add dmail notices for mentions in forum posts

app/logical/d_text.rb

@@ -2,6 +2,8 @@ require 'cgi'
 require 'uri'
 
 class DText
+  MENTION_REGEXP = /(?:^| )@\S+/
+  
   def self.u(string)
     CGI.escape(string)
   end
@@ -36,7 +38,7 @@ class DText
     str.gsub!(/&/, "&")
     str.gsub!(/</, "&lt;")
     str.gsub!(/>/, "&gt;")
-    str.gsub!(/(?:^| )@\S+/) do |name| 
+    str.gsub!(MENTION_REGEXP) do |name| 
       if name =~ /([:;,.!?\)\]<>])$/
         name.chop!
         ch = $1

app/logical/mentionable.rb

@@ -0,0 +1,41 @@
+module Mentionable
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    # options:
+    # - message_field
+    # - user_field
+    def mentionable(options = {})
+      @mentionable_options = options
+
+      after_create :queue_mention_messages
+    end
+
+    def mentionable_option(key)
+      @mentionable_options[key]
+    end
+  end
+
+  def queue_mention_messages
+    title = self.class.mentionable_option(:title)
+    from_id = read_attribute(self.class.mentionable_option(:user_field))
+    text = read_attribute(self.class.mentionable_option(:message_field))
+
+    text.scan(DText::MENTION_REGEXP).each do |mention|
+      mention.gsub!(/(?:^\s*@)|(?:[:;,.!?\)\]<>]$)/, "")
+      user = User.find_by_name(mention)
+      body = self.class.mentionable_option(:body).call(self, user.name)
+
+      if user
+        dmail = Dmail.new(
+          from_id: from_id,
+          to_id: user.id,
+          title: title,
+          body: body
+        )
+        dmail.owner_id = user.id
+        dmail.save
+      end
+    end
+  end
+end

app/models/forum_post.rb

@@ -1,4 +1,6 @@
 class ForumPost < ActiveRecord::Base
+  include Mentionable
+
   attr_accessible :body, :topic_id, :as => [:member, :builder, :janitor, :gold, :platinum, :contributor, :admin, :moderator, :default]
   attr_accessible :is_locked, :is_sticky, :is_deleted, :as => [:admin, :moderator]
   attr_readonly :topic_id
@@ -16,6 +18,12 @@ class ForumPost < ActiveRecord::Base
   validate :topic_id_not_invalid
   before_destroy :validate_topic_is_unlocked
   after_save :delete_topic_if_original_post
+  mentionable(
+    :message_field => :body, 
+    :user_field => :creator_id, 
+    :title => "You were mentioned in a forum topic",
+    :body => lambda {|rec, user_name| "You were mentioned in the forum topic \"#{rec.topic.title}\":#{Danbooru.config.hostname}/forum_topics/#{rec.topic_id}?page=#{rec.forum_topic_page}\n\n<hr>\n\n#{ActionController::Base.helpers.excerpt(rec.body, user_name)}"}
+  )
 
   module SearchMethods
     def body_matches(body)

test/unit/forum_post_test.rb

@@ -14,6 +14,22 @@ class ForumPostTest < ActiveSupport::TestCase
       CurrentUser.ip_addr = nil
     end
 
+    context "that mentions a user" do
+      setup do
+        @user2 = FactoryGirl.create(:user)
+        @post = FactoryGirl.build(:forum_post, :topic_id => @topic.id, :body => "Hey @#{@user2.name} check this out!")
+      end
+
+      should "create a dmail" do
+        assert_difference("Dmail.count", 1) do
+          @post.save
+        end
+
+        dmail = Dmail.last
+        assert_equal("You were mentioned in the forum topic \"#{@topic.title}\":#{Danbooru.config.hostname}/forum_topics/#{@topic.id}?page=1\n\n<hr>\n\nHey @#{@user2.name} check this out!", dmail.body)
+      end
+    end
+
     context "that belongs to a topic with several pages of posts" do
       setup do
         Danbooru.config.stubs(:posts_per_page).returns(3)