fixes #2191

app/logical/daily_maintenance.rb

@@ -11,5 +11,6 @@ class DailyMaintenance
     UserUploadClamper.new.clamp_all!
     TagSubscription.process_all
     ApiCacheGenerator.new.generate_tag_cache
+    ForumSubscription.process_all!
   end
 end

app/mailers/user_mailer.rb

@@ -1,4 +1,5 @@
 class UserMailer < ActionMailer::Base
+  add_template_helper ApplicationHelper
   default :from => Danbooru.config.contact_email, :content_type => "text/html"
 
   def dmail_notice(dmail)
@@ -13,4 +14,10 @@ class UserMailer < ActionMailer::Base
   def upgrade_fail(email)
     mail(:to => "#{user.name} <#{email}>", :subject => "#{Danbooru.config.app_name} account upgrade")
   end
+
+  def forum_notice(user, forum_topic, forum_posts)
+    @forum_topic = forum_topic
+    @forum_posts = forum_posts
+    mail(:to => "#{user.name} <#{user.email}>", :subject => "#{Danbooru.config.app_name} forum topic #{forum_topic.title} updated")
+  end
 end

app/models/forum_post.rb

@@ -1,5 +1,5 @@
 class ForumPost < ActiveRecord::Base
-  attr_accessible :body, :topic_id, :as => [:member, :builder, :janitor, :gold, :platinum, :contributor, :admin, :moderator, :default]
+  attr_accessible :body, :topic_id, :receive_email_notifications, :as => [:member, :builder, :janitor, :gold, :platinum, :contributor, :admin, :moderator, :default]
   attr_accessible :is_locked, :is_sticky, :is_deleted, :as => [:admin, :moderator, :janitor]
   attr_readonly :topic_id
   belongs_to :creator, :class_name => "User"
@@ -15,6 +15,8 @@ class ForumPost < ActiveRecord::Base
   validate :validate_topic_is_unlocked
   before_destroy :validate_topic_is_unlocked
   after_save :delete_topic_if_original_post
+  after_save :update_email_notifications
+  attr_accessor :receive_email_notifications
 
   module SearchMethods
     def body_matches(body)
@@ -188,4 +190,22 @@ class ForumPost < ActiveRecord::Base
   def hidden_attributes
     super + [:text_index]
   end
+
+  def receive_email_notifications
+    @receive_email_notifications ||= ForumSubscription.where(:forum_topic_id => topic_id, :user_id => CurrentUser.user.id).exists?
+  end
+
+  def update_email_notifications
+    subscription = ForumSubscription.where(:forum_topic_id => topic_id, :user_id => CurrentUser.user.id).first
+
+    if receive_email_notifications == "1"
+      if subscription
+        subscription.update_attribute(:last_read_at, updated_at)
+      else
+        ForumSubscription.create(:forum_topic_id => topic_id, :user_id => CurrentUser.user.id, :last_read_at => updated_at)
+      end
+    else
+      subscription.destroy if subscription
+    end
+  end
 end

app/models/forum_subscription.rb

@@ -0,0 +1,22 @@
+class ForumSubscription < ActiveRecord::Base
+  belongs_to :user
+  belongs_to :forum_topic
+  attr_accessible :user, :forum_topic, :user_id, :forum_topic_id, :last_read_at, :delete_key
+
+  def self.prune!
+    where("last_read_at < ?", 3.months.ago).delete_all
+  end
+
+  def self.process_all!
+    ForumSubscription.find_each do |subscription|
+      forum_topic = subscription.forum_topic
+      if forum_topic.updated_at > subscription.last_read_at
+        CurrentUser.scoped(subscription.user, "127.0.0.1") do
+          forum_posts = forum_topic.posts.where("created_at >= ?", subscription.last_read_at).order("id desc")
+          UserMailer.forum_notice(subscription.user, forum_topic, forum_posts).deliver
+          subscription.update_attribute(:last_read_at, forum_topic.updated_at)
+        end
+      end
+    end
+  end
+end

app/models/forum_topic.rb

@@ -11,6 +11,7 @@ class ForumTopic < ActiveRecord::Base
   belongs_to :updater, :class_name => "User"
   has_many :posts, lambda {order("forum_posts.id asc")}, :class_name => "ForumPost", :foreign_key => "topic_id", :dependent => :destroy
   has_one :original_post, lambda {order("forum_posts.id asc")}, :class_name => "ForumPost", :foreign_key => "topic_id"
+  has_many :subscriptions, :class_name => "ForumSubscription"
   before_validation :initialize_creator, :on => :create
   before_validation :initialize_updater
   before_validation :initialize_is_deleted, :on => :create
@@ -99,6 +100,24 @@ class ForumTopic < ActiveRecord::Base
     end
   end
 
+  module SubscriptionMethods
+    def update_subscription!(user)
+      user_subscription = subscriptions.where(:user_id => user.id).first
+
+      if user_subscription
+        user_subscription.update_attribute(:last_read_at, updated_at)
+      else
+        subscriptions.create(:user_id => user.id, :last_read_at => updated_at, :delete_key => SecureRandom.urlsafe_base64(10))
+      end
+    end
+
+    def notify_subscriptions!
+      ForumSubscription.where(:forum_topic_id => id).where("last_read_at < ?", updated_at).find_each do |subscription|
+        
+      end
+    end
+  end
+
   extend SearchMethods
   include CategoryMethods
   include VisitMethods

app/views/forum_posts/partials/new/_form.html.erb

@@ -4,6 +4,8 @@
   <%= f.input :topic_id, :as => :hidden %>
   <%= dtext_field "forum_post", "body" %>
 
+  <%= f.input :receive_email_notifications, :as => :boolean %>
+
   <%= f.button :submit, "Submit" %>
   <%= dtext_preview_button "forum_post", "body" %>
 <% end %>

app/views/user_mailer/dmail_notice.html.erb

@@ -1,5 +1,8 @@
 <!doctype html>
 <html>
+<head>
+  <%= stylesheet_link_tag "application", :media => "screen" %>
+</head>
 <body>
 <p><%= h @dmail.from.name %> said:</p>
 

app/views/user_mailer/forum_notice.html.erb

@@ -0,0 +1,21 @@
+<!doctype html>
+<html>
+<head>
+  <%= stylesheet_link_tag "application", :media => "screen" %>
+</head>
+<body>
+<p><%= @forum_topic.title %> was updated:</p>
+
+<% @forum_posts.each do |forum_post| %>
+  <div class="prose">
+    <p class="author">
+      <%= forum_post.creator_name %> said:
+    </p>
+    <%= format_text(forum_post.body) %>
+  </div>
+<% end %>
+
+<p><%= link_to "View topic", forum_topic_path(@forum_topic, :page => @forum_topic.last_page, :host => Danbooru.config.hostname, :only_path => false) %></p>
+
+</body>
+</html>