from __future__ import print_function
import httplib2
import os

from apiclient import discovery
import oauth2client
from oauth2client import client
from oauth2client import tools
from event import Event

from datetime import datetime
import pytz
utc=pytz.UTC

try:
    import argparse
    flags = argparse.ArgumentParser(parents=[tools.argparser]).parse_args()
except ImportError:
    flags = None

# If modifying these scopes, delete your previously saved credentials
# at ~/.credentials/projet-wdm-gcal.json
SCOPES = 'https://www.googleapis.com/auth/calendar.readonly'
CLIENT_SECRET_FILE = 'client_secret.json'
APPLICATION_NAME = 'Google Calendar API Python'


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, 'projet-wdm-gcal.json')

    store = oauth2client.file.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
        if flags:
            credentials = tools.run_flow(flow, store, flags)
        else: # Needed only for compatibility with Python 2.6
            credentials = tools.run(flow, store)
        print('Storing credentials to ' + credential_path)
    return credentials



def find_list_event_gcal(events):
    list_event = []

    if not events:
        print('No upcoming events found.')
        return list_event

    for event in events:
        if 'dateTime' in event['start']:
            # replace last ':' by ''
            start = event['start']['dateTime']
            start = start.rsplit(':', 1)
            start = "".join(start)
            date = datetime.strptime(start, '%Y-%m-%dT%H:%M:%S%z')
        else:
            # TODO strptime, quel est le format dans ce cas ?
            date = event['start']['date']

        date = date.replace(tzinfo = None)
        location = event.get('location', b'')
        if (not isinstance(location,str)):
            location = location.decode()

        description = event.get('description', 'no description')
        if (not isinstance(description,str)):
            description = description.decode()
        list_event.append(Event('gcal_' + event['id'], date, location, description))
    return list_event

def get_list_event_gcal():
    """Shows basic usage of the Google Calendar API.

    Creates a Google Calendar API service object and outputs a list of the next
    10 events on the user's calendar.
    """
    credentials = get_credentials()
    http = credentials.authorize(httplib2.Http())
    service = discovery.build('calendar', 'v3', http=http)

    now = datetime.utcnow().isoformat() + 'Z' # 'Z' indicates UTC time
    print('Getting the upcoming 10 events from Google Calendar...')
    eventsResult = service.events().list(
        calendarId='primary', timeMin=now, maxResults=10, singleEvents=True,
        orderBy='startTime').execute()
    events = eventsResult.get('items', [])

    return find_list_event_gcal(events)