Class to detect @username style replies in comments.

var regexpQuote = require("regexp-quote");

/**

 * @singleton

 * Detection of `@username` style replies inside comments.

 */

var ReplyDetector = {

    /**

     * Determines if the comment is intended as a reply to some of the

     * other users who have posted in this thread.

     *

     * @param {String} comment Plain comment text that was posted.

     * @param {Object[]} users Array of users who have posted to this

     * thread.  This should be a unique list without duplicates and

     * without the user who's the author of posted comment.

     * @return {Object[]} Array of users that were mentioned in the

     * comment, if any.

     */

    detect: function(comment, users) {

        // sort users with longer names to be at the beginning.

        // This way when comment mentions @john.doe

        // and we have users "john" and "john.doe",

        // then user "john.doe" will be matched first.

        users.sort(function(a, b) {

            return b.username.length - a.username.length;

        });

        // split comment into parts where each part begins with @-sign

        var parts = comment.split(/@/);

        // ignore the part before the first @-sign

        parts.shift();

        // check each remaining part against all the usernames

        var detectedUsers = [];

        parts.forEach(function(snippet) {

            var user = this.matchUser(snippet, users);

            if (user && detectedUsers.indexOf(user) === -1) {

                detectedUsers.push(user);

            }

        }.bind(this));

        return detectedUsers;

    },

    // Returns the first user in list who's name matches with the

    // beginning of the given text snippet.

    matchUser: function(snippet, users) {

        for (var i=0; i<users.length; i++) {

            var user = users[i];

            var re = new RegExp('^'+regexpQuote(user.username) + '\\b', "i");

            if (re.test(snippet)) {

                return user;

            }

        }

        return false;

    }

};

module.exports = ReplyDetector;

        "connect-mysql-session": "~0.1",

        "marked": "~0.2",

        "sanitizer": "~0.0",

        "nodemailer": "~0.3"

        "nodemailer": "~0.3",

        "regexp-quote": "0.0.0"

    }

}

describe("ReplyDetector#detect", function() {

    var ReplyDetector = require("../lib/reply_detector");

    // helpers

    function objWrap(username) {

        return {username: username};

    }

    function objUnwrap(user) {

        return user.username;

    }

    function detect(comment, users) {

        return ReplyDetector.detect(comment, users.map(objWrap)).map(objUnwrap);

    }

    // no replies

    it("finds no replies if no users given", function() {

        expect(detect("@rene: Blah", [])).toEqual([]);

    });

    it("finds no replies if text contains no '@' char at all", function() {

        expect(detect("Some text... blah blah...", ["mary", "john"])).toEqual([]);

    });

    it("finds no replies if @mentions don't match up with users", function() {

        expect(detect("@fred: blah blah...", ["mary", "john"])).toEqual([]);

    });

    it("finds no replies if @mentions don't exactly match up with users", function() {

        expect(detect("@johnny: blah blah...", ["mary", "john"])).toEqual([]);

    });

    // single reply

    it("finds a reply to john when text begins with @john", function() {

        expect(detect("@john Thanks.", ["mary", "john", "nige"])).toEqual(["john"]);

    });

    it("finds a reply to john when text begins with @john:", function() {

        expect(detect("@john: Thanks.", ["mary", "john", "nige"])).toEqual(["john"]);

    });

    it("finds a reply to john when text begins with **@john:**", function() {

        expect(detect("**@john:** Thanks.", ["mary", "john", "nige"])).toEqual(["john"]);

    });

    it("finds a reply to john when text begins with @John", function() {

        expect(detect("@John Thanks.", ["mary", "john", "nige"])).toEqual(["john"]);

    });

    it("finds a reply to john when text contains @john", function() {

        expect(detect("Hello @john, Thanks.", ["mary", "john", "nige"])).toEqual(["john"]);

    });

    it("finds a reply to john when text ends with @john", function() {

        expect(detect("Thanks @john", ["mary", "john", "nige"])).toEqual(["john"]);

    });

    it("finds a reply to 15john8 when text contains @15john8", function() {

        expect(detect("Hello @15john8, Thanks.", ["john", "15john8", "15"])).toEqual(["15john8"]);

    });

    it("finds a reply to foo*bar when text contains @foo*bar", function() {

        expect(detect("Hello @foo*bar, Thanks.", ["nick", "foo*bar", "john"])).toEqual(["foo*bar"]);

    });

    it("finds a reply to susan.dada when text contains @susan.dada", function() {

        expect(detect("Hello @susan.dada, Thanks.", ["susan", "susan.dada", "dada"])).toEqual(["susan.dada"]);

    });

    it("finds a reply to John Lennon when text contains @John Lennon:", function() {

        expect(detect("To @John Lennon: Don't know", ["Susan", "John Lennon"])).toEqual(["John Lennon"]);

    });

    it("Finds a reply to John when text contains @John and we have users 'John' and 'John Lennon' ", function() {

        expect(detect("@John: WTF!", ["John Lennon", "John"])).toEqual(["John"]);

    });

    // multiple replies

    it("finds a reply to both john & mary when lines in text begin with @john and @mary", function() {

        expect(detect("@john Agree.\n@mary Thanks.", ["john", "nige", "mary"])).toEqual(["john", "mary"]);

    });

    it("finds a reply to both john & mary when text contains @john and @mary", function() {

        expect(detect("**@john, @mary:** I agree!", ["john", "nige", "mary"])).toEqual(["john", "mary"]);

    });

    // duplicate replies

    it("finds a single reply to john when @john mentioned multiple times", function() {

        expect(detect("@john:Thanks.\n@john: and be good.", ["ronald", "john", "mary"])).toEqual(["john"]);

    });

});