require 'spree_core/action_callbacks'
class Admin::ResourceController < Admin::BaseController
  helper_method :new_object_url, :edit_object_url, :object_url, :collection_url
  before_filter :load_resource

  respond_to :html
  respond_to :js, :except => [:show, :index]

  def flash_message_for(object, event_sym)
    resource_desc  = object.class.model_name.human
    resource_desc += " \"#{object.name}\"" if object.respond_to?(:name)
    I18n.t(event_sym, :resource => resource_desc)  
  end
  
  def new
    respond_with(@object) do |format|
      format.html { render :layout => !request.xhr? }
      format.js { render :layout => false }
    end
  end

  def edit
    respond_with(@object) do |format|
      format.html { render :layout => !request.xhr? }
      format.js { render :layout => false }
    end
  end

  def update
    invoke_callbacks(:update, :before)
    if @object.update_attributes(params[object_name])
      invoke_callbacks(:update, :after)
      flash[:notice] = flash_message_for(@object, :successfully_updated)
      respond_with(@object) do |format|
        format.html { redirect_to location_after_save }
        format.js   { render :layout => false }
      end
    else
      invoke_callbacks(:update, :fails)
      respond_with(@object)
    end
  end

  def create
    invoke_callbacks(:create, :before)
    if @object.save
      invoke_callbacks(:create, :after)
      flash[:notice] = flash_message_for(@object, :successfully_created)
      respond_with(@object) do |format|
        format.html { redirect_to location_after_save }
        format.js   { render :layout => false }
      end
    else
      invoke_callbacks(:create, :fails)
      respond_with(@object)
    end
  end

  def destroy
    invoke_callbacks(:destroy, :before)
    if @object.destroy
      invoke_callbacks(:destroy, :after)
      flash[:notice] = flash_message_for(@object, :successfully_removed)
      respond_with(@object) do |format|
        format.html { redirect_to collection_url }
        format.js   { render :partial => "/admin/shared/destroy" }
      end
    else
      invoke_callbacks(:destroy, :fails)
      respond_with(@object) do |format|
        format.html { redirect_to collection_url }
      end
    end
  end

  protected

  class << self
    attr_accessor :parent_data
    attr_accessor :callbacks

    def belongs_to(model_name, options = {})
      @parent_data ||= {}
      @parent_data[:model_name] = model_name
      @parent_data[:model_class] = model_name.to_s.classify.constantize
      @parent_data[:find_by] = options[:find_by] || :id
    end

    def create
      @callbacks ||= {}
      @callbacks[:create] ||= Spree::ActionCallbacks.new
    end

    def update
      @callbacks ||= {}
      @callbacks[:update] ||= Spree::ActionCallbacks.new
    end

    def destroy
      @callbacks ||= {}
      @callbacks[:destroy] ||= Spree::ActionCallbacks.new
    end
  end

  def model_class
    controller_name.classify.constantize
  end

  def object_name
    controller_name.singularize
  end

  def load_resource
    if member_action?
      @object ||= load_resource_instance
      instance_variable_set("@#{object_name}", @object)
    else
      @collection ||= collection
      instance_variable_set("@#{controller_name}", @collection)
    end
  end

  def load_resource_instance
    if new_actions.include?(params[:action].to_sym)
      build_resource
    elsif params[:id]
      find_resource
    end
  end

  def parent_data
    self.class.parent_data
  end

  def parent
    if parent_data.present?
      @parent ||= parent_data[:model_class].where(parent_data[:find_by] => params["#{parent_data[:model_name]}_id"]).first
      instance_variable_set("@#{parent_data[:model_name]}", @parent)
    else
      nil
    end
  end

  def find_resource
    if parent_data.present?
      parent.send(controller_name).find(params[:id])
    else
      model_class.find(params[:id])
    end
  end

  def build_resource
    if parent_data.present?
      parent.send(controller_name).build(params[object_name])
    else
      model_class.new(params[object_name])
    end
  end

  def collection
    return parent.send(controller_name) if parent_data.present?

    if model_class.respond_to?(:accessible_by) && !current_ability.has_block?(params[:action], model_class)
      model_class.accessible_by(current_ability)
    else
      model_class.scoped
    end
  end

  def location_after_save
    collection_url
  end

  def invoke_callbacks(action, callback_type)
    callbacks = self.class.callbacks || {}
    return if callbacks[action].nil?
    case callback_type.to_sym
      when :before then callbacks[action].before_methods.each {|method| send method }
      when :after  then callbacks[action].after_methods.each  {|method| send method }
      when :fails  then callbacks[action].fails_methods.each  {|method| send method }
    end
  end

  # URL helpers

  def new_object_url(options = {})
    if parent_data.present?
      new_polymorphic_url([:admin, parent, model_class], options)
    else
      new_polymorphic_url([:admin, model_class], options)
    end
  end

  def edit_object_url(object, options = {})
    if parent_data.present?
      send "edit_admin_#{parent_data[:model_name]}_#{object_name}_url", parent, object, options
    else
      send "edit_admin_#{object_name}_url", object, options
    end
  end

  def object_url(object = nil, options = {})
    target = object ? object : @object
    if parent_data.present?
      send "admin_#{parent_data[:model_name]}_#{object_name}_url", parent, target, options
    else
      send "admin_#{object_name}_url", target, options
    end
  end

  def collection_url(options = {})
    if parent_data.present?
      polymorphic_url([:admin, parent, model_class], options)
    else
      polymorphic_url([:admin, model_class], options)
    end
  end

  def collection_actions
    [:index]
  end

  def member_action?
    !collection_actions.include? params[:action].to_sym
  end

  def new_actions
    [:new, :create]
  end
end