FEATURE: set notification levels when added to a group (#10378)

* FEATURE: set notification levels when added to a group

This feature allows admins and group owners to define default
category and tag tracking levels that will be applied to user
preferences automatically at the time when users are added to the
group. Users are free to change those preferences afterwards.
When removed from a group, the user's notification preferences aren't
changed.

spec/models/group_user_spec.rb

@@ -32,4 +32,123 @@ describe GroupUser do
     expect(gu.notification_level).to eq(NotificationLevels.all[:regular])
   end
 
+  describe "default category notifications" do
+    let(:group) { Fabricate(:group) }
+    let(:user) { Fabricate(:user) }
+    let(:category1) { Fabricate(:category) }
+    let(:category2) { Fabricate(:category) }
+    let(:category3) { Fabricate(:category) }
+    let(:category4) { Fabricate(:category) }
+
+    def levels
+      CategoryUser.notification_levels
+    end
+
+    it "doesn't change anything with no configured defaults" do
+      expect { group.add(user) }.to_not change { CategoryUser.count }
+    end
+
+    it "adds new category notifications" do
+      group.muted_category_ids = [category1.id]
+      group.tracking_category_ids = [category2.id]
+      group.watching_category_ids = [category3.id]
+      group.watching_first_post_category_ids = [category4.id]
+      group.save!
+      expect { group.add(user) }.to change { CategoryUser.count }.by(4)
+      h = CategoryUser.notification_levels_for(Guardian.new(user))
+      expect(h[category1.id]).to eq(levels[:muted])
+      expect(h[category2.id]).to eq(levels[:tracking])
+      expect(h[category3.id]).to eq(levels[:watching])
+      expect(h[category4.id]).to eq(levels[:watching_first_post])
+    end
+
+    it "only upgrades notifications" do
+      CategoryUser.create!(user: user, category_id: category1.id, notification_level: levels[:muted])
+      CategoryUser.create!(user: user, category_id: category2.id, notification_level: levels[:tracking])
+      CategoryUser.create!(user: user, category_id: category3.id, notification_level: levels[:watching_first_post])
+      CategoryUser.create!(user: user, category_id: category4.id, notification_level: levels[:watching])
+      group.watching_first_post_category_ids = [category1.id, category2.id, category3.id, category4.id]
+      group.save!
+      group.add(user)
+      h = CategoryUser.notification_levels_for(Guardian.new(user))
+      expect(h[category1.id]).to eq(levels[:watching_first_post])
+      expect(h[category2.id]).to eq(levels[:watching_first_post])
+      expect(h[category3.id]).to eq(levels[:watching_first_post])
+      expect(h[category4.id]).to eq(levels[:watching])
+    end
+
+    it "merges notifications" do
+      CategoryUser.create!(user: user, category_id: category1.id, notification_level: CategoryUser.notification_levels[:tracking])
+      CategoryUser.create!(user: user, category_id: category2.id, notification_level: CategoryUser.notification_levels[:watching])
+      CategoryUser.create!(user: user, category_id: category4.id, notification_level: CategoryUser.notification_levels[:watching_first_post])
+      group.muted_category_ids = [category3.id]
+      group.tracking_category_ids = [category4.id]
+      group.save!
+      group.add(user)
+      h = CategoryUser.notification_levels_for(Guardian.new(user))
+      expect(h[category1.id]).to eq(levels[:tracking])
+      expect(h[category2.id]).to eq(levels[:watching])
+      expect(h[category3.id]).to eq(levels[:muted])
+      expect(h[category4.id]).to eq(levels[:watching_first_post])
+    end
+  end
+
+  describe "default tag notifications" do
+    let(:group) { Fabricate(:group) }
+    let(:user) { Fabricate(:user) }
+    let(:tag1) { Fabricate(:tag) }
+    let(:tag2) { Fabricate(:tag) }
+    let(:tag3) { Fabricate(:tag) }
+    let(:tag4) { Fabricate(:tag) }
+    let(:synonym1) { Fabricate(:tag, target_tag: tag1) }
+
+    def levels
+      TagUser.notification_levels
+    end
+
+    it "doesn't change anything with no configured defaults" do
+      expect { group.add(user) }.to_not change { TagUser.count }
+    end
+
+    it "adds new tag notifications" do
+      group.muted_tags = [synonym1.name]
+      group.tracking_tags = [tag2.name]
+      group.watching_tags = [tag3.name]
+      group.watching_first_post_tags = [tag4.name]
+      group.save!
+      expect { group.add(user) }.to change { TagUser.count }.by(4)
+      expect(TagUser.lookup(user, :muted).pluck(:tag_id)).to eq([tag1.id])
+      expect(TagUser.lookup(user, :tracking).pluck(:tag_id)).to eq([tag2.id])
+      expect(TagUser.lookup(user, :watching).pluck(:tag_id)).to eq([tag3.id])
+      expect(TagUser.lookup(user, :watching_first_post).pluck(:tag_id)).to eq([tag4.id])
+    end
+
+    it "only upgrades notifications" do
+      TagUser.create!(user: user, tag_id: tag1.id, notification_level: levels[:muted])
+      TagUser.create!(user: user, tag_id: tag2.id, notification_level: levels[:tracking])
+      TagUser.create!(user: user, tag_id: tag3.id, notification_level: levels[:watching_first_post])
+      TagUser.create!(user: user, tag_id: tag4.id, notification_level: levels[:watching])
+      group.watching_first_post_tags = [tag1.name, tag2.name, tag3.name, tag4.name]
+      group.save!
+      group.add(user)
+      expect(TagUser.lookup(user, :muted).pluck(:tag_id)).to be_empty
+      expect(TagUser.lookup(user, :tracking).pluck(:tag_id)).to be_empty
+      expect(TagUser.lookup(user, :watching).pluck(:tag_id)).to eq([tag4.id])
+      expect(TagUser.lookup(user, :watching_first_post).pluck(:tag_id)).to contain_exactly(tag1.id, tag2.id, tag3.id)
+    end
+
+    it "merges notifications" do
+      TagUser.create!(user: user, tag_id: tag1.id, notification_level: levels[:tracking])
+      TagUser.create!(user: user, tag_id: tag2.id, notification_level: levels[:watching])
+      TagUser.create!(user: user, tag_id: tag4.id, notification_level: levels[:watching_first_post])
+      group.muted_tags = [tag3.name]
+      group.tracking_tags = [tag2.name]
+      group.save!
+      group.add(user)
+      expect(TagUser.lookup(user, :muted).pluck(:tag_id)).to eq([tag3.id])
+      expect(TagUser.lookup(user, :tracking).pluck(:tag_id)).to eq([tag1.id])
+      expect(TagUser.lookup(user, :watching).pluck(:tag_id)).to eq([tag2.id])
+      expect(TagUser.lookup(user, :watching_first_post).pluck(:tag_id)).to eq([tag4.id])
+    end
+  end
 end