#!/usr/bin/env python3

import re
from subprocess import Popen, PIPE
import pickle
import pytz
from datetime import datetime
from sys import argv

def cmd(*args):
    proc = Popen(args, stdout=PIPE)
    while True:
        line = proc.stdout.readline()
        if line:
            try:
                yield str(line[:-1], 'utf-8', 'ignore')
            except:
                pass
        else:
            break

data_file = '/home/zgrep/offtopiabday/timezone-offtopia.pickle'

def get_data():
    global data_file
    with open(data_file, 'rb') as fh:
        return pickle.load(fh)

def save_data(data):
    global data_file
    with open(data_file, 'wb') as fh:
        return pickle.dump(data, fh)

def get_time(n):
    nl = n.lower()
    data = get_data()
    if nl in data:
        tz = data[nl]
        return 'time(' + n + ') = ' + tz.fromutc(datetime.now()).strftime('%a, %Y-%m-%d %H:%M:%S %Z.')
    return n + '.tz = undefined'

def set_tz(n, s):
    data = get_data()
    nl = n.lower()
    try:
        tz = pytz.timezone(s)
    except pytz.exceptions.UnknownTimeZoneError:
        if s.lower() in ('none', 'false', 'delete', '', 'undefined'):
            if nl in data:
                del data[nl]
                save_data(data)
                return n + '.tz = undefined'
            return n + '.tz = undefined'
        return 'tz(' + s + ') = InvalidTimezone'
    except:
        return 'ERR: NaN IS A NUMBER.'
    data[nl] = tz
    save_data(data)
    return n + '.tz = ' + s + '; ' + get_time(n)

def main():
    if len(argv) == 3:
        print(get_time(argv[2]))
        exit()

    if len(argv) != 2:
        print('Usage:', argv[0], '#channel')
        exit(1)

    chan = '/home/zgrep/offtopiabday/irc.freenode.net/' + argv[1]

    for line in cmd('tail', '-n', '0', '-f', chan + '/out'):
        date, time, nick, line = line.split(' ', 3)
        nick = nick[1:-1]
        if nick in ('happybot', 'hatebot', '!', '-!-'):
            continue
        m = re.match(r'(?:@?(?:happybot|hatebot)[:,]? )?tz ?= ?(.+)$', line)
        if m:
            reply = set_tz(nick, m.group(1))
            with open(chan + '/in', 'w') as fh:
                fh.write(reply + '\n')
            continue
        for i, (r, o) in enumerate((
                (r'time\((\S+)\);?', True),
                (r'\(time (\S+)\)', True),
                (r'time\[(\S+)\];?', True),
                (r'(\S+)\.time', True),
                (r'time (\S+)', False)),
            ):
            m = r'@?(?:happy|hate)(bot)[:,]? '
            if o: m = r'(?:' + m + r')?'
            m = re.match(m + r + r'$', line)
            if m: break
        if m:
            reply = get_time(m.group(2))
            with open(chan + '/in', 'w') as fh:
                fh.write(nick + ': ' + reply + '\n')
            continue

if __name__ == '__main__':
    main()