{before, after, chainable, cloneNode} = require './helpers'

Instance = require './instance'

# **Context** stores the original `template` elements and is responsible for creating,

# adding and removing template `instances` to match the amount of `models`.

module.exports = class Context

detach = chainable ->

@parent = @el.parentNode

if @parent

@nextSibling = @el.nextSibling

@parent.removeChild @el

attach = chainable ->

if @parent

if @nextSibling

then @parent.insertBefore @el, @nextSibling

else @parent.appendChild @el

constructor: (@el, @Transparency) ->

@template = cloneNode @el

@instances = [new Instance(@el, @Transparency)]

@instanceCache = []

render: \

before(detach) \

after(attach) \

chainable \

(models, directives, options) ->

# Cloning DOM elements is expensive, so save unused template `instances` and reuse them later.

while models.length < @instances.length

@instanceCache.push @instances.pop().remove()

# DOM elements needs to be created before rendering

# https://github.com/leonidas/transparency/issues/94

while models.length > @instances.length

instance = @instanceCache.pop() || new Instance(cloneNode(@template), @Transparency)

@instances.push instance.appendTo(@el)

for model, index in models

instance = @instances[index]

children = []

instance

.prepare(model, children)

.renderValues(model, children)

.renderDirectives(model, index, directives)

.renderChildren(model, children, directives, options)