module Facebooker
  module Rails
    # ActionMailer like module for publishing Facbook messages
    # 
    # To use, create a subclass and define methods
    # Each method should start by calling send_as to specify the type of message
    # Valid options are  :email and :notification, :user_action, :profile, :ref, :publish_stream
    # 
    #
    # Below is an example of each type
    #
    #   class TestPublisher < Facebooker::Rails::Publisher
    #     # The new message templates are supported as well
    #     # First, create a method that contains your templates:
    #     # You may include multiple one line story templates and short story templates
    #     # but only one full story template
    #     #  Your most specific template should be first
    #     #
    #     # Before using, you must register your template by calling register. For this example
    #     #  You would call TestPublisher.register_publish_action
    #     #  Registering the template will store the template id returned from Facebook in the 
    #     # facebook_templates table that is created when you create your first publisher
    #     def publish_action_template
    #       one_line_story_template "{*actor*} did stuff with {*friend*}"
    #       one_line_story_template "{*actor*} did stuff"
    #       short_story_template "{*actor*} has a title {*friend*}", render(:partial=>"short_body")
    #       short_story_template "{*actor*} has a title", render(:partial=>"short_body")
    #       full_story_template "{*actor*} has a title {*friend*}", render(:partial=>"full_body")    
    #       action_links action_link("My text {*template_var*}","{*link_url*}")
    #     end
    #
    #     # To send a registered template, you need to create a method to set the data
    #     # The publisher will look up the template id from the facebook_templates table
    #     def publish_action(f)
    #       send_as :user_action
    #       from f
    #       story_size SHORT # or ONE_LINE or FULL
    #       data :friend=>"Mike"
    #     end
    #   
    #  
    #     # Provide a from user to send a general notification
    #     # if from is nil, this will send an announcement
    #     def notification(to,f)
    #       send_as :notification
    #       recipients to
    #       from f
    #       fbml "Not"
    #     end
    #  
    #     def email(to,f)
    #       send_as :email
    #       recipients to
    #       from f
    #       title "Email"
    #       fbml 'text'
    #       text fbml
    #     end
    #     # This will render the profile in /users/profile.fbml.erb
    #     #   it will set @user to user_to_update in the template
    #     #  The mobile profile will be rendered from the app/views/test_publisher/_mobile.erb
    #     #   template
    #     def profile_update(user_to_update,user_with_session_to_use)
    #       send_as :profile
    #       from user_with_session_to_use
    #       recipients user_to_update
    #       profile render(:file=>"users/profile.fbml.erb",:assigns=>{:user=>user_to_update})
    #       profile_action "A string"
    #       mobile_profile render(:partial=>"mobile",:assigns=>{:user=>user_to_update})
    #   end
    #
    #     #  Update the given handle ref with the content from a
    #     #   template
    #     def ref_update(user)
    #       send_as :ref
    #       from user
    #       fbml render(:file=>"users/profile",:assigns=>{:user=>user_to_update})
    #       handle "a_ref_handle"
    #   end
    #
    #     #  Publish a post into the stream on the user's Wall and News Feed.
    #     def publish_stream(user_with_session_to_use, user_to_update, params)
    #       send_as :publish_stream
    #       from  user_with_session_to_use
    #       target user_to_update
    #       attachment params[:attachment]
    #       message params[:message]
    #       action_links params[:action_links]
    #     end
    #
    #
    # To send a message, use ActionMailer like semantics
    #    TestPublisher.deliver_action(@user)
    #
    # For testing, you may want to create an instance of the underlying message without sending it
    #  TestPublisher.create_action(@user)
    # will create and return an instance of Facebooker::Feeds::Action
    #
    # Publisher makes many helpers available, including the linking and asset helpers
    class Publisher

      #story sizes from the Facebooker API
      ONE_LINE=1
      SHORT=2
      FULL=4

      def initialize
        @from                 = nil
        @full_story_template  = nil
        @recipients           = nil
        @controller           = PublisherController.new(self)
      end

      def self.default_url_options
        {:host => Facebooker.canvas_server_base + Facebooker.facebook_path_prefix}
      end

      def default_url_options
        self.class.default_url_options
      end

      # use facebook options everywhere
      def request_comes_from_facebook?
        true
      end

      class FacebookTemplate < ::ActiveRecord::Base
        cattr_accessor :template_cache
        self.template_cache = {}

        def self.inspect(*args)
          "FacebookTemplate"
        end

        def template_changed?(hash)
          if respond_to?(:content_hash)
            content_hash != hash 
          else
            false
          end
        end
        
        def deactivate
          Facebooker::Session.create.deactivate_template_bundle_by_id(self.bundle_id)
          return true
        rescue Facebooker::Session::TemplateBundleInvalid => e
          return false
        end

        
        
        class << self
          
          def register(klass,method)
            publisher = setup_publisher(klass,method)            
            template_id = Facebooker::Session.create.register_template_bundle(publisher.one_line_story_templates,publisher.short_story_templates,publisher.full_story_template,publisher.action_links)
            template = find_or_initialize_by_template_name(template_name(klass,method))
            template.deactivate if template.bundle_id  # deactivate old templates to avoid exceeding templates/app limit
            template.bundle_id = template_id
            template.content_hash = hashed_content(klass,method) if template.respond_to?(:content_hash)
            template.save!
            cache(klass,method,template)
            template
          end
          
          def for_class_and_method(klass,method)
            find_cached(klass,method) 
          end
          def bundle_id_for_class_and_method(klass,method)
            for_class_and_method(klass,method).bundle_id
          end
          
          def cache(klass,method,template)
            template_cache[template_name(klass,method)] = template
          end
          
          def clear_cache!
            self.template_cache = {}
          end
          
          def find_cached(klass,method)
            template_cache[template_name(klass,method)] || find_in_db(klass,method)
          end
          
          def find_in_db(klass,method)
            template = find_by_template_name(template_name(klass,method))
            
            if template.nil? || template.template_changed?(hashed_content(klass, method))
              template = register(klass,method)
            end
            template
          end
          
          def setup_publisher(klass,method)
            publisher = klass.new
            publisher.send method + '_template'
            publisher
          end
          
          def hashed_content(klass, method)
            publisher = setup_publisher(klass,method)
            # sort the Hash elements (in the short_story and full_story) before generating MD5
            Digest::MD5.hexdigest [publisher.one_line_story_templates,
               (publisher.short_story_templates and publisher.short_story_templates.collect{|ss| ss.to_a.sort_by{|e| e[0].to_s}}),
               (publisher.full_story_template and publisher.full_story_template.to_a.sort_by{|e| e[0].to_s})
               ].to_json
          end

          def template_name(klass,method)
            "#{Facebooker.api_key}: #{klass.name}::#{method}"
          end
        end
      end

      class_inheritable_accessor :master_helper_module
      attr_accessor :one_line_story_templates, :short_story_templates
      attr_writer :action_links

      cattr_accessor :skip_registry
      self.skip_registry = false


      class InvalidSender < StandardError; end
      class UnknownBodyType < StandardError; end
      class UnspecifiedBodyType < StandardError; end
      class Email
        attr_accessor :title
        attr_accessor :text
        attr_accessor :fbml
      end
  
      class Notification
        attr_accessor :fbml
      end
  
      class Profile
        attr_accessor :profile
        attr_accessor :profile_action
        attr_accessor :mobile_profile
        attr_accessor :profile_main
      end
      class Ref
        attr_accessor :handle
        attr_accessor :fbml
      end
      class UserAction
        attr_accessor :data
        attr_reader   :target_ids
        attr_accessor :body_general
        attr_accessor :template_id
        attr_accessor :template_name
        attr_accessor :story_size

        def target_ids=(val)
          @target_ids = val.is_a?(Array) ? val.join(",") : val
        end

        def data_hash
          data||{}
        end
      end

      class PublishStream
        attr_accessor :target
        attr_accessor :attachment
        attr_accessor :action_links
        attr_accessor :message
      end

      cattr_accessor :ignore_errors
      attr_accessor :_body

      def recipients(*args)
        if args.size==0
          @recipients
        else
          @recipients=args.first
        end
      end
      
      def from(*args)
        if args.size==0
          @from
        else
          @from=args.first
        end        
      end


      def send_as(option)
        self._body=case option
        when :action
          Facebooker::Feed::Action.new
        when :story
          Facebooker::Feed::Story.new
        when :templatized_action
          Facebooker::Feed::TemplatizedAction.new
        when :notification
          Notification.new
        when :email
          Email.new
        when :profile
          Profile.new
        when :ref
          Ref.new
        when :user_action
          UserAction.new
        when :publish_stream
          PublishStream.new
        else
          raise UnknownBodyType.new("Unknown type to publish")
        end
      end
      
      def full_story_template(title=nil,body=nil,params={})
        if title.nil?
          @full_story_template
        else
          @full_story_template=params.merge(:template_title=>title, :template_body=>body)
        end
      end
      
      def one_line_story_template(str)
        @one_line_story_templates ||= []
        @one_line_story_templates << str
      end

      def short_story_template(title,body,params={})
        @short_story_templates ||= []
        @short_story_templates << params.merge(:template_title=>title, :template_body=>body)
      end

      def action_links(*links)
        if links.blank?
          @action_links
        else
          @action_links = links
        end
      end
      
      def method_missing(name,*args)
        if args.size==1 and self._body.respond_to?("#{name}=")
          self._body.send("#{name}=",*args)
        elsif self._body.respond_to?(name)
          self._body.send(name,*args)
        else
          super
        end
      end
      
      # work around the fact that facebook cares about the order of the keys in the hash
      class ImageHolder
        attr_accessor :src,:href
        def initialize(src,href)
          self.src=src
          self.href=href
        end

        def ==(other)
          self.src == other.src && self.href == other.href
        end

        def to_json(*args)
          "{\"src\":#{src.to_json}, \"href\":#{href.to_json}}"
        end
      end
      
      def image(src,target)
        ImageHolder.new(image_path(src),target.respond_to?(:to_str) ? target : url_for(target))
      end
           
      def action_link(text,target)
        {:text=>text, :href=>target}
      end
  
      def requires_from_user?(from,body)
        ! (announcement_notification?(from,body) or ref_update?(body) or profile_update?(body))
      end
      
      def profile_update?(body)
        body.is_a?(Profile)
      end
      
      def ref_update?(body)
        body.is_a?(Ref)
      end
  
      def announcement_notification?(from,body)
        from.nil? and body.is_a?(Notification)
      end
      
      def send_message(method)
        @recipients = @recipients.is_a?(Array) ? @recipients : [@recipients]
        if from.nil? and @recipients.size==1 and requires_from_user?(from,_body)
          @from = @recipients.first
        end
        # notifications can 
        # omit the from address
        raise InvalidSender.new("Sender must be a Facebooker::User") unless from.is_a?(Facebooker::User) || !requires_from_user?(from,_body)
        case _body
        when Facebooker::Feed::TemplatizedAction,Facebooker::Feed::Action
          from.publish_action(_body)
        when Facebooker::Feed::Story
          @recipients.each {|r| r.publish_story(_body)}
        when Notification
          (from.nil? ? Facebooker::Session.create : from.session).send_notification(@recipients,_body.fbml)
        when Email
          from.session.send_email(@recipients, 
                                             _body.title, 
                                             _body.text, 
                                             _body.fbml)
        when Profile
         # If recipient and from aren't the same person, create a new user object using the
         # userid from recipient and the session from from
         @from = Facebooker::User.new(Facebooker::User.cast_to_facebook_id(@recipients.first),Facebooker::Session.create) 
         @from.set_profile_fbml(_body.profile, _body.mobile_profile, _body.profile_action, _body.profile_main)
        when Ref
          Facebooker::Session.create.server_cache.set_ref_handle(_body.handle,_body.fbml)
        when UserAction
          @from.session.publish_user_action(_body.template_id,_body.data_hash,_body.target_ids,_body.body_general,_body.story_size)
        when PublishStream
         @from.publish_to(_body.target, {:attachment => _body.attachment, :action_links => @action_links, :message => _body.message })
        else
          raise UnspecifiedBodyType.new("You must specify a valid send_as")
        end
      end

      # nodoc
      # needed for actionview
      def logger
        RAILS_DEFAULT_LOGGER
      end

      # nodoc
      # delegate to action view. Set up assigns and render
      def render(opts)
        opts = opts.dup
        body = opts.delete(:assigns) || {}
        initialize_template_class(body.dup.merge(:controller=>self)).render(opts)
      end


      def initialize_template_class(assigns)
        template_root = "#{RAILS_ROOT}/app/views"
	      controller_root = File.join(template_root,self.class.controller_path)
        #only do this on Rails 2.1
	      if ActionController::Base.respond_to?(:append_view_path)
  	      # only add the view path once
  	      unless ActionController::Base.view_paths.include?(controller_root)
	          ActionController::Base.append_view_path(controller_root) 
	          ActionController::Base.append_view_path(controller_root+"/..") 
	        end
          view_paths = ActionController::Base.view_paths
        else
          view_paths = [template_root, controller_root]
	      end
        returning ActionView::Base.new(view_paths, assigns, self) do |template|
          template.controller=self
          template.extend(self.class.master_helper_module)
          def template.request_comes_from_facebook?
            true
          end
        end
      end
  
      
      self.master_helper_module = Module.new
      self.master_helper_module.module_eval do
        # url_helper delegates to @controller, 
        # so we need to define that in the template
        # we make it point to the publisher
        include ActionView::Helpers::UrlHelper
        include ActionView::Helpers::TextHelper
        include ActionView::Helpers::TagHelper
        include ActionView::Helpers::FormHelper
        include ActionView::Helpers::FormTagHelper
        include ActionView::Helpers::AssetTagHelper
        include ActionView::Helpers::NumberHelper
        include Facebooker::Rails::Helpers
        
        #define this for the publisher views
        def protect_against_forgery?
          @paf ||= ActionController::Base.new.send(:protect_against_forgery?)
        end
        
        # url_for calls in publishers tend to want full paths
        def url_for(options = {})
          super(options.kind_of?(Hash) ? {:only_path => false}.update(options) : options)
        end
      end
      ActionController::Routing::Routes.named_routes.install(self.master_helper_module)
      include self.master_helper_module
      class <<self

        def register_all_templates_on_all_applications
          Facebooker.with_all_applications do
            puts "Registering templates for #{Facebooker.api_key}"
            register_all_templates
          end
        end
        
        def register_all_templates
          all_templates = instance_methods.grep(/_template$/) - %w(short_story_template full_story_template one_line_story_template) 
          all_templates.each do |template|
            template_name=template.sub(/_template$/,"")
            puts "Registering #{template_name}"
            send("register_"+template_name)
          end
        end
        
        def unregister_inactive_templates
          session = Facebooker::Session.create
          active_template_ids = FacebookTemplate.all.map(&:bundle_id)
          all_template_ids = session.active_template_bundles.map {|t| t["template_bundle_id"]}
          (all_template_ids - active_template_ids).each do |template_bundle_id|
            session.deactivate_template_bundle_by_id(template_bundle_id)
          end
        end
        
        def method_missing(name,*args)
          should_send = false
          method = ''
          if md = /^create_(.*)$/.match(name.to_s)
            method = md[1]
          elsif md = /^deliver_(.*)$/.match(name.to_s)
            method = md[1]
            should_send = true            
          elsif md = /^register_(.*)$/.match(name.to_s)
            return FacebookTemplate.register(self, md[1])
          else
            super
          end
      
          #now create the item
          (publisher=new).send(method,*args)
          case publisher._body
          when UserAction
            publisher._body.template_name = method
            publisher._body.template_id ||= FacebookTemplate.bundle_id_for_class_and_method(self,method)
          end
          
          should_send ? publisher.send_message(method) : publisher._body
        end
        
        def controller_path
          self.to_s.underscore
        end
        
        def helper(*args)
          args.each do |arg|
            case arg
            when Symbol,String
              add_template_helper("#{arg.to_s.camelcase}Helper".constantize)
            when Module
              add_template_helper(arg)
            end
          end
        end

        def add_template_helper(helper_module) #:nodoc:
          master_helper_module.send :include,helper_module
          include master_helper_module
        end


        def inherited(child)
          super
          child.master_helper_module=Module.new
          child.master_helper_module.__send__(:include,self.master_helper_module)
          child.send(:include, child.master_helper_module)
          FacebookTemplate.clear_cache!
        end

      end
      class PublisherController
        include Facebooker::Rails::Publisher.master_helper_module
        include ActionController::UrlWriter
        
        def initialize(source)
          self.class.url_option_source = source
        end

        class << self
          attr_accessor :url_option_source
          alias :old_default_url_options :default_url_options
          def default_url_options(*args)
            url_option_source.default_url_options(*args)
          end
        end

      end

    end
  end
end