// time in seconds
// genitive - использовать ли родительный падеж (true / false)
(function (){
    var units = [
        { name: "second", limit: 60, in_seconds: 1 },
        { name: "minute", limit: 3600, in_seconds: 60 },
        { name: "hour", limit: 86400, in_seconds: 3600  },
        { name: "day", limit: 604800, in_seconds: 86400 },
        { name: "week", limit: 2629743, in_seconds: 604800  },
        { name: "month", limit: 31556926, in_seconds: 2629743 },
        { name: "year", limit: null, in_seconds: 31556926 }
    ];
    var ru_locale = {
        second: {name: 'секунд', one: ['а', 'у'], few: 'ы',    many: ''},
        minute: {name: 'минут',  one: ['а', 'у'], few: 'ы',    many: ''},
        hour:   {name: 'час',    one: '',         few: 'а',    many: 'ов'},
        day:    {name: '',       one: 'день',     few: 'дня',  many: 'дней'},
        week:   {name: 'недел',  one: ['я', 'ю'], few: 'и',    many: 'ь'},
        month:  {name: 'месяц',  one: '',         few: 'а',    many: 'ев'},
        year:   {name: '',       one: 'год',      few: 'года', many: 'лет'}
    };
    var locale = function (name, number, genitive) {
        var e;
        if (number > 10 && number < 20)
            e = 'many';
        else {
            number = number % 10;
            e = number == 1 ? 'one' : (number < 5 && number > 1 ? 'few' : 'many');
        }
        var ends = ru_locale[name][e];
        if (typeof ends !== 'string')
            ends = ends[genitive ? 1 : 0];
        return ru_locale[name].name + ends;
    };
    window.timeAgo = function (time, genitive) {
        genitive = genitive || false;

        var diff = (new Date() - new Date(time * 1000)) / 1000;
        if (diff < 5) return "только что";

        var i = 0, unit;
        while (unit = units[i++]) {
            if (diff < unit.limit || !unit.limit) {
                diff = Math.floor(diff / unit.in_seconds);
                return diff + " " + locale(unit.name, diff, genitive);
            }
        }
    }
})();