rubocop: fix various Rubocop warnings.

app/helpers/application_helper.rb

@@ -1,5 +1,3 @@
-require 'dtext'
-
 module ApplicationHelper
   def listing_type(*fields, member_check: true, types: [:revert, :standard])
     (fields.reduce(false) { |acc, field| acc || params.dig(:search, field).present? } && (!member_check || CurrentUser.is_member?) ? types[0] : types[1])
@@ -11,8 +9,7 @@ module ApplicationHelper
   end
 
   def diff_name_html(this_name, other_name)
-    pattern = Regexp.new('.')
-    DiffBuilder.new(this_name, other_name, pattern).build
+    DiffBuilder.new(this_name, other_name, /./).build
   end
 
   def diff_body_html(record, other, field)
@@ -21,7 +18,7 @@ module ApplicationHelper
       return h(diff_record[field]).gsub(/\r?\n/, '<span class="paragraph-mark">¶</span><br>').html_safe
     end
 
-    pattern = Regexp.new('(?:<.+?>)|(?:\w+)|(?:[ \t]+)|(?:\r?\n)|(?:.+?)')
+    pattern = /(?:<.+?>)|(?:\w+)|(?:[ \t]+)|(?:\r?\n)|(?:.+?)/
     DiffBuilder.new(record[field], other[field], pattern).build
   end
 
@@ -32,18 +29,17 @@ module ApplicationHelper
       return type == "previous" ? "New" : ""
     end
 
-    statuses = []
-    record.class.status_fields.each do |field, status|
-      if record.has_attribute?(field)
-        statuses += [status] if record[field] != other[field]
-      else
-        statuses += [status] if record.send(field, type)
-      end
+    changed_fields = record.class.status_fields.select do |field, status|
+      (record.has_attribute?(field) && record[field] != other[field]) ||
+      (!record.has_attribute?(field) && record.send(field, type))
     end
 
+    statuses = changed_fields.map { |field, status| status }
     altered = record.updater_id != other.updater_id
 
-    %(<div class="version-statuses" data-altered="#{altered}">#{statuses.join("<br>")}</div>).html_safe
+    tag.div(class: "version-statuses", "data-altered": altered) do
+      safe_join(statuses, tag.br)
+    end
   end
 
   def wordbreakify(string)

app/helpers/forum_topics_helper.rb

@@ -4,7 +4,7 @@ module ForumTopicsHelper
   end
 
   def available_min_user_levels
-    ForumTopic::MIN_LEVELS.select { |name, level| level <= CurrentUser.level }.to_a
+    ForumTopic::MIN_LEVELS.select { |_name, level| level <= CurrentUser.level }.to_a
   end
 
   def new_forum_topic?(topic, read_forum_topics)

app/helpers/popular_posts_helper.rb

@@ -22,11 +22,12 @@ module PopularPostsHelper
   end
 
   def date_range_description(date, scale, min_date, max_date)
-    if scale == "day"
+    case scale
+    when "day"
       date.strftime("%B %d, %Y")
-    elsif scale == "week"
+    when "week"
       "#{min_date.strftime("%B %d, %Y")} - #{max_date.strftime("%B %d, %Y")}"
-    elsif scale == "month"
+    when "month"
       date.strftime("%B %Y")
     end
   end

app/helpers/post_versions_helper.rb

@@ -40,12 +40,12 @@ module PostVersionsHelper
   def post_version_field(post_version, field)
     value = post_version_value(post_version.send(field))
     prefix = (field == :parent_id ? "parent" : field.to_s)
-    search = prefix + ":" + value.to_s
+    search = "#{prefix}:#{value}"
     display = (field == :rating ? post_version.pretty_rating : value)
     %(<b>#{field.to_s.titleize}:</b> #{link_to(display, posts_path(:tags => search))}).html_safe
   end
 
   def post_version_value(value)
-    return (value.present? ? value : "none")
+    value.presence || "none"
   end
 end

app/helpers/wiki_pages_helper.rb

@@ -1,6 +1,9 @@
 module WikiPagesHelper
   def wiki_page_other_names_list(wiki_page)
-    names_html = wiki_page.other_names.map {|name| link_to(name, "http://www.pixiv.net/search.php?s_mode=s_tag_full&word=#{u(name)}", :class => "wiki-other-name")}
-    names_html.join(" ").html_safe
+    names_html = wiki_page.other_names.map do |name|
+      link_to(name, "https://www.pixiv.net/tags/#{u(name)}/artworks", class: "wiki-other-name")
+    end
+
+    safe_join(names_html, " ")
   end
 end