4 files changed, 64 insertions, 10 deletions

diff --git a/app/views/admin/index.html.erb b/app/views/admin/index.html.erb
index 77b45f4..c67ccb3 100644
--- a/app/views/admin/index.html.erb
+++ b/app/views/admin/index.html.erb
@@ -82,9 +82,9 @@
 </div>
 
 <div id="current_drafts_table">
-  
-  <h2>Current Drafts (<%= @drafts_count %>)</h2>
-  
+
+  <h2>Current Drafts & Autosaves (<%= @drafts_count %>)</h2>
+
   <table class="node_table">
     <tr class="header">
       <th class="node_id">ID</th>
@@ -92,6 +92,7 @@
       <th class="actions">Actions</th>
       <th class="editor">Locked by</th>
       <th class="revision">Rev.</th>
+      <th class="autosave">Autosave</th>
     </tr>
     <% @drafts.each do |node| %>
     <tr class="<%= cycle("even", "odd") %>">
@@ -103,6 +104,9 @@
       <td class="actions">
         <%= link_to 'show',      node_path(node) %>
         <%= link_to 'Revisions', node_revisions_path(node) %>
+        <% if pair = node.available_layer_pairs.last %>
+          <%= link_to 'diff', diff_node_revisions_path(node, start_revision: pair.first, end_revision: pair.last) %>
+        <% end %>
       </td>
       <td>
         <%= node.lock_owner.login if node.lock_owner %>
@@ -110,6 +114,9 @@
       <td>
         <%= link_to ( node.draft ? node.draft.revision : (node.head ? node.head.revision : "EMPTY" ) ), node_revisions_path(node) %>
       </td>
+      <td class="autosave">
+        <%= node.autosave ? "unsaved changes" : "" %>
+      </td>
     </tr>
     <% end %>
   </table>
diff --git a/app/views/nodes/edit.html.erb b/app/views/nodes/edit.html.erb
index cdc9b36..1c19410 100644
--- a/app/views/nodes/edit.html.erb
+++ b/app/views/nodes/edit.html.erb
@@ -6,9 +6,16 @@
         disabled: @node.autosave.present? %>
 
   <% if @node.autosave || (@node.draft && @node.head) %>
-    <%= button_to (@node.draft && !@node.autosave ? 'Destroy Draft' : 'Discard changes'),
+    <%= button_to (@node.draft && !@node.autosave ? 'Destroy Draft' : 'Discard Autosave'),
           revert_node_path(@node), method: :put,
           form: { data: { confirm: "This cannot be undone. Continue?" }, class: 'button_to destructive' } %>
+    <% if pair = @node.available_layer_pairs.find { |p| p.include?(:autosave) } %>
+      <%= button_to 'What changed?',
+            diff_node_revisions_path(@node),
+            method: :get,
+            params: { start_revision: pair.first, end_revision: pair.last },
+            form: { class: 'button_to computation' } %>
+    <% end %>
   <% end %>
 
   <%= submit_tag "Save Draft", form: dom_id(@node, :edit) %>
diff --git a/app/views/nodes/show.html.erb b/app/views/nodes/show.html.erb
index 036caf2..2469310 100644
--- a/app/views/nodes/show.html.erb
+++ b/app/views/nodes/show.html.erb
@@ -32,6 +32,16 @@
           <% end %>
         </div>
 
+        <% @node.available_layer_pairs.each do |pair| %>
+          <div class="node_info_item">
+            <%= button_to "Diff #{pair.first.to_s.capitalize} vs. #{pair.last.to_s.capitalize}",
+                  diff_node_revisions_path(@node),
+                  method: :get,
+                  params: { start_revision: pair.first, end_revision: pair.last },
+                  form: { class: 'button_to computation' } %>
+          </div>
+        <% end %>
+
         <% unless locked_by_other %>
           <% if @node.draft && !@node.autosave %>
             <div class="node_info_item">
@@ -41,7 +51,7 @@
           <% end %>
           <% if @node.draft || @node.autosave %>
             <div class="node_info_item">
-              <%= button_to (@node.draft && !@node.autosave ? 'Destroy Draft' : 'Discard changes'),
+              <%= button_to (@node.draft && !@node.autosave ? 'Destroy Draft' : 'Discard Autosave'),
                     revert_node_path(@node), method: :put,
                     form: { data: { confirm: "This cannot be undone. Continue?" }, class: 'button_to destructive' } %>
             </div>
diff --git a/app/views/revisions/diff.html.erb b/app/views/revisions/diff.html.erb
index d7bb528..3157dca 100644
--- a/app/views/revisions/diff.html.erb
+++ b/app/views/revisions/diff.html.erb
@@ -4,11 +4,41 @@
   <%= link_to 'Revisions', node_revisions_path(@node) %>
 </p>
 
-<%= form_tag diff_node_revisions_path do %>
-  <%= select_tag :start_revision, options_for_select(@node.pages.map{|x| x.revision}, params[:start_revision].to_i) %>
-  <%= select_tag :end_revision, options_for_select(@node.pages.map{|x| x.revision}, params[:end_revision].to_i) %>
-  <%= select_tag :view, options_for_select([['Inline', 'inline'], ['Side by side', 'side_by_side']], @diff_view) %>
-  <%= submit_tag 'Diff' %>
+<p class="diff_comparison_label">
+  Comparing <strong><%= describe_page_reference(params[:start_revision]) %></strong>
+  against <strong><%= describe_page_reference(params[:end_revision]) %></strong>
+</p>
+
+<% numeric_comparison = params[:start_revision].to_s =~ /\A\d+\z/ && params[:end_revision].to_s =~ /\A\d+\z/ %>
+
+<% if numeric_comparison %>
+  <%= form_tag diff_node_revisions_path do %>
+    <%= select_tag :start_revision, options_for_select(@node.pages.map{|x| x.revision}, params[:start_revision].to_i) %>
+    <%= select_tag :end_revision, options_for_select(@node.pages.map{|x| x.revision}, params[:end_revision].to_i) %>
+    <%= select_tag :view, options_for_select([['Inline', 'inline'], ['Side by side', 'side_by_side']], @diff_view) %>
+    <%= submit_tag 'Diff' %>
+  <% end %>
+<% else %>
+  <p class="node_action_bar standalone_action_bar"><%= link_to 'Compare two numbered revisions instead', node_revisions_path(@node) %></p>
+<% end %>
+
+<% if @available_layer_pairs.present? %>
+  <p class="node_action_bar standalone_action_bar">
+    <% @available_layer_pairs.each do |pair| %>
+      <% next if [params[:start_revision].to_s, params[:end_revision].to_s].sort == pair.map(&:to_s).sort %>
+      <%= button_to "Diff #{pair.first.to_s.capitalize} vs. #{pair.last.to_s.capitalize}",
+            diff_node_revisions_path(@node),
+            method: :get,
+            params: { start_revision: pair.first, end_revision: pair.last, view: @diff_view },
+            form: { class: 'button_to computation' } %>
+    <% end %>
+
+    <% if !@locked_by_other && (@node.autosave || @node.draft) %>
+      <%= button_to (@node.draft && !@node.autosave ? 'Destroy Draft' : 'Discard Autosave'),
+            revert_node_path(@node), method: :put,
+            form: { data: { confirm: "This cannot be undone. Continue?" }, class: 'button_to destructive' } %>
+    <% end %>
+  </p>
 <% end %>
 
 <div id="diffview">