Add announcements (#12662)

* Add announcements

Fix #11006

* Add reactions to announcements

* Add admin UI for announcements

* Add unit tests

* Fix issues

- Add `with_dismissed` param to announcements API
- Fix end date not being formatted when time range is given
- Fix announcement delete causing reactions to send streaming updates
- Fix announcements container growing too wide and mascot too small
- Fix `all_day` being settable when no time range is given
- Change text "Update" to "Announcement"

* Fix scheduler unpublishing announcements before they are due

* Fix filter params not being passed to announcements filter

1 files changed, 39 insertions, 0 deletions

diff --git a/app/models/announcement_filter.rb b/app/models/announcement_filter.rb
new file mode 100644
index 000000000..950852460
--- /dev/null
+++ b/app/models/announcement_filter.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class AnnouncementFilter
+  KEYS = %i(
+    published
+    unpublished
+  ).freeze
+
+  attr_reader :params
+
+  def initialize(params)
+    @params = params
+  end
+
+  def results
+    scope = Announcement.unscoped
+
+    params.each do |key, value|
+      next if key.to_s == 'page'
+
+      scope.merge!(scope_for(key, value.to_s.strip)) if value.present?
+    end
+
+    scope.chronological
+  end
+
+  private
+
+  def scope_for(key, _value)
+    case key.to_s
+    when 'published'
+      Announcement.published
+    when 'unpublished'
+      Announcement.unpublished
+    else
+      raise "Unknown filter: #{key}"
+    end
+  end
+end