wikis: add "tag history", "wiki history", "what links here" sidebar options.

app/models/wiki_page.rb

@@ -76,6 +76,10 @@ class WikiPage < ApplicationRecord
         q = q.tag_matches(params[:tag])
       end
 
+      if params[:linked_to].present?
+        q = q.where(id: DtextLink.wiki_link.where(link_target: params[:linked_to]).select(:model_id))
+      end
+
       if params[:hide_deleted].to_s.truthy?
         q = q.where("is_deleted = false")
       end
@@ -165,6 +169,10 @@ class WikiPage < ApplicationRecord
     title.starts_with?(*META_WIKIS)
   end
 
+  def is_meta_wiki?
+    WikiPage.is_meta_wiki?(title)
+  end
+
   def wiki_page_changed?
     saved_change_to_title? || saved_change_to_body? || saved_change_to_is_locked? || saved_change_to_is_deleted? || saved_change_to_other_names?
   end

app/views/wiki_pages/_sidebar.html.erb

@@ -1,4 +1,16 @@
 <% content_for(:sidebar) do %>
   <%= render "posts/partials/index/blacklist" %>
   <%= render "wiki_pages/recent_changes" %>
+
+  <% if @wiki_page.present? %>
+    <h4>Options</h4>
+
+    <ul class="list-bulleted">
+      <% unless @wiki_page.is_meta_wiki? %>
+        <li><%= link_to "Tag History", post_versions_path(search: { changed_tags: @wiki_page.title }) %></li>
+      <% end %>
+      <li><%= link_to "Wiki History", wiki_page_versions_path(search: { wiki_page_id: @wiki_page.id }) %></li>
+      <li><%= link_to "What Links Here", wiki_pages_path(search: { linked_to: @wiki_page.title }) %></li>
+    </ul>
+  <% end %>
 <% end %>