screenreaders announce item count after search

fixes CNVS-21510

test plan:
  - with screenreader on
  - go to quizzes index
    - filter by title in the
      search box
    - the screenreader announces
      the new item count
  - go to assignment index
    - do the same

Change-Id: I172e84cbf9fd3f0de49f6faf76d7336eb622d2c8
Reviewed-on: https://gerrit.instructure.com/69858
Tested-by: Jenkins
Reviewed-by: Matt Berns <mberns@instructure.com>
QA-Review: Deepeeca Soundarrajan <dsoundarrajan@instructure.com>
Product-Review: Aaron Cannon <acannon@instructure.com>

app/coffeescripts/views/assignments/AssignmentGroupListItemView.coffee

@@ -207,17 +207,19 @@ define [
 
     search: (regex, gradingPeriod) ->
       @resetBorders()
+      assignmentCount = @collection.reduce( (count, as) =>
+        count++ if as.search(regex, gradingPeriod)
+        count
+      , 0)
 
-      atleastone = false
-      @collection.each (as) =>
-        atleastone = true if as.search(regex, gradingPeriod)
+      atleastone = assignmentCount > 0
       if atleastone
         @show()
         @expand(false)
         @borderFix()
       else
         @hide()
-      atleastone
+      assignmentCount
 
     endSearch: ->
       @resetBorders()

app/coffeescripts/views/assignments/IndexView.coffee

@@ -9,6 +9,7 @@ define [
   'jst/assignments/NoAssignmentsSearch'
   'compiled/views/assignments/AssignmentKeyBindingsMixin'
   'compiled/userSettings'
+  'compiled/jquery.rails_flash_notifications'
 ], (I18n, KeyboardNavDialog, keyboardNavTemplate, $, _, Backbone, template, NoAssignments, AssignmentKeyBindingsMixin, userSettings) ->
 
   class IndexView extends Backbone.View
@@ -90,9 +91,13 @@ define [
       else
         regex = new RegExp(@cleanSearchTerm(term), 'ig')
         #search
-        atleastoneGroup = false
-        @collection.each (group) =>
-          atleastoneGroup = true if group.groupView.search(regex, gradingPeriod)
+        matchingAssignmentCount = @collection.reduce( (runningTotal, group) ->
+          additionalCount = group.groupView.search(regex, gradingPeriod)
+          runningTotal + additionalCount
+        , 0)
+
+        atleastoneGroup = matchingAssignmentCount > 0
+        @alertForMatchingGroups(matchingAssignmentCount)
 
         #add noAssignments placeholder
         if !atleastoneGroup
@@ -109,6 +114,15 @@ define [
             @noAssignments.remove()
             @noAssignments = null
 
+    alertForMatchingGroups: (numAssignments) ->
+      msg = I18n.t({
+          one: "1 assignment found."
+          other: "%{count} assignments found."
+          zero: "No matching assignments found."
+        }, count: numAssignments
+      )
+      $.screenReaderFlashMessageExclusive(msg)
+
     cleanSearchTerm: (text) ->
       text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&")
 

app/coffeescripts/views/quizzes/IndexView.coffee

@@ -1,10 +1,12 @@
 define [
+  'i18n!quizzes'
   'jquery'
   'underscore'
   'Backbone'
   'compiled/views/quizzes/QuizItemGroupView'
   'jst/quizzes/IndexView'
-], ($, _, Backbone, QuizItemGroupView, template) ->
+  'compiled/jquery.rails_flash_notifications'
+], (I18n, $, _, Backbone, QuizItemGroupView, template) ->
 
   class IndexView extends Backbone.View
     template: template
@@ -37,8 +39,27 @@ define [
 
     keyUpSearch: _.debounce ->
       @filterResults()
+      @announceCount()
     , 200
 
     filterResults: =>
       _.each @views(), (view) =>
         view.filterResults($('#searchTerm').val())
+
+    announceCount: =>
+      searchTerm = $('#searchTerm').val()
+      return if searchTerm == '' || searchTerm == null
+
+      matchingQuizCount = _.reduce(@views(), (runningCount, view) =>
+        return runningCount + view.matchingCount(searchTerm)
+      , 0)
+      @announceMatchingQuizzes(matchingQuizCount)
+
+    announceMatchingQuizzes: (numQuizzes) ->
+      msg = I18n.t({
+          one: "1 quiz found."
+          other: "%{count} quizzes found."
+          zero: "No matching quizzes found."
+        }, count: numQuizzes
+      )
+      $.screenReaderFlashMessageExclusive(msg)

app/coffeescripts/views/quizzes/QuizItemGroupView.coffee

@@ -32,9 +32,13 @@ define [
         if !!model.get('hidden') != hidden
           anyChanged = true
           model.set('hidden', hidden)
-
       @render() if anyChanged
 
+    matchingCount: (term) =>
+      _.select( @collection.models, (m) =>
+        @filter(m, term)
+      ).length
+
     filter: (model, term) =>
       return true unless term