(function ($) {
	function widget(element, options, callback) {
		this.element = element;
		this.options = options;
		this.callback = $.isFunction(callback) ? callback : $.noop;
	}
 
    function getCommits(user, repo, branch, callback) {
        $.ajax({
        url: "https://api.github.com/repos/" + user + "/" + repo + "/commits?sha=" + branch,
        dataType: 'jsonp',
        success: callback
        });
    }

	widget.prototype = (function() {

		function _widgetRun(widget) {
			if (!widget.options) {
				widget.element.append('<span class="error">Options for widget are not set.</span>');
				return;
			}
			var callback = widget.callback;
			var element = widget.element;
			var user = widget.options.user;
			var repo = widget.options.repo;
			var branch = widget.options.branch;
			var avatarSize = widget.options.avatarSize || 20;
			var last = widget.options.last == undefined ? 0 : widget.options.last;
			var limitMessage = widget.options.limitMessageTo == undefined ? 0 : widget.options.limitMessageTo;

			element.append('<p>Widget intitalization, please wait...</p>');
			getCommits(user, repo, branch, function (data) {
				var commits = data.data;
				var totalCommits = (last < commits.length ? last : commits.length);

				element.empty();
				var list = $('<ul>').appendTo(element);

				for (var c = 0; c < totalCommits; c++) {
                       commit = commits[c];
					list.append(
						'<li>' +
						' ' + ((commit.author != null) ? avatar(commit.author.gravatar_id, avatarSize) : "")+
                        ' ' + ((commit.author != null) ? author(commit.author.login) : commit.commit.committer.name) +
						' committed ' + message(commit.commit.message, commit.sha) +
						' ' + when(commit.commit.committer.date) +
						'</li>');
				}
				element.append('<p class="github-commits-widget-by">by <a href="https://github.com/alexanderbeletsky/github.commits.widget">github.commits.widget</a></p>');
				callback(element);

				function avatar(hash, size) {
					return '<img class="github-avatar" src="http://www.gravatar.com/avatar/' + hash + '?s=' + size + '"/>';
				}

				function author(login) {
                    return '<a class="github-user" href="https://github.com/' + login + '">' + login + '</a>';
				}

				function message(commitMessage, sha) {
					if (limitMessage > 0 && commitMessage.length > limitMessage)
					{
						commitMessage = commitMessage.substr(0, limitMessage) + '...';
					}
					return '"' + '<a class="github-commit" href="https://github.com/' + user + '/' + repo + '/commit/' + sha + '">' + commitMessage + '</a>"';
				}

				function when(commitDate) {
					var commitTime = new Date(commitDate).getTime();
					var todayTime = new Date().getTime();

					var differenceInDays = Math.floor(((todayTime - commitTime)/(24*3600*1000)));
					if (differenceInDays == 0) {
						var differenceInHours = Math.floor(((todayTime - commitTime)/(3600*1000)));
						if (differenceInHours == 0) {
							var differenceInMinutes = Math.floor(((todayTime - commitTime)/(600*1000)));
							if (differenceInMinutes == 0) {

								return 'just now';
							}

							return 'about ' + differenceInMinutes + ' minutes ago';
						}

						return 'about ' + differenceInHours + ' hours ago';
					}else if (differenceInDays == 1) {
                        return 'yesterday';
                    }
					return differenceInDays + ' days ago';
				}
			});
		}

		return {
			run: function () {
				_widgetRun(this);
			}
		};

	})();

	$.fn.githubInfoWidget = function(options, callback) {
		this.each(function () {
			var w = new widget($(this), options, callback);
			w.run();
		});
		return this;
	}

})(jQuery);