#!/usr/bin/env python

import os, sys, re, json, datetime, optparse
import syslog

# boilerplate
basedir = os.path.abspath(os.path.join(os.path.dirname(__file__), "../.."))
sys.path = [ basedir ] + sys.path
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "ietf.settings")

import django
django.setup()

from django.conf import settings
from optparse import OptionParser

parser = OptionParser()
parser.add_option("-f", "--from", dest="start",
                  help="Start time, defaults to a little less than 23 hours ago", metavar="YYYY-MM-DD HH:MM:SS")
parser.add_option("-t", "--to", dest="end",
                  help="End time, defaults to 23 hours later than from", metavar="YYYY-MM-DD HH:MM:SS")
parser.add_option("", "--no-email", dest="send_email", default=True, action="store_false",
                  help="Skip sending emails")

options, args = parser.parse_args()

# compensate to avoid we ask for something that happened now and then
# don't get it back because our request interval is slightly off
CLOCK_SKEW_COMPENSATION = 5 # seconds

# actually the interface accepts 24 hours, but then we get into
# trouble with daylights savings - meh
MAX_INTERVAL_ACCEPTED_BY_IANA = datetime.timedelta(hours=23)


start = datetime.datetime.now() - datetime.timedelta(hours=23) + datetime.timedelta(seconds=CLOCK_SKEW_COMPENSATION)
if options.start:
    start = datetime.datetime.strptime(options.start, "%Y-%m-%d %H:%M:%S")

end = start + datetime.timedelta(hours=23)
if options.end:
    end = datetime.datetime.strptime(options.end, "%Y-%m-%d %H:%M:%S")

syslog.openlog(os.path.basename(__file__), syslog.LOG_PID, syslog.LOG_USER)


from ietf.sync.iana import *

syslog.syslog("Updating history log with new changes from IANA from %s, period %s - %s" % (settings.IANA_SYNC_CHANGES_URL, start, end))

t = start
while t < end:
    # the IANA server doesn't allow us to fetch more than a certain
    # period, so loop over the requested period and make multiple
    # requests if necessary

    text = fetch_changes_json(settings.IANA_SYNC_CHANGES_URL, t, min(end, t + MAX_INTERVAL_ACCEPTED_BY_IANA))
    syslog.syslog("Retrieved the JSON: %s" % text)

    changes = parse_changes_json(text)
    added_events, warnings = update_history_with_changes(changes, send_email=options.send_email)

    for e in added_events:
        syslog.syslog("Added event for %s %s: %s (parsed json: %s)" % (e.doc_id, e.time, e.desc, e.json))

    for w in warnings:
        syslog.syslog("WARNING: %s" % w)

    t += MAX_INTERVAL_ACCEPTED_BY_IANA