spectacular/src/factories.coffee

Advanced BDD framework for CoffeeScript and JavaScript

spectacular.factories ||= new spectacular.GlobalizableObject 'build',
                                                             'create',
                                                             'factory',
                                                             'factoryMixin'
spectacular.factories.keepContext = false

spectacular.factories.buildMethodsCache = {}
spectacular.factories.build = (ctor, args=[]) ->
  f = if spectacular.factories.buildMethodsCache[args.length]?
    spectacular.factories.buildMethodsCache[args.length]
  else
    argumentsSignature = ''
    comma = ''
    if args.length > 0
      argumentsSignature = ("arg#{n}" for n in [0..args.length-1]).join(',')
      comma = ','

    spectacular.factories.buildMethodsCache[args.length] = new Function(
      "ctor#{comma}#{argumentsSignature}",
      "return new ctor(#{argumentsSignature});"
    )
  f.apply null, [ctor].concat(args)

class spectacular.factories.Set
  constructor: (@property, @value) ->

  apply: (instance) ->
    if typeof @value is 'function'
      instance[@property] = @value()
    else
      instance[@property] = @value

class spectacular.factories.Trait
  @concern spectacular.Hookable
  @include spectacular.Globalizable
  @include spectacular.HasAncestors
  @extend spectacular.AncestorsProperties

  @followUp 'arguments'
  @followUp 'buildBlock'

  @hook 'build'

  globalizable: 'set createWith build after'.split(/\s+/g)

  constructor: (@name) ->
    @previous = {}
    @setters = []

  set: (property, value) ->
    @setters.push new spectacular.factories.Set property, value

  build: (@ownBuildBlock) ->
  createWith: (@ownArguments...) ->
  after: (hook, block) -> @registerHook hook, block

  applySet: (instance) ->
    @setters.forEach (setter) -> setter.apply instance

class spectacular.factories.Factory extends spectacular.factories.Trait

  globalizable: 'set trait createWith build include after'.split(/\s+/g)

  constructor: (name, @class) ->
    super name
    @traits = {}

  trait: (name, block) ->
    trait = @traits[name] ||= new spectacular.factories.Trait name
    trait.globalize()
    block.call(trait)
    trait.unglobalize()

  buildInstance: (traits, options={}) ->
    args = @getConstructorArguments traits

    instance = if @parent?
      @parent.instanciate args, traits
    else
      @instanciate args, traits

    @applySet instance
    @findTrait(trait).applySet instance for trait in traits
    instance[k] = v for k,v of options

    hooks = @fromTraitAndThis 'buildHooks', traits
    hook.call(instance, instance) for hook in hooks
    instance

  instanciate: (args, traits) ->
    buildBlock = @fromTraitOrThis 'buildBlock', traits
    if buildBlock?
      buildBlock.apply this, [@class].concat(args)
    else
      build @class, args

  fromTraitOrThis: (property, traits) ->
    value = @[property]
    for trait in traits
      traitValue = @findTrait(trait)[property]
      value = traitValue if traitValue?

    value

  fromTraitAndThis: (property, traits) ->
    value = @[property]
    for trait in traits
      traitValue = @findTrait(trait)[property]
      value = value.concat traitValue if traitValue?

    value

  include: (mixins...) ->
    for mixinName in mixins
      mixin = spectacular.factories.mixins[mixinName]
      throw new Error "mixin '#{mixinName}' can't be found" unless mixin?
      mixin.call this, this

  getConstructorArguments: (traits) ->
    args = @fromTraitOrThis 'arguments', traits

    if args? and typeof args[0] is 'function'
      args = args[0].call(spectacular.env.currentExample.context)

    args or []

  findTrait: (traitName) ->
    trait = @traits[traitName] or @parent?.findTrait traitName
    throw new Error "unknown trait #{traitName}" unless trait?
    trait

spectacular.factoriesCache = {}
spectacular.factories.factory = (name, options, block) ->
  cache = spectacular.factoriesCache
  [options, block] = [{}, options] if typeof options is 'function'

  if options.extends?
    parent = cache[options.extends]
    unless parent?
      throw new Error "parent factory '#{options.extends}' can't be found"

    fct = cache[name] ||= new spectacular.factories.Factory name
    fct.parent = parent

  else if options.class?
    fct = cache[name] ||= new spectacular.factories.Factory name, options.class
  else
    fct = cache[name]
    unless fct?
      throw new Error 'no class provided'

  fct.globalize()
  block.call(fct)
  fct.unglobalize()

spectacular.factories.mixins = {}
spectacular.factories.factoryMixin = (name, block) ->
  spectacular.factories.mixins[name] = block

spectacular.factories.create = (name, traits..., options) ->
  throw new Error 'no factory name provided' unless name?
  if typeof options is 'string'
    traits.push options
    options = null

  fct = spectacular.factoriesCache[name]
  throw new Error "missing factory #{name}" unless fct?
  fct.buildInstance(traits, options)