REFACTOR: Add full_url and display_name to User

Lets stop writing the same code over and over again.

app/controllers/list_controller.rb

@@ -245,8 +245,8 @@ class ListController < ApplicationController
     ensure_can_see_profile!(target_user)
 
     @title = "#{SiteSetting.title} - #{I18n.t("rss_description.user_topics", username: target_user.username)}"
-    @link = "#{Discourse.base_url}/u/#{target_user.username}/activity/topics"
-    @atom_link = "#{Discourse.base_url}/u/#{target_user.username}/activity/topics.rss"
+    @link = "#{target_user.full_url}/activity/topics"
+    @atom_link = "#{target_user.full_url}/activity/topics.rss"
     @description = I18n.t("rss_description.user_topics", username: target_user.username)
 
     @topic_list = TopicQuery

app/controllers/posts_controller.rb

@@ -132,7 +132,7 @@ class PostsController < ApplicationController
       format.rss do
         @posts = posts
         @title = "#{SiteSetting.title} - #{I18n.t("rss_description.user_posts", username: user.username)}"
-        @link = "#{Discourse.base_url}/u/#{user.username}/activity"
+        @link = "#{user.full_url}/activity"
         @description = I18n.t("rss_description.user_posts", username: user.username)
         render 'posts/latest', formats: [:rss]
       end

app/helpers/application_helper.rb

@@ -658,13 +658,7 @@ module ApplicationHelper
   end
 
   def rss_creator(user)
-    if user
-      if SiteSetting.prioritize_username_in_ux
-        "#{user.username}"
-      else
-        "#{user.name.presence || user.username }"
-      end
-    end
+    user&.display_name
   end
 
   def authentication_data

app/mailers/group_smtp_mailer.rb

@@ -83,18 +83,10 @@ class GroupSmtpMailer < ActionMailer::Base
     post.topic.allowed_users.each do |u|
       next if u.id == recipient_user.id
 
-      if SiteSetting.prioritize_username_in_ux?
       if u.staged?
         list.push("#{u.email}")
       else
-          list.push("[#{u.username}](#{Discourse.base_url}/u/#{u.username_lower})")
-        end
-      else
-        if u.staged?
-          list.push("#{u.email}")
-        else
-          list.push("[#{u.name.blank? ? u.username : u.name}](#{Discourse.base_url}/u/#{u.username_lower})")
-        end
+        list.push("[#{u.display_name}](#{u.full_url})")
       end
     end
 

app/mailers/user_notifications.rb

@@ -561,12 +561,7 @@ class UserNotifications < ActionMailer::Base
 
       post.topic.allowed_users.each do |u|
         next if u.id == user.id
-
-        if SiteSetting.prioritize_username_in_ux?
-          participant_list.push "[#{u.username}](#{Discourse.base_url}/u/#{u.username_lower})"
-        else
-          participant_list.push "[#{u.name.blank? ? u.username : u.name}](#{Discourse.base_url}/u/#{u.username_lower})"
-        end
+        participant_list.push "[#{u.display_name}](#{u.full_url})"
       end
 
       participants += participant_list.join(", ")

app/models/topic_poster.rb

@@ -16,12 +16,6 @@ class TopicPoster < OpenStruct
   end
 
   def name_and_description
-    if SiteSetting.prioritize_username_in_ux? || user.name.blank?
-      name = user.username
-    else
-      name = user.name
-    end
-
-    I18n.t("js.user.avatar.name_and_description", name: name, description: description)
+    I18n.t("js.user.avatar.name_and_description", name: user.display_name, description: description)
   end
 end

app/models/user.rb

@@ -1461,6 +1461,18 @@ class User < ActiveRecord::Base
     username_lower == User.normalize_username(another_username)
   end
 
+  def full_url
+    "#{Discourse.base_url}/u/#{encoded_username}"
+  end
+
+  def display_name
+    if SiteSetting.prioritize_username_in_ux?
+      username
+    else
+      name.presence || username
+    end
+  end
+
   protected
 
   def badge_grant

lib/system_message.rb

@@ -62,7 +62,7 @@ class SystemMessage
     {
       site_name: SiteSetting.title,
       username: @recipient.username,
-      user_preferences_url: "#{Discourse.base_url}/u/#{@recipient.username_lower}/preferences",
+      user_preferences_url: "#{@recipient.full_url}/preferences",
       new_user_tips: I18n.with_locale(@recipient.effective_locale) { I18n.t('system_messages.usage_tips.text_body_template', base_url: Discourse.base_url) },
       site_password: "",
       base_url: Discourse.base_url,