Display slash commands outcome when previewing Markdownadam-separate-slash-commands

Remove slash commands from Markdown preview and display their outcome next to
the text field.
Introduce new "explanation" block to our slash commands DSL.
Introduce optional "parse_params" block to slash commands DSL that allows to
process a parameter before it is passed to "explanation" or "command" blocks.
Pass path for previewing Markdown as "data" attribute instead of setting
a variable on "window".

5 files changed, 390 insertions, 17 deletions

diff --git a/spec/lib/gitlab/slash_commands/command_definition_spec.rb b/spec/lib/gitlab/slash_commands/command_definition_spec.rb
index c9c2f314e57..5b9173d3d3f 100644
--- a/spec/lib/gitlab/slash_commands/command_definition_spec.rb
+++ b/spec/lib/gitlab/slash_commands/command_definition_spec.rb
@@ -167,6 +167,58 @@ describe Gitlab::SlashCommands::CommandDefinition do
             end
           end
         end
+
+        context 'when the command defines parse_params block' do
+          before do
+            subject.parse_params_block = ->(raw) { raw.strip }
+            subject.action_block = ->(parsed) { self.received_arg = parsed }
+          end
+
+          it 'executes the command passing the parsed param' do
+            subject.execute(context, {}, 'something   ')
+
+            expect(context.received_arg).to eq('something')
+          end
+        end
+      end
+    end
+  end
+
+  describe '#explain' do
+    context 'when the command is not available' do
+      before do
+        subject.condition_block = proc { false }
+        subject.explanation = 'Explanation'
+      end
+
+      it 'returns nil' do
+        result = subject.explain({}, {}, nil)
+
+        expect(result).to be_nil
+      end
+    end
+
+    context 'when the explanation is a static string' do
+      before do
+        subject.explanation = 'Explanation'
+      end
+
+      it 'returns this static string' do
+        result = subject.explain({}, {}, nil)
+
+        expect(result).to eq 'Explanation'
+      end
+    end
+
+    context 'when the explanation is dynamic' do
+      before do
+        subject.explanation = proc { |arg| "Dynamic #{arg}" }
+      end
+
+      it 'invokes the proc' do
+        result = subject.explain({}, {}, 'explanation')
+
+        expect(result).to eq 'Dynamic explanation'
       end
     end
   end
diff --git a/spec/lib/gitlab/slash_commands/dsl_spec.rb b/spec/lib/gitlab/slash_commands/dsl_spec.rb
index 2763d950716..33b49a5ddf9 100644
--- a/spec/lib/gitlab/slash_commands/dsl_spec.rb
+++ b/spec/lib/gitlab/slash_commands/dsl_spec.rb
@@ -11,67 +11,99 @@ describe Gitlab::SlashCommands::Dsl do
       end
 
       params 'The first argument'
-      command :one_arg, :once, :first do |arg1|
-        arg1
+      explanation 'Static explanation'
+      command :explanation_with_aliases, :once, :first do |arg|
+        arg
       end
 
       desc do
         "A dynamic description for #{noteable.upcase}"
       end
       params 'The first argument', 'The second argument'
-      command :two_args do |arg1, arg2|
-        [arg1, arg2]
+      command :dynamic_description do |args|
+        args.split
       end
 
       command :cc
 
+      explanation do |arg|
+        "Action does something with #{arg}"
+      end
       condition do
         project == 'foo'
       end
       command :cond_action do |arg|
         arg
       end
+
+      parse_params do |raw_arg|
+        raw_arg.strip
+      end
+      command :with_params_parsing do |parsed|
+        parsed
+      end
     end
   end
 
   describe '.command_definitions' do
     it 'returns an array with commands definitions' do
-      no_args_def, one_arg_def, two_args_def, cc_def, cond_action_def = DummyClass.command_definitions
+      no_args_def, explanation_with_aliases_def, dynamic_description_def,
+      cc_def, cond_action_def, with_params_parsing_def =
+        DummyClass.command_definitions
 
       expect(no_args_def.name).to eq(:no_args)
       expect(no_args_def.aliases).to eq([:none])
       expect(no_args_def.description).to eq('A command with no args')
+      expect(no_args_def.explanation).to eq('')
       expect(no_args_def.params).to eq([])
       expect(no_args_def.condition_block).to be_nil
       expect(no_args_def.action_block).to be_a_kind_of(Proc)
+      expect(no_args_def.parse_params_block).to be_nil
 
-      expect(one_arg_def.name).to eq(:one_arg)
-      expect(one_arg_def.aliases).to eq([:once, :first])
-      expect(one_arg_def.description).to eq('')
-      expect(one_arg_def.params).to eq(['The first argument'])
-      expect(one_arg_def.condition_block).to be_nil
-      expect(one_arg_def.action_block).to be_a_kind_of(Proc)
+      expect(explanation_with_aliases_def.name).to eq(:explanation_with_aliases)
+      expect(explanation_with_aliases_def.aliases).to eq([:once, :first])
+      expect(explanation_with_aliases_def.description).to eq('')
+      expect(explanation_with_aliases_def.explanation).to eq('Static explanation')
+      expect(explanation_with_aliases_def.params).to eq(['The first argument'])
+      expect(explanation_with_aliases_def.condition_block).to be_nil
+      expect(explanation_with_aliases_def.action_block).to be_a_kind_of(Proc)
+      expect(explanation_with_aliases_def.parse_params_block).to be_nil
 
-      expect(two_args_def.name).to eq(:two_args)
-      expect(two_args_def.aliases).to eq([])
-      expect(two_args_def.to_h(noteable: "issue")[:description]).to eq('A dynamic description for ISSUE')
-      expect(two_args_def.params).to eq(['The first argument', 'The second argument'])
-      expect(two_args_def.condition_block).to be_nil
-      expect(two_args_def.action_block).to be_a_kind_of(Proc)
+      expect(dynamic_description_def.name).to eq(:dynamic_description)
+      expect(dynamic_description_def.aliases).to eq([])
+      expect(dynamic_description_def.to_h(noteable: 'issue')[:description]).to eq('A dynamic description for ISSUE')
+      expect(dynamic_description_def.explanation).to eq('')
+      expect(dynamic_description_def.params).to eq(['The first argument', 'The second argument'])
+      expect(dynamic_description_def.condition_block).to be_nil
+      expect(dynamic_description_def.action_block).to be_a_kind_of(Proc)
+      expect(dynamic_description_def.parse_params_block).to be_nil
 
       expect(cc_def.name).to eq(:cc)
       expect(cc_def.aliases).to eq([])
       expect(cc_def.description).to eq('')
+      expect(cc_def.explanation).to eq('')
       expect(cc_def.params).to eq([])
       expect(cc_def.condition_block).to be_nil
       expect(cc_def.action_block).to be_nil
+      expect(cc_def.parse_params_block).to be_nil
 
       expect(cond_action_def.name).to eq(:cond_action)
       expect(cond_action_def.aliases).to eq([])
       expect(cond_action_def.description).to eq('')
+      expect(cond_action_def.explanation).to be_a_kind_of(Proc)
       expect(cond_action_def.params).to eq([])
       expect(cond_action_def.condition_block).to be_a_kind_of(Proc)
       expect(cond_action_def.action_block).to be_a_kind_of(Proc)
+      expect(cond_action_def.parse_params_block).to be_nil
+
+      expect(with_params_parsing_def.name).to eq(:with_params_parsing)
+      expect(with_params_parsing_def.aliases).to eq([])
+      expect(with_params_parsing_def.description).to eq('')
+      expect(with_params_parsing_def.explanation).to eq('')
+      expect(with_params_parsing_def.params).to eq([])
+      expect(with_params_parsing_def.condition_block).to be_nil
+      expect(with_params_parsing_def.action_block).to be_a_kind_of(Proc)
+      expect(with_params_parsing_def.parse_params_block).to be_a_kind_of(Proc)
     end
   end
 end
diff --git a/spec/services/preview_markdown_service_spec.rb b/spec/services/preview_markdown_service_spec.rb
new file mode 100644
index 00000000000..b2fb5c91313
--- /dev/null
+++ b/spec/services/preview_markdown_service_spec.rb
@@ -0,0 +1,67 @@
+require 'spec_helper'
+
+describe PreviewMarkdownService do
+  let(:user) { create(:user) }
+  let(:project) { create(:empty_project) }
+
+  before do
+    project.add_developer(user)
+  end
+
+  describe 'user references' do
+    let(:params) { { text: "Take a look #{user.to_reference}" } }
+    let(:service) { described_class.new(project, user, params) }
+
+    it 'returns users referenced in text' do
+      result = service.execute
+
+      expect(result[:users]).to eq [user.username]
+    end
+  end
+
+  context 'new note with slash commands' do
+    let(:issue) { create(:issue, project: project) }
+    let(:params) do
+      {
+        text: "Please do it\n/assign #{user.to_reference}",
+        slash_commands_target_type: 'Issue',
+        slash_commands_target_id: issue.id
+      }
+    end
+    let(:service) { described_class.new(project, user, params) }
+
+    it 'removes slash commands from text' do
+      result = service.execute
+
+      expect(result[:text]).to eq 'Please do it'
+    end
+
+    it 'explains slash commands effect' do
+      result = service.execute
+
+      expect(result[:commands]).to eq "Assigns #{user.to_reference}."
+    end
+  end
+
+  context 'merge request description' do
+    let(:params) do
+      {
+        text: "My work\n/estimate 2y",
+        slash_commands_target_type: 'MergeRequest'
+      }
+    end
+    let(:service) { described_class.new(project, user, params) }
+
+    it 'removes slash commands from text' do
+      result = service.execute
+
+      expect(result[:text]).to eq 'My work'
+    end
+
+    it 'explains slash commands effect' do
+      result = service.execute
+
+      expect(result[:commands]).to eq 'Sets time estimate to 2y.'
+    end    
+  end
+end
diff --git a/spec/services/slash_commands/interpret_service_spec.rb b/spec/services/slash_commands/interpret_service_spec.rb
index 29e65fe7ce6..46cfac4a128 100644
--- a/spec/services/slash_commands/interpret_service_spec.rb
+++ b/spec/services/slash_commands/interpret_service_spec.rb
@@ -798,4 +798,211 @@ describe SlashCommands::InterpretService, services: true do
       end
     end
   end
+
+  describe '#explain' do
+    let(:service) { described_class.new(project, developer) }
+    let(:merge_request) { create(:merge_request, source_project: project) }
+
+    describe 'close command' do
+      let(:content) { '/close' }
+
+      it 'includes issuable name' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(['Closes this issue.'])
+      end
+    end
+
+    describe 'reopen command' do
+      let(:content) { '/reopen' }
+      let(:merge_request) { create(:merge_request, :closed, source_project: project) }
+
+      it 'includes issuable name' do
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Reopens this merge request.'])
+      end
+    end
+
+    describe 'title command' do
+      let(:content) { '/title This is new title' }
+
+      it 'includes new title' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(['Changes the title to "This is new title".'])
+      end
+    end
+
+    describe 'assign command' do
+      let(:content) { "/assign @#{developer.username} do it!" }
+
+      it 'includes only the user reference' do
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(["Assigns @#{developer.username}."])
+      end
+    end
+
+    describe 'unassign command' do
+      let(:content) { '/unassign' }
+      let(:issue) { create(:issue, project: project, assignee: developer) }
+
+      it 'includes current assignee reference' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(["Removes assignee @#{developer.username}."])
+      end
+    end
+
+    describe 'milestone command' do
+      let(:content) { '/milestone %wrong-milestone' }
+      let!(:milestone) { create(:milestone, project: project, title: '9.10') }
+
+      it 'is empty when milestone reference is wrong' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq([])
+      end
+    end
+
+    describe 'remove milestone command' do
+      let(:content) { '/remove_milestone' }
+      let(:merge_request) { create(:merge_request, source_project: project, milestone: milestone) }
+
+      it 'includes current milestone name' do
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Removes %"9.10" milestone.'])
+      end
+    end
+
+    describe 'label command' do
+      let(:content) { '/label ~missing' }
+      let!(:label) { create(:label, project: project) }
+
+      it 'is empty when there are no correct labels' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq([])
+      end
+    end
+
+    describe 'unlabel command' do
+      let(:content) { '/unlabel' }
+
+      it 'says all labels if no parameter provided' do
+        merge_request.update!(label_ids: [bug.id])
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Removes all labels.'])
+      end
+    end
+
+    describe 'relabel command' do
+      let(:content) { '/relabel Bug' }
+      let!(:bug) { create(:label, project: project, title: 'Bug') }
+      let(:feature) { create(:label, project: project, title: 'Feature') }
+
+      it 'includes label name' do
+        issue.update!(label_ids: [feature.id])
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(["Replaces all labels with ~#{bug.id} label."])
+      end
+    end
+
+    describe 'subscribe command' do
+      let(:content) { '/subscribe' }
+
+      it 'includes issuable name' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(['Subscribes to this issue.'])
+      end
+    end
+
+    describe 'unsubscribe command' do
+      let(:content) { '/unsubscribe' }
+
+      it 'includes issuable name' do
+        merge_request.subscribe(developer, project)
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Unsubscribes from this merge request.'])
+      end
+    end
+
+    describe 'due command' do
+      let(:content) { '/due April 1st 2016' }
+
+      it 'includes the date' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(['Sets the due date to Apr 1, 2016.'])
+      end
+    end
+
+    describe 'wip command' do
+      let(:content) { '/wip' }
+
+      it 'includes the new status' do
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Marks this merge request as Work In Progress.'])
+      end
+    end
+
+    describe 'award command' do
+      let(:content) { '/award :confetti_ball: ' }
+
+      it 'includes the emoji' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(['Toggles :confetti_ball: emoji award.'])
+      end
+    end
+
+    describe 'estimate command' do
+      let(:content) { '/estimate 79d' }
+
+      it 'includes the formatted duration' do
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Sets time estimate to 3mo 3w 4d.'])
+      end
+    end
+
+    describe 'spend command' do
+      let(:content) { '/spend -120m' }
+
+      it 'includes the formatted duration and proper verb' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(['Substracts 2h spent time.'])
+      end
+    end
+
+    describe 'target branch command' do
+      let(:content) { '/target_branch my-feature ' }
+
+      it 'includes the branch name' do
+        _, explanations = service.explain(content, merge_request)
+
+        expect(explanations).to eq(['Sets target branch to my-feature.'])
+      end
+    end
+
+    describe 'board move command' do
+      let(:content) { '/board_move ~bug' }
+      let!(:bug) { create(:label, project: project, title: 'bug') }
+      let!(:board) { create(:board, project: project) }
+
+      it 'includes the label name' do
+        _, explanations = service.explain(content, issue)
+
+        expect(explanations).to eq(["Moves issue to ~#{bug.id} column in the board."])
+      end
+    end
+  end
 end
diff --git a/spec/support/features/issuable_slash_commands_shared_examples.rb b/spec/support/features/issuable_slash_commands_shared_examples.rb
index 5bbe36d9b7f..6efcdd7a1de 100644
--- a/spec/support/features/issuable_slash_commands_shared_examples.rb
+++ b/spec/support/features/issuable_slash_commands_shared_examples.rb
@@ -257,4 +257,19 @@ shared_examples 'issuable record that supports slash commands in its description
       end
     end
   end
+
+  describe "preview of note on #{issuable_type}" do
+    it 'removes slash commands from note and explains them' do
+      visit public_send("namespace_project_#{issuable_type}_path", project.namespace, project, issuable)
+
+      page.within('.js-main-target-form') do
+        fill_in 'note[note]', with: "Awesome!\n/assign @bob "
+        click_on 'Preview'
+
+        expect(page).to have_content 'Awesome!'
+        expect(page).not_to have_content '/assign @bob'
+        expect(page).to have_content 'Assigns @bob.'
+      end
+    end
+  end
 end