#!/usr/bin/python
# pytz-date.py - print current UTC, zoneinfo and pytz date time
#                in optional format "+"$1 in zone $#

from datetime import datetime
from zoneinfo import ZoneInfo
from pytz import timezone
import pytz
import sys
import os

TZ          = "TZ"                      # env var
GMT         = "GMT"                     # ref zones
GMTP0       = "GMT+0"
GMTM0       = "GMT-0"
UTC         = "UTC"
refs        = [ UTC , GMT , GMTP0 , GMTM0 ]
FMT         = "%c %Z%z"
zi_fmt      = "%tzoneinfo%t"
pytz_fmt    = "%tpytz%t%t"

dt_fmt      = FMT
tz          = os.getenv( TZ, UTC)       # TZ env var else UTC
argc        = len( sys.argv )
argn        = 1

# $1 +fmt optional override
if argc > argn and sys.argv[argn][0] == "+":
    dt_fmt  = sys.argv[argn][1:]
    argn   += 1

# $# zone
if argc > argn:
    tz  = sys.argv[argn]

# zone ref UTC
zones = [ UTC ]
# add arg if not same as ref
if tz not in refs:
    zones = zones + [ tz ]

# print ref and arg with zoneinfo and pytz
for z in zones:
# TZ=z  date    +"f" - zoneinfo
        print( datetime.now( ZoneInfo( z )).strftime( dt_fmt + zi_fmt + z ))
# TZ=z  date    +"f" - pytz
        print( datetime.now().astimezone( timezone( z )).strftime( dt_fmt + pytz_fmt + z ))