FEATURE: initial implemenation of anonymous posting mode

app/services/anonymous_shadow_creator.rb

@@ -0,0 +1,59 @@
+class AnonymousShadowCreator
+
+  def self.get_master(user)
+    return unless user
+    return if !SiteSetting.allow_anonymous_posting
+
+    if (master_id = user.custom_fields["master_id"].to_i) > 0
+      User.find_by(id: master_id)
+    end
+
+  end
+
+  def self.get(user)
+    return unless user
+    return if !SiteSetting.allow_anonymous_posting ||
+       user.trust_level < SiteSetting.anonymous_posting_min_trust_level
+
+    if (shadow_id = user.custom_fields["shadow_id"].to_i) > 0
+      User.find_by(id: shadow_id) || create_shadow(user)
+    else
+      create_shadow(user)
+    end
+  end
+
+  def self.create_shadow(user)
+    User.transaction do
+      shadow = User.create!(
+        password: SecureRandom.hex,
+        email: "#{SecureRandom.hex}@#{SecureRandom.hex}.com",
+        name: "",
+        username: UserNameSuggester.suggest(I18n.t(:anonymous).downcase),
+        active: true,
+        trust_level: 1,
+        trust_level_locked: true,
+        email_private_messages: false,
+        email_digests: false,
+        created_at: user.created_at
+      )
+
+      shadow.email_tokens.update_all  confirmed: true
+      shadow.activate
+
+
+      UserCustomField.create!(user_id: user.id,
+                              name: "shadow_id",
+                              value: shadow.id)
+
+      UserCustomField.create!(user_id: shadow.id,
+                              name: "master_id",
+                              value: user.id)
+
+      shadow.reload
+      user.reload
+
+      shadow
+
+    end
+  end
+end