module Heimdallr
  module Resource
    extend ActiveSupport::Concern

    module ClassMethods
      attr_reader :model

      def resource_for(model, options={})
        @model = model.to_s.capitalize.constantize

        before_filter :load_all_resources,          only: [ :index ].concat(options[:all] || [])
        before_filter :load_one_resource,           only: [ :show  ].concat(options[:member] || [])
        before_filter :load_referenced_resources,   only: [ :update, :destroy ].concat(options[:collection] || [])
      end
    end

    module InstanceMethods
      def index
      end

      def show
      end

      def new
        render :json => {
          :fields => model.restrictions(security_context).whitelist[:create]
        }
      end

      def create
        model.transaction do
          if params.has_key? model.name.underscore
            scoped_model.new.to_proxy(security_context, :create).
              update_attributes!(params[model.name.underscore])
          else
            @resources.each_with_index do |resource, index|
              scoped_model.new.to_proxy(security_context, :create).
                update_attributes!(params[model.name.underscore.pluralize][index])
            end
          end
        end

        if block_given?
          yield
        else
          render_modified_resources
        end
      end

      def edit
        render :json => {
          :fields => model.restrictions(security_context).whitelist[:update]
        }
      end

      def update
        model.transaction do
          if params.has_key? model.name.underscore
            @resources.first.to_proxy(security_context, :update).
              update_attributes!(params[model.name.underscore])
          else
            @resources.each_with_index do |resource, index|
              resource.to_proxy(security_context, :update).
              update_attributes!(params[model.name.underscore.pluralize][index])
            end
          end
        end

        if block_given?
          yield
        else
          render_modified_resources
        end
      end

      def destroy
        model.transaction do
          @resources.each &:destroy
        end

        render :json => {}, :status => :ok
      end

      protected

      def model
        self.class.model
      end

      def scoped_model
        self.model.scoped
      end

      def load_one_resource
        @resource  = scoped_model.find(params[:id])
      end

      def load_all_resources
        @resources = scoped_model.scoped
      end

      def load_referenced_resources
        @resources = scoped_model.find(params[:id].split(','))
      end

      def render_modified_resources
        render :action => :index
      end
    end
  end
end