GetJobber/prawnto

require "prawnto/template_handlers/partials"

module Prawnto
  module TemplateHandlers
    class Renderer
      include Partials

      def initialize(view_context, calling_object = nil)
        @view_context = view_context
        @calling_object = calling_object
        set_instance_variables
        @pdf = Prawn::Document.new(@prawnto_options[:prawn]);
      end

      def to_pdf(scope = false, &block)
        @_scope = scope
        instance_eval(&block)
        @pdf.render.html_safe
      end

    private

      def set_instance_variables
        @calling_object ||= @view_context
        copy_instance_variables_from @calling_object

        if @prawnto_options[:instance_variables_from]
          copy_instance_variables_from @prawnto_options[:instance_variables_from]
        end
      end

      def pdf
        @pdf
      end

      # This was removed in Rails 3.1
      def copy_instance_variables_from(object, exclude = [])
        vars = object.instance_variables.map(&:to_s) - exclude.map(&:to_s)
        vars.each { |name| instance_variable_set(name, object.instance_variable_get(name)) }
      end

      def push_instance_variables_to(object, exclude = [])
        vars = instance_variables.map(&:to_s) - exclude.map(&:to_s)
        vars.each { |name| object.instance_variable_set(name, instance_variable_get(name)) }
      end

      # This method is a little hacky with pushing the instance variables back. I would prefer to use bindings, but wasn't having much luck.
      def method_missing(m, *args, &block)
        begin
          super
        rescue
          if pdf.respond_to?(m.to_s)
            pdf.send(m, *args, &block)
          elsif @calling_object.respond_to?(m.to_s)
            push_instance_variables_to @calling_object
            res = @calling_object.send(m, *args, &block)
            copy_instance_variables_from @calling_object
            res
          elsif @calling_object != @view_context and @view_context.respond_to?(m.to_s)
            push_instance_variables_to @view_context
            res = @view_context.send(m, *args, &block)
            copy_instance_variables_from @view_context
            res
          else
            raise
          end
        end
      end

    end
  end
end