READ_OLD_TWEETS = true;

RECORD_NEW_TWEETS = true;

tweet_file = flagOption('-f', 'tweets.txt');

app_port = flagOption('-p', 8000);

tracking_keyword = flagOption('-t', null);

user_pass = flagOption('-u', null);

if (!user_pass) {

    console.log("You must provide user credentials on the command-line, e.g. node tweetcast.js -u user:pass")

    process.exit();

}

if (!tracking_keyword) {

    console.log("You must provide keyword(s) on the command-line, e.g. node tweetcast.js -t Bieber")

    process.exit();

}

console.log("Tracking keyword "+tracking_keyword);

var fs = require('fs'),

    http = require('http'),

    https = require('https'),

    socketio = require('socket.io'),

    app = http.createServer(httpHandler),

    io = socketio.listen(app)

    tweets = [],

    tweet_ids = [],

    keys_to_delete = [

        'in_reply_to_screen_name',

        'in_reply_to_user_id',

        'retweeted',

        'place',

        'geo',

        'source',

        'contributors',

        'coordinates',

        'retweet_count',

        'favorited',

        'truncated',

        'possibly_sensitive'

    ],

    user_keys_to_delete = [

        'default_profile_image',

        'show_all_inline_media',

        'contributors_enabled',

        'profile_sidebar_fill_color',

        'created_at',

        'lang',

        'time_zone',

        'profile_sidebar_border_color',

        'follow_request_sent',

        'profile_background_image_url',

        'profile_background_image_url_https',

        'followers_count',

        'description',

        'url',

        'geo_enabled',

        'profile_use_background_image',

        'default_profile',

        'following',

        'profile_text_color',

        'is_translator',

        'favourites_count',

        'listed_count',

        'friends_count',

        'profile_link_color',

        'protected',

        'location',

        'notifications',

        'profile_image_url_https',

        'statuses_count',

        'verified',

        'profile_background_color',

        'profile_background_tile',

        'utc_offset'

    ],

    content_types = {

        css : "text/css; charset=utf-8",

        html : "text/html; charset=utf-8",

        js : "text/javascript; charset=utf-8",

        png : "image/png"

    };

function wrapContentType(ext) {

    return {

        "Content-Type" : ( content_types[ext] ? content_types[ext] : 'text/plain' )

    }

}

function httpHandler(req, res) {

    console.log("HTTP Request for URL "+req.url);

    var url = req.url.split('?')[0];

    url = __dirname + "/client" + url + ( url[url.length - 1] == "/" ? "index.html" : "" );

    var ext = url.split('.').slice(-1)[0].toLowerCase();

    fs.readFile( url, function(err, data) {

        if (err) {

            console.log("Error 404");

            res.writeHead(404);

            return res.end('File not found');

        }

        res.writeHead(200, wrapContentType(ext));

        res.end(data);

    });

}

function flagOption(flag, defaultValue) {

    var flagPos = process.argv.indexOf(flag);

    return ( flagPos != -1 && flagPos < process.argv.length - 1) ? process.argv[flagPos + 1] : defaultValue;

}

function addToList(tweet) {

    if (tweet_ids.indexOf(tweet.id) != -1) {

        console.log("Error: Tweet already in list");

        return false;

    }

    tweets.push(tweet);

    tweet_ids.push(tweet.id);

    return true;

}

function textids(object) {

    for (var key in object) {

        // Workaround for Unicode bug in socket.io.

        if (typeof object[key] == "string") {

            var tmp = '';

            for (var i = 0; i < object[key].length; i++) {

                tmp += ( object[key].charCodeAt(i) < 128 ? object[key].charAt(i) : "&#" + object[key].charCodeAt(i) + ";" );

            }

            object[key] = tmp;

        }

        if (key.substr(-2) == 'id') {

            object[key] = object[key + '_str'];

            delete object[key + '_str'];

        }

    }

}

function readTweetsFromFile(file_name) {

    console.log("Trying to read tweets from " + file_name);

    try {

        var oldtweets = fs.readFileSync(file_name, 'utf8').split('\n');

        var tweetscopied = 0;

        for (var i in oldtweets) {

            if (oldtweets[i].length > 0) {

                addToList(JSON.parse(oldtweets[i]));

                tweetscopied++;

            }

        }

        console.log(tweetscopied + " tweets copied");

    }

    catch (err) {

        console.log("Error opening "+file_name);

    }

}

function requestTweets() {

    console.log("Fetching tweets from https://stream.twitter.com/1/statuses/filter.json")

    var writestream = null;

    var req = https.request({

        host: "stream.twitter.com",

        path: "/1/statuses/filter.json",

        method: "POST",

        headers: {

            'Authorization': 'Basic ' + new Buffer( user_pass ).toString('base64'),

            'Content-Type': 'application/x-www-form-urlencoded'

        }

    }, function(res) {

        writestream = fs.createWriteStream( tweet_file, { flags: 'a+', encoding: 'utf-8' } );

        console.log('Response received, status : ' + res.statusCode);

        res.setEncoding('utf8');

        res.on('data', function(chunk) {

            var newdata = chunk.split('\r\n'),

                tweetpos = tweets.length;

            try {

                for (var i in newdata) {

                    if (newdata[i].length > 0) {

                        var tweet = JSON.parse(newdata[i]);

                        textids(tweet);

                        for (var j in keys_to_delete) {

                            delete tweet[keys_to_delete[j]];

                        }

                        textids(tweet.user);

                        for (var j in user_keys_to_delete) {

                            delete tweet.user[user_keys_to_delete[j]];

                        }

                        if (tweet.retweeted_status) {

                            textids(tweet.retweeted_status);

                            for (var j in keys_to_delete) {

                                delete tweet.retweeted_status[keys_to_delete[j]];

                            }

                        }

                    /*    tweet.date_value = Date.parse(tweet.created_at); */

                        if (addToList(tweet)) {

                            writestream.write(JSON.stringify(tweet)+'\n');

                        }

                    }

                }

                io.sockets.emit('update', {

                        "new_tweets" : tweets.slice(tweetpos)

                    });

                console.log("New tweets received. We now have", tweets.length, "tweets in memory");

            }

            catch(err) {

                console.log(err.message);

            }

        });

    });

    req.write('track=' + encodeURIComponent( ( tracking_keyword ) ) );

    req.end();

}

app.listen(app_port);

console.log("Listening on port: "+app_port);

if (READ_OLD_TWEETS) {

    readTweetsFromFile(tweet_file);

} else {

    console.log("Reading old tweets disabled !");

}

if (RECORD_NEW_TWEETS) {

    requestTweets();

} else {

    console.log("Recording new tweets disabled !");

}

io.set('log level', 0);

io.sockets.on('connection', function(socket) {

    console.log("New connection from "+socket.handshake.address.address);

    socket.emit('initial_data', {

        "tweets" : tweets

    });

});