module.exports = function (onDone) {
    this.events = []
    this.onDone = onDone

    return {
        searchEvent: function(eventName) {
            return this.events.findIndex((el, index) => (el.name === eventName))
        },
        addEvent: function(eventName, eventCount = 0) {
            this.events.push({name: eventName, count: eventCount});
            return eventIndex = this.events.length - 1;
        },
        register: function(eventName, eventCount = 0) {
            var eventIndex = this.searchEvent(eventName);
            eventIndex = (eventIndex === -1) ? this.addEvent(eventName) : eventIndex;
            this.events[eventIndex].count += eventCount;
        },
        check: function(eventName) {
            var eventIndex = this.searchEvent(eventName);
            if (eventIndex !== -1) {
                this.events[eventIndex].count -= 1;
                if (this.events[eventIndex].count === 0) {
                    this.events.splice(eventIndex, 1);
                }
                if (this.events.length === 0) {
                    this.onDone && this.onDone();
                }
            }
        },
        update: function(onDone) {
            this.events = [];
            this.onDone = onDone;
        }
    }
}