var ObservArray = require("observ-array")
var ObservStruct = require("observ-struct")
var Observ = require("observ")
var uuid = require("uuid")

function createTodo(title) {
  return ObservStruct({
    id: uuid(),
    title: Observ(title || ""),
    completed: Observ(false)
  })
}

var state = ObservStruct({
  todos: ObservArray([
    createTodo("some todo"),
    createTodo("some other todo")
  ])
})

state(function (currState) {
  // currState.todos is a plain javascript todo
  // currState.todos[0] is a plain javascript value
  currState.todos.forEach(function (todo, index) {
    console.log("todo", todo.title, index)
  })
})

state.todos.get(0).title.set("some new title")
state.todos.push(createTodo("another todo"))

var array = ObservArray([ Observ("foo"), Observ("bar") ])

var removeListener = array(handleChange)

array.transaction(function(rawList) {
  rawList.push(Observ("foobar"))
  rawList.splice(1, 1, Observ("baz"), Observ("bazbar"))
  rawList.unshift(Observ("foobaz"))
  rawList[6] = Observ("foobarbaz")
})

function handleChange(value) {
  // this will only be called once
  // changes are batched into a single diff
  value._diff //= [ [1,1,"baz","bazbar","foobar", , "foobarbaz"],
              //    [0,0,"foobaz"] ]
}