require "action_controller/abstract/logger"

module AbstractController
  class AbstractControllerError < StandardError; end
  class DoubleRenderError < AbstractControllerError
    DEFAULT_MESSAGE = "Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like \"redirect_to(...) and return\"."

    def initialize(message = nil)
      super(message || DEFAULT_MESSAGE)
    end
  end  
  
  module Renderer
    depends_on AbstractController::Logger
    
    setup do
      attr_internal :formats
      
      extlib_inheritable_accessor :_view_paths
      
      self._view_paths ||= ActionView::PathSet.new
    end
        
    def _action_view
      @_action_view ||= ActionView::Base.new(self.class.view_paths, {}, self)      
    end
        
    def render(options = {})
      unless response_body.nil?
        raise AbstractController::DoubleRenderError, "OMG"
      end
      
      self.response_body = render_to_body(options)
    end
    
    # Raw rendering of a template to a Rack-compatible body.
    # ====
    # @option _prefix<String> The template's path prefix
    # @option _layout<String> The relative path to the layout template to use
    # 
    # :api: plugin
    def render_to_body(options = {})
      name = options[:_template_name] || action_name
      
      options[:_template] ||= view_paths.find_by_parts(name.to_s, {:formats => formats}, options[:_prefix])
      
      _render_template(options[:_template], options)
    end

    # Raw rendering of a template to a string.
    # ====
    # @option _prefix<String> The template's path prefix
    # @option _layout<String> The relative path to the layout template to use
    # 
    # :api: plugin
    def render_to_string(options = {})
      AbstractController::Renderer.body_to_s(render_to_body(options))
    end

    def _render_template(template, options)
      _action_view._render_template_with_layout(template)
    end
    
    def view_paths() _view_paths end

    # Return a string representation of a Rack-compatible response body.
    def self.body_to_s(body)
      if body.respond_to?(:to_str)
        body
      else
        strings = []
        body.each { |part| strings << part.to_s }
        body.close if body.respond_to?(:close)
        strings.join
      end
    end

    module ClassMethods
      
      def append_view_path(path)
        self.view_paths << path
      end
      
      def view_paths
        self._view_paths
      end
      
      def view_paths=(paths)
        self._view_paths = paths.is_a?(ActionView::PathSet) ?
                            paths : ActionView::Base.process_view_paths(paths)
      end
    end
  end
end