neft/src/document/use.coffee

JavaScript. Everywhere.

'use strict'

utils = require 'src/utils'
assert = require 'src/assert'
log = require 'src/log'

assert = assert.scope 'View.Use'
log = log.scope 'View', 'Use'

module.exports = (File) -> class Use
    @__name__ = 'Use'
    @__path__ = 'File.Use'

    JSON_CTOR_ID = @JSON_CTOR_ID = File.JSON_CTORS.push(Use) - 1

    i = 1
    JSON_NODE = i++
    JSON_ARGS_LENGTH = @JSON_ARGS_LENGTH = i

    @_fromJSON = (file, arr, obj) ->
        unless obj
            node = file.node.getChildByAccessPath arr[JSON_NODE]
            obj = new Use file, node
        obj

    visibilityChangeListener = ->
        if @file.isRendered and not @isRendered
            @render()

    attrsChangeListener = (name) ->
        if name is 'neft:fragment'
            @name = @node.attrs['neft:fragment']

            if @isRendered
                @revert()
                @render()
        return

    queue = []
    queuePending = false

    runQueue = ->
        style = queue.shift()
        file = queue.shift()

        if style.isRendered
            style.renderFragment file

        if queue.length
            requestAnimationFrame runQueue
        else
            queuePending = false
        return

    constructor: (@file, @node) ->
        assert.instanceOf @file, File
        assert.instanceOf @node, File.Element

        @name = @node.attrs['neft:fragment']
        @usedFragment = null
        @isRendered = false

        @node.onVisibleChange visibilityChangeListener, @
        @node.onAttrsChange attrsChangeListener, @

        `//<development>`
        if @constructor is Use
            Object.preventExtensions @
        `//</development>`

    `//<development>`
    usesWithNotFoundFragments = []
    logUsesWithNoFragments = ->
        while useElem = usesWithNotFoundFragments.pop()
            unless useElem.usedFragment
                log.warn "neft:fragment '#{useElem.name}' can't be find in file '#{useElem.file.path}'"
        return
    `//</development>`

    render: (file) ->
        assert.instanceOf file, File if file?

        return unless @node.visible

        if @isRendered
            @revert()

        @isRendered = true

        useAsync = utils.isClient
        useAsync &&= @node.attrs.has 'neft:async'
        useAsync &&= @node.attrs['neft:async'] isnt false
        if useAsync
            queue.push this, file
            unless queuePending
                requestAnimationFrame runQueue
                queuePending = true
        else
            @renderFragment file

        return

    renderFragment: (file) ->
        fragment = @file.fragments[@name]
        if not file and not fragment and not File._files[@name]
            `//<development>`
            # if usesWithNotFoundFragments.push(@) is 1
            #   setTimeout logUsesWithNoFragments
            `//</development>`
            return

        usedFragment = file or File.factory(fragment or @name)

        if file
            file.parentUse?.detachUsedFragment()

        unless usedFragment.isClone
            usedFragment = usedFragment.clone()

        unless usedFragment.isRendered
            usedFragment = usedFragment.render null, @file.root, @

        usedFragment.node.parent = @node
        @usedFragment = usedFragment

        # signal
        usedFragment.parentUse = @
        usedFragment.onReplaceByUse.emit @
        File.emitNodeSignal usedFragment, 'neft:onReplaceByUse', @

        return

    revert: ->
        return unless @isRendered

        # destroy used fragment
        if @usedFragment
            @usedFragment.revert().destroy()

        @isRendered = false
        return

    detachUsedFragment: ->
        assert.isDefined @usedFragment

        @usedFragment.node.parent = null
        @usedFragment.parentUse = null
        @usedFragment = null
        return

    clone: (original, file) ->
        node = original.node.getCopiedElement @node, file.node

        new Use file, node

    toJSON: (key, arr) ->
        unless arr
            arr = new Array JSON_ARGS_LENGTH
            arr[0] = JSON_CTOR_ID
        arr[JSON_NODE] = @node.getAccessPath @file.node
        arr