_ = require('underscore')


class Subscription
    constructor: (@callback, @index, @subscriptionList) ->

    invoke: (args...)->
        @callback(args...)

    dispose: ->
        @subscriptionList.splice(@index, 0)


class Events
    constructor: () ->
        @events = {}

    on: (eventName, listener) ->
        if !@events[eventName]
            !@events[eventName] = []  # new subscription list for this new event

        subscriptionList = @events[eventName]
        subscription = new Subscription(listener, subscriptionList.length, subscriptionList)
        subscriptionList.push(subscription)
        return subscription

    trigger: (eventName, args...) ->
        subscriptionList = @events[eventName] || []
        len = subscriptionList.length

        while len--
            subscription = subscriptionList[len]
            subscription.invoke(args...)

    off: (eventName) ->
        @events[eventName] = []


class Event
    constructor: (@name, @data) ->


_.extend(exports, {
    Event: Event
    Events: Events
    Subscription: Subscription
})