#!/usr/bin/env python

import sys
import json
import operator
import math

true_path = 'true_recoms.txt'
team_path = 'recoms.txt'

result = { 'score': 0, 'details': 'failed' }

true_recs = {}

with open(true_path) as f:
    for line in f:
        data = json.loads(line)
        true_recs[data['item']] = data['true_recoms']

ndcg_sum = 0
lines_number = 0

with open(team_path) as f:
    for line in f:
        data = json.loads(line)
        lines_number += 1

        trs = true_recs[data['item']]
        tmrs = data['recoms']

        sorted_trs = sorted(trs.items(), key = operator.itemgetter(1), reverse = True)
        sorted_tmrs = sorted(tmrs.items(), key = operator.itemgetter(1), reverse = True)

        dcg = 0
        idcg = 0

        for i in range(len(trs)):
            delta = sorted_trs[i][1]
            if i + 1 != 1:
                delta = delta / float(math.log(i + 1, 2))
            idcg += delta

        for i in range(len(tmrs)):
            if sorted_tmrs[i][0] in trs:
                delta = trs[sorted_tmrs[i][0]]
                if i + 1 != 1:
                    delta = delta / float(math.log(i + 1, 2))
                dcg += delta

        ndcg_sum += dcg / idcg

    if lines_number != len(true_recs.keys()):
        result['details'] = 'Wrong lines number'
    else:
        result['details'] = 'ok'
        result['score'] = ndcg_sum / lines_number


print repr(result)