require 'corext' # I don't know why this isn't coming from active_support...
require 'responder'
require 'request'


# HACK: built module MimeResponds right into ActionController::Base
class ActionController::Base
  
  
  ### Path to make render, redirect_to, and head public
  # this block (why?) caused exceptions for one app
=begin
  alias_method :old_render, :render
  alias_method :old_redirect_to, :redirect_to
  alias_method :old_head, :head
  
  def render(options = nil, extra_options = {}, &block)
    old_render(options, extra_options, &block)
  end
  
  def redirect_to(options = {}, response_status = {})
    old_redirect_to(options, response_status)
  end
  
  def head(*args)
    old_head(*args)
  end
=end
  
 

  # Defines mimes that are rendered by default when invoking respond_with.
  #
  # Examples:
  #
  #   respond_to :html, :xml, :json
  #
  # All actions on your controller will respond to :html, :xml and :json.
  #
  # But if you want to specify it based on your actions, you can use only and
  # except:
  #
  #   respond_to :html
  #   respond_to :xml, :json, :except => [ :edit ]
  #
  # The definition above explicits that all actions respond to :html. And all
  # actions except :edit respond to :xml and :json.
  #
  # You can specify also only parameters:
  #
  #   respond_to :rjs, :only => :create
  #
  def self.respond_to(*mimes)
    options = mimes.extract_options!

    only_actions   = Array(options.delete(:only))
    except_actions = Array(options.delete(:except))

    mimes.each do |mime|
      mime = mime.to_sym
      mimes_for_respond_to[mime]          = {}
      mimes_for_respond_to[mime][:only]   = only_actions   unless only_actions.empty?
      mimes_for_respond_to[mime][:except] = except_actions unless except_actions.empty?
    end
  end

  # Clear all mimes in respond_to.
  #
  def self.clear_respond_to
    self.mimes_for_respond_to = ActiveSupport::OrderedHash.new
  end


  # included (when this was a module)   
  extlib_inheritable_accessor :responder, :mimes_for_respond_to, :instance_writer => false
  self.responder = ActionController::Responder
  clear_respond_to



  # Without web-service support, an action which collects the data for displaying a list of people
  # might look something like this:
  #
  #   def index
  #     @people = @account.people.find(:all)
  #   end
  #
  # Here's the same action, with web-service support baked in:
  #
  #   def index
  #     @people = @account.people.find(:all)
  #
  #     respond_to do |format|
  #       format.html
  #       format.xml { render :xml => @people.to_xml }
  #     end
  #   end
  #
  # What that says is, "if the client wants HTML in response to this action, just respond as we
  # would have before, but if the client wants XML, return them the list of people in XML format."
  # (Rails determines the desired response format from the HTTP Accept header submitted by the client.)
  #
  # Supposing you have an action that adds a new person, optionally creating their company
  # (by name) if it does not already exist, without web-services, it might look like this:
  #
  #   def create
  #     @company = Company.find_or_create_by_name(params[:company][:name])
  #     @person  = @company.people.create(params[:person])
  #
  #     redirect_to(person_list_url)
  #   end
  #
  # Here's the same action, with web-service support baked in:
  #
  #   def create
  #     company  = params[:person].delete(:company)
  #     @company = Company.find_or_create_by_name(company[:name])
  #     @person  = @company.people.create(params[:person])
  #
  #     respond_to do |format|
  #       format.html { redirect_to(person_list_url) }
  #       format.js
  #       format.xml  { render :xml => @person.to_xml(:include => @company) }
  #     end
  #   end
  #
  # If the client wants HTML, we just redirect them back to the person list. If they want Javascript
  # (format.js), then it is an RJS request and we render the RJS template associated with this action.
  # Lastly, if the client wants XML, we render the created person as XML, but with a twist: we also
  # include the person's company in the rendered XML, so you get something like this:
  #
  #   <person>
  #     <id>...</id>
  #     ...
  #     <company>
  #       <id>...</id>
  #       <name>...</name>
  #       ...
  #     </company>
  #   </person>
  #
  # Note, however, the extra bit at the top of that action:
  #
  #   company  = params[:person].delete(:company)
  #   @company = Company.find_or_create_by_name(company[:name])
  #
  # This is because the incoming XML document (if a web-service request is in process) can only contain a
  # single root-node. So, we have to rearrange things so that the request looks like this (url-encoded):
  #
  #   person[name]=...&person[company][name]=...&...
  #
  # And, like this (xml-encoded):
  #
  #   <person>
  #     <name>...</name>
  #     <company>
  #       <name>...</name>
  #     </company>
  #   </person>
  #
  # In other words, we make the request so that it operates on a single entity's person. Then, in the action,
  # we extract the company data from the request, find or create the company, and then create the new person
  # with the remaining data.
  #
  # Note that you can define your own XML parameter parser which would allow you to describe multiple entities
  # in a single request (i.e., by wrapping them all in a single root node), but if you just go with the flow
  # and accept Rails' defaults, life will be much easier.
  #
  # If you need to use a MIME type which isn't supported by default, you can register your own handlers in
  # environment.rb as follows.
  #
  #   Mime::Type.register "image/jpg", :jpg
  #
  # Respond to also allows you to specify a common block for different formats by using any:
  #
  #   def index
  #     @people = @account.people.find(:all)
  #
  #     respond_to do |format|
  #       format.html
  #       format.any(:xml, :json) { render request.format.to_sym => @people }
  #     end
  #   end
  #
  # In the example above, if the format is xml, it will render:
  #
  #   render :xml => @people
  #
  # Or if the format is json:
  #
  #   render :json => @people
  #
  # Since this is a common pattern, you can use the class method respond_to
  # with the respond_with method to have the same results:
  #
  #   class PeopleController < ApplicationController
  #     respond_to :html, :xml, :json
  #
  #     def index
  #       @people = @account.people.find(:all)
  #       respond_with(@person)
  #     end
  #   end
  #
  # Be sure to check respond_with and respond_to documentation for more examples.
  #
  def respond_to(*mimes, &block)
    raise ArgumentError, "respond_to takes either types or a block, never both" if mimes.any? && block_given?

    if response = retrieve_response_from_mimes(mimes, &block)
      response.call
    end
  end

  # respond_with wraps a resource around a responder for default representation.
  # First it invokes respond_to, if a response cannot be found (ie. no block
  # for the request was given and template was not available), it instantiates
  # an ActionController::Responder with the controller and resource.
  #
  # ==== Example
  #
  #   def index
  #     @users = User.all
  #     respond_with(@users)
  #   end
  #
  # It also accepts a block to be given. It's used to overwrite a default
  # response:
  #
  #   def destroy
  #     @user = User.find(params[:id])
  #     flash[:notice] = "User was successfully created." if @user.save
  #
  #     respond_with(@user) do |format|
  #       format.html { render }
  #     end
  #   end
  #
  # All options given to respond_with are sent to the underlying responder,
  # except for the option :responder itself. Since the responder interface
  # is quite simple (it just needs to respond to call), you can even give
  # a proc to it.
  #
  def respond_with(*resources, &block)
    if response = retrieve_response_from_mimes([], &block)
      options = resources.extract_options!
      options.merge!(:default_response => response)
      (options.delete(:responder) || responder).call(self, resources, options)
    end
  end
  
  attr_accessor :formats

protected

  # Collect mimes declared in the class method respond_to valid for the
  # current action.
  #
  def collect_mimes_from_class_level #:nodoc:
    action = action_name.to_sym

    mimes_for_respond_to.keys.select do |mime|
      config = mimes_for_respond_to[mime]

      if config[:except]
        !config[:except].include?(action)
      elsif config[:only]
        config[:only].include?(action)
      else
        true
      end
    end
  end

  # Collects mimes and return the response for the negotiated format. Returns
  # nil if :not_acceptable was sent to the client.
  #
  def retrieve_response_from_mimes(mimes, &block)
    collector = Collector.new { default_render }
    mimes = collect_mimes_from_class_level if mimes.empty?
    mimes.each { |mime| collector.send(mime) }
    block.call(collector) if block_given?

    if format = request.negotiate_mime(collector.order)
      self.formats = [format.to_sym]
      collector.response_for(format)
    else
      head :not_acceptable
      nil
    end
  end

  class Collector #:nodoc:
    attr_accessor :order

    def initialize(&block)
      @order, @responses, @default_response = [], {}, block
    end

    def any(*args, &block)
      if args.any?
        args.each { |type| send(type, &block) }
      else
        custom(Mime::ALL, &block)
      end
    end
    alias :all :any

    def custom(mime_type, &block)
      mime_type = mime_type.is_a?(Mime::Type) ? mime_type : Mime::Type.lookup(mime_type.to_s)
      @order << mime_type
      @responses[mime_type] ||= block
    end

    def response_for(mime)
      @responses[mime] || @responses[Mime::ALL] || @default_response
    end

    def self.generate_method_for_mime(mime)
      sym = mime.is_a?(Symbol) ? mime : mime.to_sym
      const = sym.to_s.upcase
      class_eval <<-RUBY, __FILE__, __LINE__ + 1
        def #{sym}(&block)                # def html(&block)
          custom(Mime::#{const}, &block)  #   custom(Mime::HTML, &block)
        end                               # end
      RUBY
    end

    Mime::SET.each do |mime|
      generate_method_for_mime(mime)
    end

    def method_missing(symbol, &block)
      mime_constant = Mime.const_get(symbol.to_s.upcase)

      if Mime::SET.include?(mime_constant)
        self.class.generate_method_for_mime(mime_constant)
        send(symbol, &block)
      else
        super
      end
    end

  end
end