module ActiveAdmin
  # This is the class where all the register blocks are instance eval'd
  class ResourceDSL < DSL
    private

    def belongs_to(target, options = {})
      config.belongs_to(target, options)
    end

    # Scope this controller to some object which has a relation
    # to the resource. Can either accept a block or a symbol 
    # of a method to call.
    #
    # Eg:
    #
    #   ActiveAdmin.register Post do
    #     scope_to :current_user
    #   end
    #
    # Then every time we instantiate and object, it would call
    #   
    #   current_user.posts.build
    #
    # By default Active Admin will use the resource name to build a
    # method to call as the association. If its different, you can 
    # pass in the association_method as an option.
    #
    #   scope_to :current_user, :association_method => :blog_posts
    #
    # will result in the following
    # 
    #   current_user.blog_posts.build
    #
    def scope_to(*args, &block)
      options = args.extract_options!
      method = args.first

      config.scope_to = block_given? ? block : method
      config.scope_to_association_method = options[:association_method]
    end

    # Create a scope
    def scope(*args, &block)
      config.scope(*args, &block)
    end

    # Configure the index page for the resource
    def index(options = {}, &block)
      options[:as] ||= :table
      config.set_page_presenter :index, ActiveAdmin::PagePresenter.new(options, &block)
    end

    # Configure the show page for the resource
    def show(options = {}, &block)
      config.set_page_presenter :show, ActiveAdmin::PagePresenter.new(options, &block)
    end

    def form(options = {}, &block)
      config.set_page_presenter :form, ActiveAdmin::PagePresenter.new(options, &block)
    end

    # Configure the CSV format
    #
    # For example:
    #
    #   csv do
    #     column :name
    #     column("Author") { |post| post.author.full_name }
    #   end
    #
    #   csv :separator => ";", :options => { :force_quotes => true } do
    #     column :name
    #   end
    #
    def csv(options={}, &block)
      config.csv_builder = CSVBuilder.new(options, &block)
    end

    # Member Actions give you the functionality of defining both the
    # action and the route directly from your ActiveAdmin registration
    # block.
    #
    # For example:
    #
    #   ActiveAdmin.register Post do
    #     member_action :comments do
    #       @post = Post.find(params[:id]
    #       @comments = @post.comments
    #     end
    #   end
    #
    # Will create a new controller action comments and will hook it up to
    # the named route (comments_admin_post_path) /admin/posts/:id/comments
    #
    # You can treat everything within the block as a standard Rails controller
    # action.
    # 
    def member_action(name, options = {}, &block)
      config.member_actions << ControllerAction.new(name, options)
      title = options.delete(:title)

      controller do
        before_filter(:only => [name]) { @page_title = title } if title
        define_method(name, &block || Proc.new{})
      end
    end

    def collection_action(name, options = {}, &block)
      config.collection_actions << ControllerAction.new(name, options)
      title = options.delete(:title)

      controller do
        before_filter(:only => [name]){ @page_title = title } if title
        define_method(name, &block || Proc.new{})
      end
    end

    # Defined Callbacks
    #
    # == After Build
    # Called after the resource is built in the new and create actions.
    #
    # ActiveAdmin.register Post do
    #   after_build do |post|
    #     post.author = current_user
    #   end
    # end
    #
    # == Before / After Create
    # Called before and after a resource is saved to the db on the create action.
    #
    # == Before / After Update
    # Called before and after a resource is saved to the db on the update action.
    #
    # == Before / After Save
    # Called before and after the object is saved in the create and update action.
    # Note: Gets called after the create and update callbacks
    #
    # == Before / After Destroy
    # Called before and after the object is destroyed from the database.
    #
    delegate :before_build,   :after_build,   :to => :controller
    delegate :before_create,  :after_create,  :to => :controller
    delegate :before_update,  :after_update,  :to => :controller
    delegate :before_save,    :after_save,    :to => :controller
    delegate :before_destroy, :after_destroy, :to => :controller

    # Standard rails filters
    delegate :before_filter, :skip_before_filter, :after_filter, :around_filter, :to => :controller

    # Specify which actions to create in the controller
    #
    # Eg:
    #   
    #   ActiveAdmin.register Post do
    #     actions :index, :show
    #   end
    #
    # Will only create the index and show actions (no create, update or delete)
    delegate :actions, :to => :controller

  end
end