import datetime
import httplib2
import urllib
import os

from apiclient import discovery
from oauth2client import client
from oauth2client import tools
from oauth2client.file import Storage

import icalendar


TIMEDELTA_SYNCHRO = datetime.timedelta(days=4) # Number of days to look for
# for synchronization
with open('ntnoe_credentials') as f:
    NTNOE_ID,NTNOE_PASS,_ = f.read().split('\n')


SCOPES = 'https://www.googleapis.com/auth/calendar'
CLIENT_SECRET_FILE = 'client_secret.json'
APPLICATION_NAME = 'Google Calendar API Python Quickstart'


class Event:
    # ColorId corresponding to course code
    EVENT_COLOR = {
        '9' : '9', # Amphi
        '11' : '10', # TL
        '10' : '6', # TD
        '13' : '5', # Autre
        '12' : '3', # Exam

    }

    def __init__(self, e):
        """ Initialize an event from a `icalendar.cal.Event`."""
        self.summary = e.decoded('SUMMARY').decode('utf-8')
        self.start = e.decoded('DTSTART')
        self.end = e.decoded('DTEND')
        self.location = e.decoded('LOCATION').decode('utf-8')
        self.colorid = self.EVENT_COLOR.get(e.decoded('DESCRIPTION').decode('utf-8'), '1')

    def __str__(self):
        return str(self.as_google())

    def as_google(self):
        return {
            'summary' : self.summary,
            'location' : self.location,
            'start' : {
                'dateTime' : self.start.isoformat(),
                'timeZone' : 'Europe/Paris',
            },
            'end' : {
                'dateTime' : self.end.isoformat(),
                'timeZone' : 'Europe/Paris',
            },
            'colorId' : self.colorid,
            'reminders': {
                'useDefault': False,
                'overrides': [],
            },

        }


def get_credentials():
    """Gets valid user credentials from storage.

    If nothing has been stored, or if the stored credentials are invalid,
    the OAuth2 flow is completed to obtain the new credentials.

    Returns:
        Credentials, the obtained credential.
    """
    home_dir = os.path.expanduser('~')
    credential_dir = os.path.join(home_dir, '.credentials')
    if not os.path.exists(credential_dir):
        os.makedirs(credential_dir)
    credential_path = os.path.join(credential_dir, 'ntnoe.json')

    store = Storage(credential_path)
    credentials = store.get()
    if not credentials or credentials.invalid:
        flow = client.flow_from_clientsecrets(CLIENT_SECRET_FILE, SCOPES)
        flow.user_agent = APPLICATION_NAME
        print('Storing credentials to ' + credential_path)
        credentials = tools.run_flow(flow, store)

    return credentials


def get_ntnoe():
    url = "http://ntnoe.metz.supelec.fr/ical/EdTcustom/Eleves/edt_{}.ics"
    url = url.format(NTNOE_ID)

    h = httplib2.Http()
    h.add_credentials(NTNOE_ID,NTNOE_PASS)
    data = {'envoyer':'Utf8_All','submit':'G%E9n%E9rer'}

    h.request(
        "https://ntnoe.metz.supelec.fr/ical/index.php",
        body=urllib.parse.urlencode(data),
        method='POST',
    )
    # resp,content = h.request(
        # "https://ntnoe.metz.supelec.fr/ical/EdTcustom/Eleves/edt_{id}.ics".format(id=NTNOE_ID),
    # )
    # print(resp,content)
    # TODO : download from ntnoe



def main():
    """Get the events on NTNOE the puts them on Google Calendar.

    """
    get_ntnoe()
    credentials = get_credentials()
    http = credentials.authorize(httplib2.Http())
    service = discovery.build('calendar', 'v3', http=http)

    with open("edt_" + NTNOE_ID + ".ics") as f:
        c = icalendar.Calendar.from_ical(f.read())

    now = datetime.datetime.now()
    then = now + TIMEDELTA_SYNCHRO
    response = service.events().list(
        calendarId='primary',
        timeMin=now.isoformat()+'Z',
        timeMax=then.isoformat()+'Z',
    ).execute()

    existing_events = set()
    for e in response['items']:
        if 'summary' in e.keys():
            existing_events.add(e['summary'])
    for e in c.walk('VEVENT'):
        event = Event(e)
        t = (
            event.summary,
            event.start.isoformat(),
            event.end.isoformat(),
            event.location
        )
        if now >= event.end or event.start >= then:
            continue

        if existing_events.intersection({event.summary}):
            continue
        else:
            print(event.summary)

        event = service.events().insert(
            calendarId='primary',
            body=event.as_google()
        ).execute()
        print("Added event : {}".format(event.get('htmlLink')))

if __name__ == '__main__':
    main()