1 files changed, 84 insertions, 0 deletions
diff --git a/app/assets/javascripts/LabelManager.js.coffee b/app/assets/javascripts/LabelManager.js.coffee
new file mode 100644
index 00000000000..365a062bb81
--- /dev/null
+++ b/app/assets/javascripts/LabelManager.js.coffee
@@ -0,0 +1,84 @@
+class @LabelManager
+  errorMessage: 'Unable to update label prioritization at this time'
+
+  constructor: (opts = {}) ->
+    # Defaults
+    {
+      @togglePriorityButton = $('.js-toggle-priority')
+      @prioritizedLabels = $('.js-prioritized-labels')
+      @otherLabels = $('.js-other-labels')
+    } = opts
+
+    @prioritizedLabels.sortable(
+      items: 'li'
+      placeholder: 'list-placeholder'
+      axis: 'y'
+      update: @onPrioritySortUpdate.bind(@)
+    )
+
+    @bindEvents()
+
+  bindEvents: ->
+    @togglePriorityButton.on 'click', @, @onTogglePriorityClick
+
+  onTogglePriorityClick: (e) ->
+    e.preventDefault()
+    _this = e.data
+    $btn = $(e.currentTarget)
+    $label = $("##{$btn.data('domId')}")
+    action = if $btn.parents('.js-prioritized-labels').length then 'remove' else 'add'
+    _this.toggleLabelPriority($label, action)
+
+  toggleLabelPriority: ($label, action, persistState = true) ->
+    _this = @
+    url = $label.find('.js-toggle-priority').data 'url'
+
+    $target = @prioritizedLabels
+    $from = @otherLabels
+
+    # Optimistic update
+    if action is 'remove'
+      $target = @otherLabels
+      $from = @prioritizedLabels
+
+    if $from.find('li').length is 1
+      $from.find('.empty-message').show()
+
+    if not $target.find('li').length
+      $target.find('.empty-message').hide()
+
+    $label.detach().appendTo($target)
+
+    # Return if we are not persisting state
+    return unless persistState
+
+    if action is 'remove'
+      xhr = $.ajax url: url, type: 'DELETE'
+    else
+      xhr = @savePrioritySort($label, action)
+
+    xhr.fail @rollbackLabelPosition.bind(@, $label, action)
+
+  onPrioritySortUpdate: ->
+    xhr = @savePrioritySort()
+
+    xhr.fail ->
+      new Flash(@errorMessage, 'alert')
+
+  savePrioritySort: () ->
+    $.post
+      url: @prioritizedLabels.data('url')
+      data:
+        label_ids: @getSortedLabelsIds()
+
+  rollbackLabelPosition: ($label, originalAction)->
+    action = if originalAction is 'remove' then 'add' else 'remove'
+    @toggleLabelPriority($label, action, false)
+
+    new Flash(@errorMessage, 'alert')
+
+  getSortedLabelsIds: ->
+    sortedIds = []
+    @prioritizedLabels.find('li').each ->
+      sortedIds.push $(@).data 'id'
+    sortedIds