(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define([], factory);
    } else if (typeof module === 'object' && module.exports) {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like environments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.uSim = factory();
    }
}(this, function () {
    function uSim() {
        this.time = -Infinity;
        this.simcal = [];
    }

    uSim.prototype.schedule = function (time, object) {
        this.simcal.push({time: time, object: object});
        this.simcal.sort(function (a, b) {
            return a.time - b.time;
        });
    };

    var sentinel = {time: -Infinity, object: null};

    uSim.prototype.peekUntil = function (limit, cb) {
        var record = this.simcal[0] || sentinel,
            recordTime = record.time;
        if (recordTime > limit) record = sentinel;
        else this.simcal.shift();
        if (recordTime > this.time) this.time = recordTime;
        if (cb) cb(record.object); else return record.object;
    };

    uSim.prototype.peek = function (cb) {
        return this.peekUntil(Infinity, cb);
    };

    uSim.prototype.streamUntil = function (limit, cb) {
        while (true) {
            var lastObject = null;
            this.peekUntil(limit, function (object) {
                lastObject = object;
                cb(object);
            });
            if (lastObject == null) break;
        }
    };

    uSim.prototype.stream = function (cb) {
        this.streamUntil(Infinity, cb);
    };

    uSim.prototype.run = function () {
        var self = this;
        this.stream(function (each) {
            each(self);
        });
    };

    return uSim;
}));