observable.coffee

EE = require 'wildemitter'

class Observable extends EE
    constructor: (initialValue)->
        _latestValue = initialValue
        @_write = (_next_val)=>
            @emit "will-change", _latestValue, (=>
                _latestValue = _next_val
                @emit "changed", _latestValue
            )
        @_read = -> _latestValue
        EE.call(this)

class Model extends EE
    constructor: (props)->

        # inherit from Event emitter
        EE.call(this)

        _undo_stack = []

        self = this

        state_callbacks = {}

        @getState = ->
            _o = {}
            for k,v of state_callbacks
                _o[k] = v._read()
            return _o

        @getHistory = ->
            _undo_stack.concat @getState()

        for k,v of props
            do (k = k ,v = v)->
                o = new Observable(v)
                o.on "will-change", (val, cb)->
                    _undo_stack.push self.getState()
                    cb()

                o.on "changed", ->
                    self.emit "change", self.getState()

                self[k] = (args...)->
                    if args.length > 0
                        o._write(args[0])
                    else
                        o._read()

                state_callbacks[k] = o

z = new Model({x:"1", y:[1,2,3]})

# z.on "change", console.log

z.x("w")

z.y("wow")

console.log  z.getHistory()