add tag subscriptions

app/models/tag_subscription.rb

@@ -0,0 +1,81 @@
+class TagSubscription < ActiveRecord::Base
+  belongs_to :owner, :class_name => "User"
+  before_create :initialize_post_ids
+  before_save :normalize_name
+  before_save :limit_tag_count
+  scope :visible, :conditions => "is_visible_on_profile = TRUE"
+  attr_accessible :name, :tag_query, :post_ids, :is_visible_on_profile
+
+  def normalize_name
+    self.name = name.gsub(/\W/, "_")
+  end
+
+  def initialize_post_ids
+    process
+  end
+
+  def tag_query_array
+    Tag.scan_query(tag_query)
+  end
+
+  def limit_tag_count
+    self.tag_query = tag_query_array.slice(0, 20).join(" ")
+  end
+
+  def process
+    post_ids = tag_query_array.inject([]) do |all, tag|
+      all += Post.find_by_tags(tag, :limit => Danbooru.config.tag_subscription_post_limit / 3, :select => "posts.id", :order => "posts.id desc").map(&:id)
+    end
+    self.post_ids = post_ids.sort.reverse.slice(0, Danbooru.config.tag_subscription_post_limit).join(",")
+  end
+
+  def self.find_tags(subscription_name)
+    if subscription_name =~ /^(.+?):(.+)$/
+      user_name = $1
+      sub_group = $2
+    else
+      user_name = subscription_name
+      sub_group = nil
+    end
+
+    user = User.find_by_name(user_name)
+    if user
+      relation = where(["owner_id = ?", user.id])
+      
+      if sub_group
+        relation = relation.where(["name ILIKE ? ESCAPE E'\\\\'", sub_group.to_escaped_for_sql_like])
+      end
+
+      relation.map {|x| x.tag_query.split(/ /)}.flatten
+    else
+      []
+    end        
+  end
+
+  def self.find_post_ids(user_id, name = nil, limit = Danbooru.config.tag_subscription_post_limit)
+    relation = where(["owner_id = ?", user_id])
+    
+    if name
+      relation = relation.where(["name ILIKE ? ESCAPE E'\\\\'", name.to_escaped_for_sql_like])
+    end
+
+    relation.map {|x| x.post_ids.split(/,/)}.flatten.uniq.map(&:to_i).sort.reverse.slice(0, limit)
+  end
+
+  def self.find_posts(user_id, name = nil, limit = Danbooru.config.tag_subscription_post_limit)
+    Post.where(["id in (?)", find_post_ids(user_id, name, limit)]).all(:order => "id DESC", :limit => limit)
+  end
+
+  def self.process_all
+    all.each do |tag_subscription|
+      if $job_task_daemon_active != false && tag_subscription.owner.is_privileged?
+        begin
+          tag_subscription.process
+          tag_subscription.save
+        rescue Exception => x
+          raise if Rails.environment != "production"
+        end
+      end
+    end
+  end
+end