = True)

            sleep(1)

        elif mtype == "disconnect":

            logreq = dict (level = 20, message = "Disconnect received.")
            print (encode(logreq), file = sys.stderr, flush = True)

            # Client connection is closed, exit
            return 0

    # Unexpected EOF on stdin without a preceding disconnect
    return 1

if __name__ == "__main__":
    sys.exit(main(sys.argv))