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

# Copyright (c) 2014 Vincent Celis
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import pymongo
import sys

from pymongo import MongoClient

# Establish database connection
client = MongoClient('mongodb://localhost', safe=True)

def find():
  """Remove the lowest grade of type 'homework' for each student"""

  # Getting the database
  db = client.school
  # Getting the collection
  students = db.students

  try:
    # Find all that matches our query and selector
    cursor = students.find({})
  except:
    print 'Unexpected error:', sys.exc_info()[1]

  for student in cursor:
    homeworks = sorted([x for x in student['scores'] if x['type'] == 'homework'], key=lambda k: k['score'])
    others = [x for x in student['scores'] if x['type'] != 'homework']
    
    student['scores'] = homeworks[1:] + others
    students.save(student)

find()

"""To verify that you have completed this task correctly, provide the identity of the student with the highest average in the class with following query that uses the aggregation framework. The answer will appear in the _id field of the resulting document.

  db.students.aggregate( { '$unwind' : '$scores' } , { '$group' : { '_id' : '$_id' , 'average' : { $avg : '$scores.score' } } } , { '$sort' : { 'average' : -1 } } , { '$limit' : 1 } )
"""