fix(perspective): Update MailboxPerspective.canApplyToThreads

- Checks if the account ids of the threads that want to be applied are
  contained inside the perspectives account ids. E.g.:
  - I can move thread from account A to unified inbox or inbox A, but
    not to inbox B.
  - I can move threads from account A to a folder in account A but not a
    folder in account B
- Update data transferred in drag + other minor updates

internal_packages/account-sidebar/lib/sidebar-item.coffee

@@ -4,7 +4,8 @@ _ = require 'underscore'
  FocusedPerspectiveStore,
  SyncbackCategoryTask,
  DestroyCategoryTask,
- Actions} = require 'nylas-exports'
+ Actions,
+ Utils} = require 'nylas-exports'
 {OutlineViewItem} = require 'nylas-component-kit'
 
 
@@ -65,27 +66,24 @@ class SidebarItem
       selected: isItemSelected(perspective)
       collapsed: isItemCollapsed(id) ? true
       counterStyle: counterStyle
-      dataTransferType: 'nylas-thread-ids'
+      dataTransferType: 'nylas-threads-data'
       onDelete: if opts.deletable then onDeleteItem else undefined
       onEdited: if opts.editable then onEditItem else undefined
       onToggleCollapsed: toggleItemCollapsed
       onDrop: (item, event) ->
         jsonString = event.dataTransfer.getData(item.dataTransferType)
-        ids = null
-        try
-          ids = JSON.parse(jsonString);
-        catch err
-          console.error('OutlineViewItem onDrop: JSON parse #{err}');
-        return unless ids
-        item.perspective.applyToThreads(ids)
+        data = Utils.jsonParse(jsonString)
+        return unless data
+        item.perspective.applyToThreads(data.threadIds)
       shouldAcceptDrop: (item, event) ->
         target = item.perspective
         current = FocusedPerspectiveStore.current()
-
+        jsonString = event.dataTransfer.getData(item.dataTransferType)
+        data = Utils.jsonParse(jsonString)
+        return false unless data
         return false unless target
         return false if target.isEqual(current)
-        return false unless _.isEqual(target.accountIds, current.accountIds)
-        return false unless target.canApplyToThreads()
+        return false unless target.canApplyToThreads(data.accountIds)
 
         return item.dataTransferType in event.dataTransfer.types
 

internal_packages/thread-list/lib/thread-list.cjsx

@@ -106,17 +106,26 @@ class ThreadList extends React.Component
       event.preventDefault()
       return
 
-    if itemThreadId in ThreadListStore.dataSource().selection.ids()
-      dragThreadIds = ThreadListStore.dataSource().selection.ids()
+    dataSource = ThreadListStore.dataSource()
+    if itemThreadId in dataSource.selection.ids()
+      dragThreadIds = dataSource.selection.ids()
     else
       dragThreadIds = [itemThreadId]
 
+    dragAccountIds = dragThreadIds.map (threadId) -> dataSource.getById(threadId).accountId
+    dragAccountIds = _.uniq(dragAccountIds)
+
+    dragData = {
+      accountIds: dragAccountIds,
+      threadIds: dragThreadIds
+    }
+
     event.dataTransfer.effectAllowed = "move"
     event.dataTransfer.dragEffect = "move"
 
     canvas = CanvasUtils.canvasWithThreadDragImage(dragThreadIds.length)
     event.dataTransfer.setDragImage(canvas, 10, 10)
-    event.dataTransfer.setData('nylas-thread-ids', JSON.stringify(dragThreadIds))
+    event.dataTransfer.setData('nylas-threads-data', JSON.stringify(dragData))
     return
 
   _onDragEnd: (event) =>

src/flux/models/utils.coffee

@@ -496,3 +496,13 @@ Utils =
         fn.executing = true
         fn.apply(@, [fnFinished, fnReinvoked, arguments...])
     fnRun
+
+  # Parse json without throwing an error. Logs a sensible message to indicate
+  # the error occurred while parsing
+  jsonParse: (jsonString) =>
+    data = null
+    try
+      data = JSON.parse(jsonString)
+    catch err
+      console.error("JSON parse error: #{err}")
+    return data

src/mailbox-perspective.coffee

@@ -73,8 +73,9 @@ class MailboxPerspective
   threadUnreadCount: =>
     0
 
-  canApplyToThreads: =>
-    throw new Error("canApplyToThreads: Not implemented in base class.")
+  canApplyToThreads: (targetAccountIds) =>
+    targetIdsInCurrent = _.difference(targetAccountIds, @accountIds).length is 0
+    return targetIdsInCurrent
 
   applyToThreads: (threadsOrIds) =>
     throw new Error("applyToThreads: Not implemented in base class.")
@@ -149,7 +150,7 @@ class StarredMailboxPerspective extends MailboxPerspective
     return new MutableQuerySubscription(query, {asResultSet: true})
 
   canApplyToThreads: =>
-    true
+    super
 
   applyToThreads: (threadsOrIds) =>
     ChangeStarredTask = require './flux/tasks/change-starred-task'
@@ -224,7 +225,7 @@ class CategoryMailboxPerspective extends MailboxPerspective
     @_categories[0].name is 'inbox'
 
   canApplyToThreads: =>
-    not _.any @_categories, (c) -> c.isLockedCategory()
+    super and not _.any @_categories, (c) -> c.isLockedCategory()
 
   canArchiveThreads: =>
     for cat in @_categories