require "make_restful/version"

module MakeRestful
  extend ActiveSupport::Concern
  extend ActiveSupport::Autoload

  autoload :ClassMethods
  autoload :ControllerAdditions

  included do

    cattr_accessor :allowed_methods, :allowed_formats, :finder, :pagination, :resource_class

    resource name.underscore.gsub(/(.*)_controller/,'\1').singularize
    allow_formats :json, :jsonp, :xml
    allow_methods :index, :get, :put, :post, :delete
    find_by :id

    ####################################
    ## RESTful Methods
    ####################################

  end

  # GET /resources
  def index
    head :method_not_allowed and return unless allow_method? :index, :list
    @response = { :"#{self.class.resource_name}" => @collection }
    @response.merge!(
      {
        current_page: results.current_page,
        per_page: results.per_page,
        total_entries: results.total_entries,
      }
    ) if self.class.pagination && !params.has_key?(:all)

    if @collection.empty?
      @response = { error: 'no results found' }
      @status = :not_found
    end

    render_formats
  end

  # POST /resources
  def create
    head :method_not_allowed and return unless allow_method? :post, :create
    @response = @resource.create
    render_formats
  end

  # PUT /resources/:id
  def show
    head :method_not_allowed and return unless allow_method? :get, :show
    @response = @instance
    unless @response
      @response = { error: 'record_not_found' }
      @status = :not_found
    end
    render_formats
  end

  # PUT /resources/:id
  def update
    head :method_not_allowed and return unless allow_method? :put, :patch, :update
    @response = @instance.update_attributes(params[@resource.to_s.underscore])
    render_formats
  end

  # DELETE /resources/:id
  def destroy
    head :method_not_allowed and return unless allow_method? :delete, :destroy
    @response = @instance.destroy
    render_formats
  end

  # OPTIONS /resources
  def spec
    @response = {
      supports: self.class.supported_methods,
      specification: ( @resource.specification if @resource.respond_to?(:specification) ) || "No Specification"
    }
    render_formats
  end

  private

  ## Rendering

  def render_formats
    respond_to do |format|
      format.json { render json: @response, status: @status, callback: ( params[:callback] if allow_format? :jsonp )} if allow_format? :json, :jsonp
      format.xml { render xml: @response, status: @status } if allow_format? :xml
      format.html { render status: @status } if allow_format? :html
    end
  end

  # Is a format allowed?

  def allow_format?(*formats)
    true if formats.map(&:to_sym).select { |i| allowed_formats.map(&:to_sym).include? i }.present?
  end

  # Is a method allowed?

  def allow_method?(*methods)
    true if methods.map(&:to_sym).select { |i| allowed_methods.map(&:to_sym).include? i }.present?
  end

  def load_resource
    @resource = self.class.resource_class
    @resource.params = params.except(:action, :controller, :id) if @resource.respond_to?(:params=)
  end

  def load_collection
    @collection = if self.class.pagination && !params.has_key?(:all)
      @resource.paginate page: params[:page], per_page: (params[:per_page] || self.class.pagination[:per_page] || 25)
    else
      @resource.all
    end
    eval("@#{self.class.resource_name} = @collection")
  end

  def load_instance
    @instance = eval "@#{self.class.instance_name} = #{@resource.send(:"find_by_#{self.class.finder}", params[:id])}" if params[:id] && @resource.respond_to?(:find)
  end

  def resource
    @resource
  end

  def instance
    @instance
  end

  def collection
    @collection
  end

end