Lunch-O/luncho/blueprints/voting.py

#!/usr/bin/env python
# -*- encoding: utf-8 -*-

"""Voting"""

import datetime
import logging

from flask import Blueprint
from flask import jsonify
from flask import request
from flask import current_app

from luncho.helpers import ForceJSON
from luncho.helpers import auth

from luncho.server import db
from luncho.server import Group
from luncho.server import Vote
from luncho.server import CastedVote
from luncho.server import Place

from luncho.exceptions import LunchoException
from luncho.exceptions import UserIsNotMemberException
from luncho.exceptions import ElementNotFoundException

LOG = logging.getLogger('luncho.blueprints.voting')

voting = Blueprint('voting', __name__)


# ----------------------------------------------------------------------
#  Exceptions
# ----------------------------------------------------------------------

class VoteAlreadyCastException(LunchoException):
    """The user already voted today.

    .. sourcecode:: http
       HTTP/1.1 406 Not Acceptable
       Content-Type: text/json

       { "status": "ERROR", "message": "User already voted today" }
    """
    def __init__(self):
        super(VoteAlreadyCastException, self).__init__()
        self.status = 406
        self.message = 'User already voted today'


class InvalidNumberOfPlacesCastedException(LunchoException):
    """The number of places in the vote casted is invalid.

    .. sourcecode:: http
       HTTP/1.1 406 Not Acceptable
       Content-Type: text/json

       { "status": "ERROR",
         "message": "The vote must register {places} places" }
    """
    def __init__(self, places):
        super(InvalidNumberOfPlacesCastedException, self).__init__()
        self.status = 406
        self.message = 'The must register {places} places'.format(places)


class PlaceDoesntBelongToGroupException(LunchoException):
    """The indicated places do not belong to the group.

    .. sourcecode:: http
       http/1.1 404 Not Found
       Content-Type: text/json

       { "status": "ERROR",
         "message": "Places are not part of this group",
         "places": [<place>, <place>, ...]}
    """
    def __init__(self, places):
        super(PlaceDoesntBelongToGroupException, self).__init__()
        self.status = 404
        self.message = 'Places are not part of this group'
        self.places = places

    def _json(self):
        super(PlaceDoesntBelongToGroupException, self)._json()
        self.json['places'] = self.places


# ----------------------------------------------------------------------
#  Voting
# ----------------------------------------------------------------------

@voting.route('<int:group_id>/', methods=['POST'])
@ForceJSON(required=['choices'])
@auth
def cast_vote(group_id):
    """Cast a vote for a group. A user can cast a vote in a single group
    per day.
    """
    # check if the group exists
    group = Group.query.get(group_id)
    if not group:
        raise ElementNotFoundException('Group')

    # check if the user belongs to the group
    if request.user not in group.users:
        LOG.debug('User is not member')
        raise UserIsNotMemberException()

    # check if the user voted today already, for any group
    today = datetime.date.today()
    today_vote = Vote.query.filter_by(user=request.user.username,
                                      created_at=today).first()
    if today_vote:
        LOG.debug('User already voted today')
        raise VoteAlreadyCastException()

    # check the number of votes the user casted
    choices = request.as_json.get('choices')
    max_places = min(current_app.config['PLACES_IN_VOTE'],
                     len(group.places))
    if len(choices) != max_places:
        LOG.debug('Max places = {max_places}, voted for {choices}',
                  max_places=max_places, choices=len(choices))
        raise InvalidNumberOfPlacesCastedException()

    # check if the places exist and are part of the group
    # (don't vote yet, so we can stop the whole thing if there is anything
    #  wrong)
    for place_id in request.as_json.get('choices'):
        place = Place.query.get(place_id)
        if not place:
            raise ElementNotFoundException('Place')

        if not place in group.places:
            raise PlaceDoesntBelongToGroupException(place_id)

    # finally, cast the vote
    vote = Vote(request.user, group_id)
    db.session.add(vote)
    db.session.commit()     # so vote gets an id
    for (pos, place_id) in enumerate(request.as_json.get('choices')):
        place = CastedVote(vote, pos, place_id)
        db.session.add(place)

    db.session.commit()

    return jsonify(status='OK')