Add "Unassign All" button to user's assigned topics view

app/controllers/discourse_assign/assign_controller.rb

@@ -70,5 +70,11 @@ module DiscourseAssign
 
       render json: success_json
     end
+
+    def unassign_all
+      user = User.find_by(id: params[:user_id])
+      TopicAssigner.unassign_all(user, current_user)
+      render json: success_json
+    end
   end
 end

assets/javascripts/discourse-assign/controllers/user-activity-assigned.js.es6

@@ -0,0 +1,28 @@
+import { ajax } from 'discourse/lib/ajax';
+import computed from 'ember-addons/ember-computed-decorators';
+
+export default Ember.Controller.extend({
+  user: Ember.inject.controller(),
+
+  @computed('model.topics')
+  canUnassignAll(topics) {
+    return topics && topics.length && this.currentUser.get('staff');
+  },
+
+  actions: {
+    unassignAll() {
+      let user = this.get('user.model');
+      bootbox.confirm(
+        I18n.t("discourse_assign.unassign_all.confirm", { username: user.get('username') }),
+        value => {
+          if (value) {
+            ajax("/assign/unassign-all", {
+              type: 'PUT',
+              data: { user_id: user.get('id') }
+            }).then(() => this.send('unassignedAll'));
+          }
+        }
+      );
+    }
+  }
+});

assets/javascripts/discourse-assign/routes/user-activity-assigned.js.es6

@@ -3,7 +3,30 @@ import UserTopicListRoute from "discourse/routes/user-topic-list";
 export default UserTopicListRoute.extend({
   userActionType: 16,
   noContentHelpKey: "discourse_assigns.no_assigns",
-  model: function() {
-    return this.store.findFiltered('topicList', {filter: 'latest', params: {assigned:  this.modelFor('user').get('username_lower') }});
+
+  model() {
+    return this.store.findFiltered(
+      'topicList',
+      {
+        filter: 'latest',
+        params: { assigned: this.modelFor('user').get('username_lower') }
+      }
+    );
+  },
+
+  renderTemplate() {
+    this.render('user-activity-assigned');
+    this.render('user-topics-list', { into: 'user-activity-assigned' });
+  },
+
+  setupController(controller, model) {
+    this._super(controller, model);
+    controller.set('model', model);
+  },
+
+  actions: {
+    unassignedAll() {
+      this.refresh();
+    }
   }
 });

assets/javascripts/discourse/templates/user-activity-assigned.hbs

@@ -0,0 +1,11 @@
+{{#if canUnassignAll}}
+  <div class='assign-controls'>
+    {{d-button
+      action=(action "unassignAll")
+      icon="times"
+      label="discourse_assign.unassign_all.title"
+      class="btn-danger"}}
+  </div>
+{{/if}}
+
+{{outlet}}

assets/stylesheets/assigns.scss

@@ -1,3 +1,11 @@
+.user-right {
+  .assign-controls {
+    display: flex;
+    justify-content: flex-end;
+    margin-bottom: 0.5em;
+  }
+}
+
 .assigned-to {
   .d-icon, i.fa {
     margin-right: 0.5em;

config/locales/client.en.yml

@@ -9,6 +9,10 @@ en:
       assigned: "Assigned"
       assigned_to: "Assigned to"
       assign_notification: "<i title='assigned' class='fa fa-user-plus'></i><p><span>{{username}}</span> {{description}}</p>"
+      unassign_all:
+        title: "Unassign All Topics"
+        confirm: "Are you sure you want to unassign all topics from {{username}}?"
+
       unassign:
         title: "Unassign"
         help: "Unassign Topic"

config/routes.rb

@@ -2,5 +2,6 @@ DiscourseAssign::Engine.routes.draw do
   put "/claim/:topic_id" => "assign#claim"
   put "/assign" => "assign#assign"
   put "/unassign" => "assign#unassign"
+  put "/unassign-all" => "assign#unassign_all"
   get "/suggestions" => "assign#suggestions"
 end

jobs/unassign_bulk.rb

@@ -0,0 +1,10 @@
+module Jobs
+  class UnassignBulk < Jobs::Base
+    def execute(args)
+      assigned_by = User.find(args[:assigned_by_id])
+      Topic.where(id: args[:topic_ids]).each do |t|
+        TopicAssigner.new(t, assigned_by).unassign
+      end
+    end
+  end
+end

lib/topic_assigner.rb

@@ -1,6 +1,25 @@
 require_dependency 'email/sender'
 
 class ::TopicAssigner
+
+  def self.unassign_all(user, assigned_by)
+    topic_ids = TopicCustomField.where(name: 'assigned_to_id', value: user.id).pluck(:topic_id)
+
+    # Fast path: by doing this we can instantly refresh for the user showing no assigned topics
+    # while doing the "full" removal asynchronously.
+    TopicCustomField.where(
+      name: ['assigned_to_id', 'assigned_by_id'],
+      topic_id: topic_ids
+    ).delete_all
+
+    Jobs.enqueue(
+      :unassign_bulk,
+      user_id: user.id,
+      assigned_by_id: assigned_by.id,
+      topic_ids: topic_ids
+    )
+  end
+
   def self.backfill_auto_assign
     staff_mention = User.where('moderator OR admin')
       .pluck('username')
@@ -95,9 +114,7 @@ SQL
   end
 
   def assign(assign_to, silent: false)
-    @topic.custom_fields["assigned_to_id"] = assign_to.id
-    @topic.custom_fields["assigned_by_id"] = @assigned_by.id
-    @topic.save!
+    @topic.upsert_custom_fields(assigned_to_id: assign_to.id, assigned_by_id: @assigned_by.id)
 
     first_post = @topic.posts.find_by(post_number: 1)
     first_post.publish_change_to_clients!(:revised, reload_topic: true)
@@ -162,9 +179,7 @@ SQL
 
   def unassign(silent: false)
     if assigned_to_id = @topic.custom_fields["assigned_to_id"]
-      @topic.custom_fields["assigned_to_id"] = nil
-      @topic.custom_fields["assigned_by_id"] = nil
-      @topic.save!
+      @topic.upsert_custom_fields(assigned_to_id: nil, assigned_by_id: nil)
 
       post = @topic.posts.where(post_number: 1).first
       return unless post.present?

plugin.rb

@@ -15,6 +15,7 @@ Discourse::Application.routes.append do
 end
 
 after_initialize do
+  require File.expand_path('../jobs/unassign_bulk', __FILE__)
   require 'topic_assigner'
 
   # Raise an invalid access error if a user tries to act on something

spec/lib/topic_assigner_spec.rb

@@ -22,4 +22,25 @@ RSpec.describe TopicAssigner do
       assert_publish_topic_state(pm, user) { assigner.unassign }
     end
   end
+
+  context "assigning and unassigning" do
+    let(:post) { Fabricate(:post) }
+    let(:topic) { post.topic }
+    let(:moderator) { Fabricate(:moderator) }
+    let(:assigner) { TopicAssigner.new(topic, moderator) }
+
+    it "can assign and unassign correctly" do
+      assigner.assign(moderator)
+      expect(TopicQuery.new(moderator, assigned: moderator.username).list_latest.topics).to be_present
+      assigner.unassign
+      expect(TopicQuery.new(moderator, assigned: moderator.username).list_latest.topics).to be_blank
+    end
+
+    it "can unassign all a user's topics at once" do
+      assigner.assign(moderator)
+      TopicAssigner.unassign_all(moderator, moderator)
+      expect(TopicQuery.new(moderator, assigned: moderator.username).list_latest.topics).to be_blank
+    end
+
+  end
 end