Drag todos between contexts

Closes #1020

app/helpers/todos_helper.rb

@@ -122,7 +122,7 @@ module TodosHelper
                 :title => 'Drag onto another action to make it depend on that action',
                 :class => 'grip') +
       image_tag('blank.png', :width => 16, :height => 16, :border => 0,
-                :title => "Drop an action to make it depend on this action", :class => 'successor_target')
+                :title => "Drop an action to make it depend on this action", :class => 'successor_target drop_target')
     end
   end
   

app/views/contexts/_context.rhtml

@@ -16,4 +16,5 @@
     </div>
     <%= render :partial => "todos/todo", :collection => @not_done, :locals => { :parent_container_type => "context" } %>
   </div><!-- [end:items] -->
+  <div id="c_<%=context.id%>_target" class="context_target drop_target"></div>
 </div><!-- [end:c<%= context.id %>] -->

app/views/todos/update.js.rjs

@@ -153,3 +153,5 @@ else
   page.show 'error_status'
   page.replace_html 'error_status', "#{error_messages_for('todo')}"
 end
+
+page << "enable_rich_interaction();"

public/javascripts/application.js

@@ -232,21 +232,46 @@ function enable_rich_interaction(){
   function drop_todo(evt, ui) {
     dragged_todo = ui.draggable[0].id.split('_')[2];
     dropped_todo = $(this).parents('.item-show').get(0).id.split('_')[2];
-    ui.draggable.hide();
+    ui.draggable.remove();
     $(this).block({message: null});
     $.post(relative_to_root('todos/add_predecessor'),
         {successor: dragged_todo, predecessor: dropped_todo},
         null, 'script');
   }
 
+  function drag_todo(){
+    $('.drop_target').show();
+    $(this).parents(".container").find(".context_target").hide();
+  }
+
   $('.item-show').draggable({handle: '.grip',
       revert: 'invalid',
-      start: function() {$('.successor_target').show();},
-      stop: function() {$('.successor_target').hide();}});
+      start: drag_todo,
+      stop: function() {$('.drop_target').hide();}});
 
   $('.successor_target').droppable({drop: drop_todo,
       tolerance: 'pointer',
       hoverClass: 'hover'});
+  
+  /* Drag & drop for changing contexts */
+  function drop_todo_on_context(evt, ui) {
+    target = $(this);
+    dragged_todo = ui.draggable[0].id.split('_')[2];
+    context_id = this.id.split('_')[1];
+    ui.draggable.remove();
+    target.block({message: null});
+    setTimeout(function() {target.show()}, 0);
+    $.post(relative_to_root('todos/update'),
+        {id: dragged_todo,
+         "todo[id]": dragged_todo,
+         "todo[context_id]": context_id},
+        function(){target.unblock(); target.hide();}, 'script');
+  }
+
+  $('.context_target').droppable({
+    drop: drop_todo_on_context,
+    tolerance: 'pointer',
+    hoverClass: 'hover'});
 
   /* Reset auto updater */
   field_touched = false;

public/stylesheets/standard.css

@@ -939,11 +939,14 @@ div.message {
     cursor: move;
 }
 
+.drop_target {
+  display:none;
+}
+
 .successor_target {
   background-image:url("../images/add_successor_off.png");
   background-repeat: no-repeat;
   background-position: center right;
-  display: none;
 }
 
 .successor_target.hover {
@@ -952,6 +955,15 @@ div.message {
   background-position: center right;
 }
 
+.context_target {
+  height: 15px;
+  margin: 4px;
+  border: thick dotted #CCC;
+}
+
+.context_target.hover {
+}
+
 /* Error message styles */
 .fieldWithErrors {
     padding: 2px;