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

app/models/announcement.rb

@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: announcements
+#
+#  id           :bigint(8)        not null, primary key
+#  text         :text             default(""), not null
+#  published    :boolean          default(FALSE), not null
+#  all_day      :boolean          default(FALSE), not null
+#  scheduled_at :datetime
+#  starts_at    :datetime
+#  ends_at      :datetime
+#  created_at   :datetime         not null
+#  updated_at   :datetime         not null
+#
+
+class Announcement < ApplicationRecord
+  after_commit :queue_publish, on: :create
+
+  scope :unpublished, -> { where(published: false) }
+  scope :published, -> { where(published: true) }
+  scope :without_muted, ->(account) { joins("LEFT OUTER JOIN announcement_mutes ON announcement_mutes.announcement_id = announcements.id AND announcement_mutes.account_id = #{account.id}").where('announcement_mutes.id IS NULL') }
+  scope :chronological, -> { order(Arel.sql('COALESCE(announcements.starts_at, announcements.scheduled_at, announcements.created_at) ASC')) }
+
+  has_many :announcement_mutes, dependent: :destroy
+  has_many :announcement_reactions, dependent: :destroy
+
+  validates :text, presence: true
+  validates :starts_at, presence: true, if: -> { ends_at.present? }
+  validates :ends_at, presence: true, if: -> { starts_at.present? }
+
+  before_validation :set_all_day
+  before_validation :set_starts_at, on: :create
+  before_validation :set_ends_at, on: :create
+
+  def time_range?
+    starts_at.present? && ends_at.present?
+  end
+
+  def mentions
+    @mentions ||= Account.from_text(text)
+  end
+
+  def tags
+    @tags ||= Tag.find_or_create_by_names(Extractor.extract_hashtags(text))
+  end
+
+  def emojis
+    @emojis ||= CustomEmoji.from_text(text)
+  end
+
+  def reactions(account = nil)
+    records = begin
+      scope = announcement_reactions.group(:announcement_id, :name, :custom_emoji_id).order(Arel.sql('MIN(created_at) ASC'))
+
+      if account.nil?
+        scope.select('name, custom_emoji_id, count(*) as count, false as me')
+      else
+        scope.select("name, custom_emoji_id, count(*) as count, exists(select 1 from announcement_reactions r where r.account_id = #{account.id} and r.announcement_id = announcement_reactions.announcement_id and r.name = announcement_reactions.name) as me")
+      end
+    end
+
+    ActiveRecord::Associations::Preloader.new.preload(records, :custom_emoji)
+    records
+  end
+
+  private
+
+  def set_all_day
+    self.all_day = false if starts_at.blank? || ends_at.blank?
+  end
+
+  def set_starts_at
+    self.starts_at = starts_at.change(hour: 0, min: 0, sec: 0) if all_day? && starts_at.present?
+  end
+
+  def set_ends_at
+    self.ends_at = ends_at.change(hour: 23, min: 59, sec: 59) if all_day? && ends_at.present?
+  end
+
+  def queue_publish
+    PublishScheduledAnnouncementWorker.perform_async(id) if scheduled_at.blank?
+  end
+end