#!/usr/bin/env python3

# Fixup non existent time-zones. Some systems have time-zone set to: Los*
# (Los_Angeles), Den* (Denver), New* (New_York) ... but those are no real IANA
# assigned time zones. In the past they have been silently remapped.
#
# Time to clean it up!
#
# Migrate all configured timezones to real IANA assigned timezones!

import re
import sys

from vyos.configtree import ConfigTree
from vyos.util import cmd


if (len(sys.argv) < 1):
    print("Must specify file name!")
    sys.exit(1)

file_name = sys.argv[1]

with open(file_name, 'r') as f:
    config_file = f.read()

config = ConfigTree(config_file)
tz_base = ['system', 'time-zone']
if not config.exists(tz_base):
    # Nothing to do
    sys.exit(0)
else:
    tz = config.return_value(tz_base)

    # retrieve all valid timezones
    try:
        tz_datas = cmd('find /usr/share/zoneinfo/posix -type f -or -type l | sed -e s:/usr/share/zoneinfo/posix/::')
    except OSError:
        tz_datas = ''
    tz_data = tz_datas.split('\n')

    if re.match(r'[Ll][Oo][Ss].+', tz):
        tz = 'America/Los_Angeles'
    elif re.match(r'[Dd][Ee][Nn].+', tz):
        tz = 'America/Denver'
    elif re.match(r'[Hh][Oo][Nn][Oo].+', tz):
        tz = 'Pacific/Honolulu'
    elif re.match(r'[Nn][Ee][Ww].+', tz):
        tz = 'America/New_York'
    elif re.match(r'[Cc][Hh][Ii][Cc]*.+', tz):
        tz = 'America/Chicago'
    elif re.match(r'[Aa][Nn][Cc].+', tz):
        tz = 'America/Anchorage'
    elif re.match(r'[Pp][Hh][Oo].+', tz):
        tz = 'America/Phoenix'
    elif re.match(r'GMT(.+)?', tz):
        tz = 'Etc/' + tz
    elif tz not in tz_data:
        # assign default UTC timezone
        tz = 'UTC'

    # replace timezone data is required
    config.set(tz_base, value=tz)

    try:
        with open(file_name, 'w') as f:
            f.write(config.to_string())
    except OSError as e:
        print("Failed to save the modified config: {}".format(e))
        sys.exit(1)