#!/usr/bin/env python
import os
import sys
import time
import errno
import datetime
import optparse
import urlparse
import itertools
import traceback
from os import path

sys.path.append(path.join(path.dirname(__file__), '..'))
import humbug

parser = optparse.OptionParser(r"""

%prog \
    --user foo@humbughq.com \
    --api-key 0123456789abcdef0123456789abcdef \
    --calendar http://www.google.com/calendar/feeds/foo%40humbughq.com/private-fedcba9876543210fedcba9876543210/basic

    Send yourself reminders on Humbug of Google Calendar events.

    To get the calendar URL:
      - Load Google Calendar in a web browser
      - Find your calendar in the "My calendars" list on the left
      - Click the down-wedge icon that appears on mouseover, and select "Calendar settings"
      - Copy the link address for the "XML" button under "Private Address"

    Run this on your personal machine.  Your API key and calendar URL are revealed to local
    users through the command line.

    Depends on: python-gdata
""")

parser.add_option('--user',
    dest='user',
    action='store',
    help='Humbug user email address',
    metavar='EMAIL')
parser.add_option('--api-key',
    dest='api_key',
    action='store',
    help='API key for that user [default: read ~/.humbug-api-key]')
parser.add_option('--calendar',
    dest='calendar',
    action='store',
    help='Google Calendar XML "Private Address"',
    metavar='URL')
parser.add_option('--site',
    dest='site',
    default="https://humbughq.com",
    action='store',
    help='Humbug site [default: https://humbughq.com]',
    metavar='URL')
parser.add_option('--interval',
    dest='interval',
    default=10,
    type=int,
    action='store',
    help='Minutes before event for reminder [default: 10]',
    metavar='MINUTES')

(options, args) = parser.parse_args()

if not options.api_key:
    try:
        with open(path.join(os.environ['HOME'], '.humbug-api-key'), 'r') as f:
            options.api_key = f.read().strip()
    except IOError as e:
        if e.errno != errno.ENOENT:
            raise

if not (options.user and options.api_key and options.calendar):
    parser.error('You must specify --user, --api-key, and --calendar')

try:
    from gdata.calendar.client import CalendarClient
except ImportError:
    parser.error('Install python-gdata')

def get_calendar_url():
    parts = urlparse.urlparse(options.calendar)
    pat = path.split(parts.path)
    if pat[1] != 'basic':
        parser.error('The --calendar URL should be the XML "Private Address" ' +
                     'from your calendar settings')
    return urlparse.urlunparse((parts.scheme, parts.netloc, pat[0] + '/full',
                                '', 'futureevents=true&orderby=startdate', ''))

calendar_url = get_calendar_url()

humbug = humbug.HumbugAPI(
    email=options.user,
    api_key=options.api_key,
    site=options.site,
    verbose=True)

def get_events():
    feed = CalendarClient().GetCalendarEventFeed(uri=calendar_url)

    for event in feed.entry:
        start = event.when[0].start.split('.')[0]
        start = datetime.datetime.strptime(start, '%Y-%m-%dT%H:%M:%S')
        yield (event.uid.value, start, event.title.text)

# Our cached view of the calendar, updated periodically.
events = []

# Unique keys for events we've already sent, so we don't remind twice.
sent = set()

def send_reminders():
    global sent

    messages = []
    keys = set()
    now = datetime.datetime.now()

    for uid, start, title in events:
        dt = start - now
        if dt.days == 0 and dt.seconds < 60*options.interval:
            # The unique key includes the start time, because of
            # repeating events.
            key = (uid, start)
            if key not in sent:
                line = '%s starts at %s' % (title, start.strftime('%H:%M'))
                print 'Sending reminder:', line
                messages.append(line)
                keys.add(key)

    if not messages:
        return

    if len(messages) == 1:
        message = 'Reminder: ' + messages[0]
    else:
        message = 'Reminder:\n\n' + '\n'.join('* ' + m for m in messages)

    humbug.send_message(dict(
        type      = 'private',
        to = options.user,
        content   = message))

    sent |= keys

# Loop forever
for i in itertools.count():
    try:
        # We check reminders every minute, but only
        # download the calendar every 10 minutes.
        if not i % 10:
            events = list(get_events())
        send_reminders()
    except:
        traceback.print_exc()
    time.sleep(60)