DependencyDetection.defer do
  @name = :rails21_view
  
  depends_on do
    !NewRelic::Agent.config[:disable_view_instrumentation] &&
    defined?(ActionController) && defined?(ActionController::Base) && defined?(ActionView::PartialTemplate) && defined?(ActionView::Template) &&
    defined?(Rails::VERSION::STRING) && Rails::VERSION::STRING =~ /^2\.1\./   # Rails 2.1 &&
  end
  
  executes do
    ::NewRelic::Agent.logger.info 'Installing Rails 2.1 View instrumentation'
  end

  executes do
    ActionView::PartialTemplate.class_eval do
      add_method_tracer :render, 'View/#{path_without_extension[%r{^(/.*/)?(.*)$},2]}.#{@view.template_format}.#{extension}/Partial'
    end
    # this is for template rendering, as opposed to partial rendering.
    ActionView::Template.class_eval do
      add_method_tracer :render, 'View/#{(path_without_extension || @view.controller.newrelic_metric_path)[%r{^(/.*/)?(.*)$},2]}.#{@view.template_format}.#{extension}/Rendering'
    end
  end
end

DependencyDetection.defer do
  @name = :old_rails_view
  
  depends_on do
    !NewRelic::Agent.config[:disable_view_instrumentation] &&
    defined?(ActionController) && defined?(ActionController::Base) &&
    defined?(Rails::VERSION::STRING) && Rails::VERSION::STRING =~ /^(1\.|2\.0)/  # Rails 1.* - 2.0 
  end
  
  executes do
    ::NewRelic::Agent.logger.info 'Installing Rails 1.* - 2.0 View instrumentation'
  end
  
  executes do
    ActionController::Base.class_eval do
      add_method_tracer :render, 'View/#{newrelic_metric_path}/Rendering'
    end
    
  end
end

DependencyDetection.defer do
  @name = :rails23_view
  
  depends_on do
    !NewRelic::Agent.config[:disable_view_instrumentation] &&
    defined?(ActionView) && defined?(ActionView::Template) && defined?(ActionView::RenderablePartial) &&
    defined?(Rails::VERSION::STRING) && Rails::VERSION::STRING =~ /^2\.[23]/ 
  end

  executes do
    ::NewRelic::Agent.logger.info 'Installing Rails 2.2 - 2.3 View instrumentation'
  end
  
  executes do    
    ActionView::RenderablePartial.module_eval do
      add_method_tracer :render_partial, 'View/#{path[%r{^(/.*/)?(.*)$},2]}/Partial'
    end
    ActionView::Template.class_eval do
      add_method_tracer :render, 'View/#{path[%r{^(/.*/)?(.*)$},2]}/Rendering'
    end
  end  
end

DependencyDetection.defer do
  @name = :rails2_controller
  
  depends_on do
    defined?(ActionController) && defined?(ActionController::Base)
  end
  
  depends_on do
    defined?(Rails) && Rails::VERSION::MAJOR.to_i == 2
  end
  
  executes do
    ::NewRelic::Agent.logger.info 'Installing Rails 2 Controller instrumentation'
  end
  
  executes do
    ActionController::Base.class_eval do
      include NewRelic::Agent::Instrumentation::ControllerInstrumentation
      
      # Compare with #alias_method_chain, which is not available in
      # Rails 1.1:
      alias_method :perform_action_without_newrelic_trace, :perform_action
      alias_method :perform_action, :perform_action_with_newrelic_trace
      private :perform_action
      
      def self.newrelic_write_attr(attr_name, value) # :nodoc:
        write_inheritable_attribute(attr_name, value)
      end
      
      def self.newrelic_read_attr(attr_name) # :nodoc:
        read_inheritable_attribute(attr_name)
      end
      
      # determine the path that is used in the metric name for
      # the called controller action
      def newrelic_metric_path(action_name_override = nil)
        action_part = action_name_override || action_name
        if action_name_override || self.class.action_methods.include?(action_part)
          "#{self.class.controller_path}/#{action_part}"
        else
          "#{self.class.controller_path}/(other)"
        end
      end
    end
  end
end