Support slash commands in noteable description and notes

Some important things to note:

- commands are removed from noteable.description / note.note
- commands are translated to params so that they are treated as normal
  params in noteable Creation services
- the logic is not in the models but in the Creation services, which is
  the right place for advanced logic that has nothing to do with what
  models should be responsible of!
- UI/JS needs to be updated to handle notes which consist of commands
  only
- the `/merge` command is not handled yet

Other improvements:

- Don't process commands in commit notes and display a flash is note is only commands
- Add autocomplete for slash commands
- Add description and params to slash command DSL methods
- Ensure replying by email with a commands-only note works
- Use :subscription_event instead of calling noteable.subscribe
- Support :todo_event in IssuableBaseService

Signed-off-by: Rémy Coutable <remy@rymai.me>

4 files changed, 245 insertions, 8 deletions

diff --git a/spec/services/issues/create_service_spec.rb b/spec/services/issues/create_service_spec.rb
index 1ee9f3aae4d..fcc3c0a00bd 100644
--- a/spec/services/issues/create_service_spec.rb
+++ b/spec/services/issues/create_service_spec.rb
@@ -73,5 +73,7 @@ describe Issues::CreateService, services: true do
         end
       end
     end
+
+    it_behaves_like 'new issuable record that supports slash commands'
   end
 end
diff --git a/spec/services/merge_requests/create_service_spec.rb b/spec/services/merge_requests/create_service_spec.rb
index b84a580967a..c1e4f8bd96b 100644
--- a/spec/services/merge_requests/create_service_spec.rb
+++ b/spec/services/merge_requests/create_service_spec.rb
@@ -17,7 +17,7 @@ describe MergeRequests::CreateService, services: true do
         }
       end
 
-      let(:service) { MergeRequests::CreateService.new(project, user, opts) }
+      let(:service) { described_class.new(project, user, opts) }
 
       before do
         project.team << [user, :master]
@@ -74,5 +74,14 @@ describe MergeRequests::CreateService, services: true do
         end
       end
     end
+
+    it_behaves_like 'new issuable record that supports slash commands' do
+      let(:default_params) do
+        {
+          source_branch: 'feature',
+          target_branch: 'master'
+        }
+      end
+    end
   end
 end
diff --git a/spec/services/notes/create_service_spec.rb b/spec/services/notes/create_service_spec.rb
index 32753e84b31..36ca7d2bce8 100644
--- a/spec/services/notes/create_service_spec.rb
+++ b/spec/services/notes/create_service_spec.rb
@@ -4,22 +4,31 @@ describe Notes::CreateService, services: true do
   let(:project) { create(:empty_project) }
   let(:issue) { create(:issue, project: project) }
   let(:user) { create(:user) }
+  let(:opts) do
+    { note: 'Awesome comment', noteable_type: 'Issue', noteable_id: issue.id }
+  end
 
   describe '#execute' do
     context "valid params" do
       before do
         project.team << [user, :master]
-        opts = {
-          note: 'Awesome comment',
-          noteable_type: 'Issue',
-          noteable_id: issue.id
-        }
-
         @note = Notes::CreateService.new(project, user, opts).execute
       end
 
       it { expect(@note).to be_valid }
-      it { expect(@note.note).to eq('Awesome comment') }
+      it { expect(@note.note).to eq(opts[:note]) }
+
+      it_behaves_like 'note on noteable that supports slash commands' do
+        let(:noteable) { create(:issue, project: project) }
+      end
+
+      it_behaves_like 'note on noteable that supports slash commands' do
+        let(:noteable) { create(:merge_request, source_project: project) }
+      end
+
+      it_behaves_like 'note on noteable that does not support slash commands' do
+        let(:noteable) { create(:commit, project: project) }
+      end
     end
   end
 
diff --git a/spec/services/slash_commands/interpret_service_spec.rb b/spec/services/slash_commands/interpret_service_spec.rb
new file mode 100644
index 00000000000..fa0f65495ce
--- /dev/null
+++ b/spec/services/slash_commands/interpret_service_spec.rb
@@ -0,0 +1,217 @@
+require 'spec_helper'
+
+describe SlashCommands::InterpretService, services: true do
+  let(:project) { create(:project) }
+  let(:user) { create(:user) }
+  let(:issue) { create(:issue, project: project) }
+  let(:milestone) { create(:milestone, project: project, title: '9.10') }
+  let(:inprogress) { create(:label, project: project, title: 'In Progress') }
+  let(:bug) { create(:label, project: project, title: 'Bug') }
+
+  describe '#command_names' do
+    subject { described_class.command_names }
+
+    it 'returns the known commands' do
+      is_expected.to match_array([
+        :open, :reopen,
+        :close,
+        :assign, :reassign,
+        :unassign, :remove_assignee,
+        :milestone,
+        :remove_milestone,
+        :clear_milestone,
+        :labels, :label,
+        :unlabel, :remove_labels, :remove_label,
+        :clear_labels, :clear_label,
+        :todo,
+        :done,
+        :subscribe,
+        :unsubscribe,
+        :due_date,
+        :clear_due_date
+      ])
+    end
+  end
+
+  describe '#execute' do
+    let(:service) { described_class.new(project, user) }
+
+    shared_examples 'open command' do
+      it 'returns state_event: "open" if content contains /open' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(state_event: 'reopen')
+      end
+    end
+
+    shared_examples 'close command' do
+      it 'returns state_event: "close" if content contains /open' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(state_event: 'close')
+      end
+    end
+
+    shared_examples 'assign command' do
+      it 'fetches assignee and populates assignee_id if content contains /assign' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(assignee_id: user.id)
+      end
+    end
+
+    shared_examples 'milestone command' do
+      it 'fetches milestone and populates milestone_id if content contains /milestone' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(milestone_id: milestone.id)
+      end
+    end
+
+    shared_examples 'label command' do
+      it 'fetches label ids and populates add_label_ids if content contains /label' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(add_label_ids: [bug.id, inprogress.id])
+      end
+    end
+
+    shared_examples 'remove_labels command' do
+      it 'fetches label ids and populates remove_label_ids if content contains /label' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(remove_label_ids: [inprogress.id])
+      end
+    end
+
+    shared_examples 'clear_labels command' do
+      it 'populates label_ids: [] if content contains /clear_labels' do
+        changes = service.execute(content)
+
+        expect(changes).to eq(label_ids: [])
+      end
+    end
+
+    shared_examples 'command returning no changes' do
+      it 'returns an empty hash if content contains /open' do
+        changes = service.execute(content)
+
+        expect(changes).to be_empty
+      end
+    end
+
+    it_behaves_like 'open command' do
+      let(:content) { '/open' }
+    end
+
+    it_behaves_like 'open command' do
+      let(:content) { '/reopen' }
+    end
+
+    it_behaves_like 'close command' do
+      let(:content) { '/close' }
+    end
+
+    it_behaves_like 'assign command' do
+      let(:content) { "/assign @#{user.username}" }
+    end
+
+    it 'does not populate assignee_id if content contains /assign with an unknown user' do
+      changes = service.execute('/assign joe')
+
+      expect(changes).to be_empty
+    end
+
+    it 'does not populate assignee_id if content contains /assign without user' do
+      changes = service.execute('/assign')
+
+      expect(changes).to be_empty
+    end
+
+    it 'populates assignee_id: nil if content contains /unassign' do
+      changes = service.execute('/unassign')
+
+      expect(changes).to eq(assignee_id: nil)
+    end
+
+    it_behaves_like 'milestone command' do
+      let(:content) { "/milestone %#{milestone.title}" }
+    end
+
+    it 'populates milestone_id: nil if content contains /clear_milestone' do
+      changes = service.execute('/clear_milestone')
+
+      expect(changes).to eq(milestone_id: nil)
+    end
+
+    it_behaves_like 'label command' do
+      let(:content) { %(/label ~"#{inprogress.title}" ~#{bug.title} ~unknown) }
+    end
+
+    it_behaves_like 'label command' do
+      let(:content) { %(/labels ~"#{inprogress.title}" ~#{bug.title} ~unknown) }
+    end
+
+    it_behaves_like 'remove_labels command' do
+      let(:content) { %(/unlabel ~"#{inprogress.title}") }
+    end
+
+    it_behaves_like 'remove_labels command' do
+      let(:content) { %(/remove_labels ~"#{inprogress.title}") }
+    end
+
+    it_behaves_like 'remove_labels command' do
+      let(:content) { %(/remove_label ~"#{inprogress.title}") }
+    end
+
+    it_behaves_like 'clear_labels command' do
+      let(:content) { '/clear_labels' }
+    end
+
+    it_behaves_like 'clear_labels command' do
+      let(:content) { '/clear_label' }
+    end
+
+    it 'populates todo: :mark if content contains /todo' do
+      changes = service.execute('/todo')
+
+      expect(changes).to eq(todo_event: 'mark')
+    end
+
+    it 'populates todo: :done if content contains /done' do
+      changes = service.execute('/done')
+
+      expect(changes).to eq(todo_event: 'done')
+    end
+
+    it 'populates subscription: :subscribe if content contains /subscribe' do
+      changes = service.execute('/subscribe')
+
+      expect(changes).to eq(subscription_event: 'subscribe')
+    end
+
+    it 'populates subscription: :unsubscribe if content contains /unsubscribe' do
+      changes = service.execute('/unsubscribe')
+
+      expect(changes).to eq(subscription_event: 'unsubscribe')
+    end
+
+    it 'populates due_date: Time.now.tomorrow if content contains /due_date 2016-08-28' do
+      changes = service.execute('/due_date 2016-08-28')
+
+      expect(changes).to eq(due_date: Date.new(2016, 8, 28))
+    end
+
+    it 'populates due_date: Time.now.tomorrow if content contains /due_date foo' do
+      changes = service.execute('/due_date foo')
+
+      expect(changes).to be_empty
+    end
+
+    it 'populates due_date: nil if content contains /clear_due_date' do
+      changes = service.execute('/clear_due_date')
+
+      expect(changes).to eq(due_date: nil)
+    end
+  end
+end