# tweet_correlation.py - Calculate the correlation of two users' tweet clouds,
# based on data from http://tweetstats.com. You need to have visited this site
# before using the app, as this app relies on the cached data made when you
# first use the service.
#
# This module also exports functionality for retrieving and manipulating a
# cached tweet cloud.
##############################################################################
# Copyright (c) 2008 Zachary Voase
# 
# 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 math
import operator
import urllib2
 
try:
    import json
except ImportError:
    try:
        import simplejson as json
    except ImportError:
        from django.utils import simplejson as json
 
 
class TweetCloud(dict):
    
    """
    >>> tweet_cloud = TweetCloud('zvoase')
    >>> print repr(tweet_cloud)
    TweetCloud('zvoase')
    >>> print tweet_cloud
    http://tweetstats.com/cache/zvoase/tag_cloud.json
    >>> print tweet_cloud['django'] #doctest: +SKIP
    65
    >>> tweet_cloud_2 = TweetCloud('stephenfry')
    >>> print tweet_cloud.compare(tweet_cloud)
    1.0
    >>> print tweet_cloud.compare(tweet_cloud_2) #doctest: +SKIP
    0.71247443083593875
    >>> comparison_1 = tweet_cloud.compare(tweet_cloud_2)
    >>> comparison_2 = tweet_cloud_2.compare(tweet_cloud)
    >>> comparison_1 == comparison_2
    True
    """
    
    def __init__(self, username, safe=False):
        self.username = username
        if not safe:
            self._load_data()
    
    def __repr__(self):
        return 'TweetCloud(%r)' % (self.username,)
    
    def __str__(self):
        return 'http://tweetstats.com/cache/%s/tag_cloud.json' % (
            self.username,)
    
    def _load_data(self):
        """Load tweet cloud data from http://tweetstats.com."""
        try:
            conn = urllib2.urlopen(
                'http://tweetstats.com/cache/%s/tag_cloud.json' % (
                self.username,))
        except urllib2.HTTPError, exc:
            if exc.code == 404:
                raise Exception('Please visit tweetstats '
                    '(http://tweetstats.com) before using this application.')
        try:
            data = json.load(conn)
        finally:
            conn.close()
        for word, count in data:
            self[word] = count
    
    def filter_replies(self):
        """Return a new TweetCloud with stats only on this one's replies."""
        replies = self.__class__(self.username, safe=True)
        for word in self:
            if word.startswith('@'):
                replies[word] = self[word]
        return replies
    
    def filter_words(self):
        """Return a new TweetCloud with stats only on this one's words."""
        words = self.__class__(self.username, safe=True)
        for word in self:
            if not word.startswith('@'):
                words[word] = self[word]
        return words
    
    def compare(self, tag_cloud):
        """Return a comparison coefficient between two TweetClouds."""
        keys = set(self.keys()).intersection(set(tag_cloud.keys()))
        result = {}
        for key in keys:
            result[key] = min((self[key], tag_cloud[key]))
        return 2 * (float(sum(result.values())) /
            (sum(self.values()) + sum(tag_cloud.values())))
 
BOTH = 0
WORDS_ONLY = 1
REPLIES_ONLY = 2
 
def compare(username1, username2, consider=BOTH):
    tc1 = TweetCloud(username1)
    tc2 = TweetCloud(username2)
    if consider == WORDS_ONLY:
        tc1 = tc1.filter_words()
        tc2 = tc2.filter_words()
    elif consider == REPLIES_ONLY:
        tc1 = tc1.filter_replies()
        tc2 = tc2.filter_replies()
    return tc1.compare(tc2)
 
if __name__ == '__main__':
    import doctest
    doctest.testmod(verbose=True)