import caldav
import vobject
import copy # ugh
from cStringIO import StringIO
from datetime import datetime, timedelta, date
from dateutil import zoneinfo
from flask import Flask, g, json, make_response

app = Flask('hs_cal')
app.config.from_pyfile('config.cfg')

server = app.config['SERVER']
location = app.config['CALENDAR']
tz = zoneinfo.gettz(app.config['TIMEZONE'])

@app.before_request
def connect():
    client = caldav.DAVClient(server)
    g.calendar = caldav.Calendar(client, server + location)

def shift_date(event, rec_dtstart):
    orig_st = event.dtstart.value
    orig_et = event.dtend.value
    duration = orig_et - orig_st
    event.dtstart.value = rec_dtstart
    event.dtend.value = rec_dtstart + duration

# shim-o-rama
def expand_recurrences(event, start, end):
    rrs = event.getrruleset()
    print event.__dict__
    if rrs:
        return [fix_date(copy.deepcopy(event), dts) 
                for dts in rrs.between(start, end, inc=True)]
    else:
        return [event]

def objectify_event(event):
    def nullable(event, attr):
        a = getattr(event, attr, None)
        return a and a.value
    return dict((attr, nullable(event, attr)) for attr in 
            ['summary', 'description', 'dtstart', 'dtend', 'categories'])

def jsonify_events(events):
    def encode(o):
        if isinstance(o, datetime) :
            return o.strftime('%d/%m/%Y %H:%M')
        if isinstance(o, date):
            return o.strftime('%d/%m/%Y')
        raise TypeError(type(o))
    return make_response(json.dumps(dict(events=events),
        default=encode, indent=app.config.get('INDENT')))

@app.route('/')
def get_events_range(start=None, end=None):
    start = start or datetime.today()
    if not end or (end - start).days > 31:
        end = start + timedelta(days=31)
    start = start.replace(tzinfo=tz)
    end = end.replace(tzinfo=tz)
    res = []
    for event in g.calendar.date_search(start, end):
        vev = event.instance.vevent
        res.extend(expand_recurrences(vev, start, end))
    return jsonify_events(map(objectify_event, res))
    

@app.route('/from/<start>/to/<end>/')
def range_query(start, end):
    fstring = '%d-%m-%Y'
    return get_events_range(datetime.strptime(start, fstring),
            datetime.strptime(end, fstring))

if __name__ == '__main__':
    app.debug = True
    app.run()