canvas-lms/lib/mutable.rb

#
# Copyright (C) 2011 - present Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.

module Mutable

  attr_accessor :recently_unmuted

  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    def declare_mutable_broadcast_policy(options)
      policy       = options[:policy]
      participants = options[:participants]

      policy.dispatch :assignment_unmuted
      policy.to { participants }
      policy.whenever do |record|
        @recently_unmuted
      end
    end
  end

  def mute!
    return if muted?
    self.update_attribute(:muted, true)
    clear_sent_messages
    hide_submissions if respond_to?(:hide_submissions)
    ensure_post_policy(post_manually: true) if respond_to?(:ensure_post_policy)
    true
  end

  def unmute!
    return unless muted?
    self.update_attribute(:muted, false)
    broadcast_unmute_event
    post_submissions if respond_to?(:post_submissions)
    ensure_post_policy(post_manually: false) if respond_to?(:ensure_post_policy)
    true
  end

  def broadcast_unmute_event
    @recently_unmuted = true
    self.save!
    @recently_unmuted = false
  end

  protected
  def clear_sent_messages
    self.clear_broadcast_messages if self.respond_to? :clear_broadcast_messages
  end

  def hide_stream_items(submissions:)
    if submissions.present?
      submission_ids = submissions.pluck(:id)
      stream_items = StreamItem.select([:id, :context_type, :context_id]).
        where(asset_type: 'Submission', asset_id: submission_ids).
        preload(:context).to_a
      stream_item_contexts = stream_items.map { |si| [si.context_type, si.context_id] }
      user_ids = submissions.map(&:user_id).uniq # hide stream items for submission owners, not instructors
      # note: unfortunately this will hide items for an instructor if instructor (somehow) has a submission too

      Shard.partition_by_shard(user_ids) do |user_ids_subset|
        StreamItemInstance.where(:stream_item_id => stream_items, :user_id => user_ids_subset).
            update_all_with_invalidation(stream_item_contexts, :hidden => true)
      end

      # Teachers want to hide their submission comments if they mute
      # the assignment after leaving them.
      instructor_ids = self.context.instructors.pluck(:id)
      visible_comment_sub_ids =
        SubmissionComment.where(hidden: false, submission_id: submission_ids, author_id: instructor_ids).
          pluck(:submission_id)
      update_submission_comments_and_count(visible_comment_sub_ids, hidden: true, instructor_ids: instructor_ids) if visible_comment_sub_ids.any?
    end
  end

  def show_stream_items(submissions:)
    if submissions.present?
      submission_ids = submissions.pluck(:id)
      stream_items = StreamItem.select([:id, :context_type, :context_id]).
        where(asset_type: 'Submission', asset_id: submission_ids).
        preload(:context).to_a
      stream_item_contexts = stream_items.map { |si| [si.context_type, si.context_id] }
      associated_shards = stream_items.inject([]) { |result, si| result | si.associated_shards }
      Shard.with_each_shard(associated_shards) do
        StreamItemInstance.where(:hidden => true, :stream_item_id => stream_items).
            update_all_with_invalidation(stream_item_contexts, :hidden => false)
      end

      hidden_comment_sub_ids = SubmissionComment.where(hidden: true, submission_id: submission_ids).pluck(:submission_id)
      update_submission_comments_and_count(hidden_comment_sub_ids, hidden: false) if hidden_comment_sub_ids.any?
    end
  end

  def update_submission_comments_and_count(submission_ids, hidden: false, instructor_ids: nil)
    update_time = Time.zone.now
    submission_ids.each_slice(100) do |submission_id_slice|
      submission_comment_scope = SubmissionComment.where(hidden: !hidden, submission_id: submission_id_slice)
      submission_comment_scope = submission_comment_scope.where(author_id: instructor_ids) if instructor_ids.present?
      submission_comment_scope.update_all(hidden: hidden, updated_at: update_time)

      Submission.where(:id => submission_id_slice).
        update_all(["submission_comments_count = (SELECT COUNT(*) FROM #{SubmissionComment.quoted_table_name} WHERE
            submissions.id = submission_comments.submission_id AND submission_comments.hidden = ? AND
            submission_comments.draft IS NOT TRUE AND submission_comments.provisional_grade_id IS NULL)", false])
    end
  end

  private

  def update_muted_status!
    # With post policies active, an assignment is considered "muted" if it has any
    # unposted submissions.
    has_unposted_submissions = submissions.active.unposted.exists?
    update!(muted: has_unposted_submissions) if muted? != has_unposted_submissions
  end
end