Limit autocomplete menu to applied labels

6 files changed, 199 insertions, 26 deletions

diff --git a/app/assets/javascripts/gfm_auto_complete.js b/app/assets/javascripts/gfm_auto_complete.js
index a642464c920..d918d80df8d 100644
--- a/app/assets/javascripts/gfm_auto_complete.js
+++ b/app/assets/javascripts/gfm_auto_complete.js
@@ -287,6 +287,10 @@ class GfmAutoComplete {
   }
 
   setupLabels($input) {
+    const fetchData = this.fetchData.bind(this);
+    const LABEL_COMMAND = { LABEL: '/label', UNLABEL: '/unlabel', RELABEL: '/relabel' };
+    let command = '';
+
     $input.atwho({
       at: '~',
       alias: 'labels',
@@ -309,8 +313,45 @@ class GfmAutoComplete {
             title: sanitize(m.title),
             color: m.color,
             search: m.title,
+            set: m.set,
           }));
         },
+        matcher(flag, subtext) {
+          const match = GfmAutoComplete.defaultMatcher(flag, subtext, this.app.controllers);
+          const subtextNodes = subtext.split(/\n+/g).pop().split(GfmAutoComplete.regexSubtext);
+
+          // Check if ~ is followed by '/label', '/relabel' or '/unlabel' commands.
+          command = subtextNodes.find((node) => {
+            if (node === LABEL_COMMAND.LABEL ||
+                node === LABEL_COMMAND.RELABEL ||
+                node === LABEL_COMMAND.UNLABEL) { return node; }
+            return null;
+          });
+
+          return match && match.length ? match[1] : null;
+        },
+        filter(query, data, searchKey) {
+          if (GfmAutoComplete.isLoading(data)) {
+            fetchData(this.$inputor, this.at);
+            return data;
+          }
+
+          if (data === GfmAutoComplete.defaultLoadingData) {
+            return $.fn.atwho.default.callbacks.filter(query, data, searchKey);
+          }
+
+          // The `LABEL_COMMAND.RELABEL` is intentionally skipped
+          // because we want to return all the labels (unfiltered) for that command.
+          if (command === LABEL_COMMAND.LABEL) {
+            // Return labels with set: undefined.
+            return data.filter(label => !label.set);
+          } else if (command === LABEL_COMMAND.UNLABEL) {
+            // Return labels with set: true.
+            return data.filter(label => label.set);
+          }
+
+          return data;
+        },
       },
     });
   }
@@ -346,20 +387,7 @@ class GfmAutoComplete {
         return resultantValue;
       },
       matcher(flag, subtext) {
-        // The below is taken from At.js source
-        // Tweaked to commands to start without a space only if char before is a non-word character
-        // https://github.com/ichord/At.js
-        const atSymbolsWithBar = Object.keys(this.app.controllers).join('|');
-        const atSymbolsWithoutBar = Object.keys(this.app.controllers).join('');
-        const targetSubtext = subtext.split(/\s+/g).pop();
-        const resultantFlag = flag.replace(/[-[\]/{}()*+?.\\^$|]/g, '\\$&');
-
-        const accentAChar = decodeURI('%C3%80');
-        const accentYChar = decodeURI('%C3%BF');
-
-        const regexp = new RegExp(`^(?:\\B|[^a-zA-Z0-9_${atSymbolsWithoutBar}]|\\s)${resultantFlag}(?!${atSymbolsWithBar})((?:[A-Za-z${accentAChar}-${accentYChar}0-9_'.+-]|[^\\x00-\\x7a])*)$`, 'gi');
-
-        const match = regexp.exec(targetSubtext);
+        const match = GfmAutoComplete.defaultMatcher(flag, subtext, this.app.controllers);
 
         if (match) {
           return match[1];
@@ -420,8 +448,27 @@ class GfmAutoComplete {
     return dataToInspect &&
       (dataToInspect === loadingState || dataToInspect.name === loadingState);
   }
+
+  static defaultMatcher(flag, subtext, controllers) {
+    // The below is taken from At.js source
+    // Tweaked to commands to start without a space only if char before is a non-word character
+    // https://github.com/ichord/At.js
+    const atSymbolsWithBar = Object.keys(controllers).join('|');
+    const atSymbolsWithoutBar = Object.keys(controllers).join('');
+    const targetSubtext = subtext.split(GfmAutoComplete.regexSubtext).pop();
+    const resultantFlag = flag.replace(/[-[\]/{}()*+?.\\^$|]/g, '\\$&');
+
+    const accentAChar = decodeURI('%C3%80');
+    const accentYChar = decodeURI('%C3%BF');
+
+    const regexp = new RegExp(`^(?:\\B|[^a-zA-Z0-9_${atSymbolsWithoutBar}]|\\s)${resultantFlag}(?!${atSymbolsWithBar})((?:[A-Za-z${accentAChar}-${accentYChar}0-9_'.+-]|[^\\x00-\\x7a])*)$`, 'gi');
+
+    return regexp.exec(targetSubtext);
+  }
 }
 
+GfmAutoComplete.regexSubtext = new RegExp(/\s+/g);
+
 GfmAutoComplete.defaultLoadingData = ['loading'];
 
 GfmAutoComplete.atTypeMap = {
diff --git a/app/controllers/projects/autocomplete_sources_controller.rb b/app/controllers/projects/autocomplete_sources_controller.rb
index ffb54390965..45c66b63ea5 100644
--- a/app/controllers/projects/autocomplete_sources_controller.rb
+++ b/app/controllers/projects/autocomplete_sources_controller.rb
@@ -2,7 +2,7 @@ class Projects::AutocompleteSourcesController < Projects::ApplicationController
   before_action :load_autocomplete_service, except: [:members]
 
   def members
-    render json: ::Projects::ParticipantsService.new(@project, current_user).execute(noteable)
+    render json: ::Projects::ParticipantsService.new(@project, current_user).execute(target)
   end
 
   def issues
@@ -14,7 +14,7 @@ class Projects::AutocompleteSourcesController < Projects::ApplicationController
   end
 
   def labels
-    render json: @autocomplete_service.labels
+    render json: @autocomplete_service.labels(target)
   end
 
   def milestones
@@ -22,7 +22,7 @@ class Projects::AutocompleteSourcesController < Projects::ApplicationController
   end
 
   def commands
-    render json: @autocomplete_service.commands(noteable, params[:type])
+    render json: @autocomplete_service.commands(target, params[:type])
   end
 
   private
@@ -31,13 +31,13 @@ class Projects::AutocompleteSourcesController < Projects::ApplicationController
     @autocomplete_service = ::Projects::AutocompleteService.new(@project, current_user)
   end
 
-  def noteable
-    case params[:type]
-    when 'Issue'
+  def target
+    case params[:type]&.downcase
+    when 'issue'
       IssuesFinder.new(current_user, project_id: @project.id).execute.find_by(iid: params[:type_id])
-    when 'MergeRequest'
+    when 'mergerequest'
       MergeRequestsFinder.new(current_user, project_id: @project.id).execute.find_by(iid: params[:type_id])
-    when 'Commit'
+    when 'commit'
       @project.commit(params[:type_id])
     end
   end
diff --git a/app/services/projects/autocomplete_service.rb b/app/services/projects/autocomplete_service.rb
index 724a77c873a..1ae2c40872a 100644
--- a/app/services/projects/autocomplete_service.rb
+++ b/app/services/projects/autocomplete_service.rb
@@ -20,8 +20,23 @@ module Projects
       MergeRequestsFinder.new(current_user, project_id: project.id, state: 'opened').execute.select([:iid, :title])
     end
 
-    def labels
-      LabelsFinder.new(current_user, project_id: project.id).execute.select([:title, :color])
+    def labels(target = nil)
+      labels = LabelsFinder.new(current_user, project_id: project.id).execute.select([:color, :title])
+
+      return labels unless target&.respond_to?(:labels)
+
+      issuable_label_titles = target.labels.pluck(:title)
+
+      if issuable_label_titles
+        labels = labels.as_json(only: [:title, :color])
+
+        issuable_label_titles.each do |issuable_label_title|
+          found_label = labels.find { |label| label['title'] == issuable_label_title }
+          found_label[:set] = true if found_label
+        end
+      end
+
+      labels
     end
 
     def commands(noteable, type)
@@ -33,7 +48,7 @@ module Projects
           @project.merge_requests.build
         end
 
-      return [] unless noteable && noteable.is_a?(Issuable)
+      return [] unless noteable&.is_a?(Issuable)
 
       opts = {
         project: project,
diff --git a/app/views/layouts/_init_auto_complete.html.haml b/app/views/layouts/_init_auto_complete.html.haml
index fe0ec35d003..4276e6ee4bb 100644
--- a/app/views/layouts/_init_auto_complete.html.haml
+++ b/app/views/layouts/_init_auto_complete.html.haml
@@ -10,7 +10,7 @@
       members: "#{members_project_autocomplete_sources_path(project, type: noteable_type, type_id: params[:id])}",
       issues: "#{issues_project_autocomplete_sources_path(project)}",
       mergeRequests: "#{merge_requests_project_autocomplete_sources_path(project)}",
-      labels: "#{labels_project_autocomplete_sources_path(project)}",
+      labels: "#{labels_project_autocomplete_sources_path(project, type: noteable_type, type_id: params[:id])}",
       milestones: "#{milestones_project_autocomplete_sources_path(project)}",
       commands: "#{commands_project_autocomplete_sources_path(project, type: noteable_type, type_id: params[:id])}"
     };
diff --git a/changelogs/unreleased/22680-unlabel-slash-command-limit-autocomplete-to-applied-labels.yml b/changelogs/unreleased/22680-unlabel-slash-command-limit-autocomplete-to-applied-labels.yml
new file mode 100644
index 00000000000..6d7f8655282
--- /dev/null
+++ b/changelogs/unreleased/22680-unlabel-slash-command-limit-autocomplete-to-applied-labels.yml
@@ -0,0 +1,5 @@
+---
+title: Limit autocomplete menu to applied labels
+merge_request: 11110
+author: Vitaliy @blackst0ne Klachkov
+type: added
diff --git a/spec/features/issues/gfm_autocomplete_spec.rb b/spec/features/issues/gfm_autocomplete_spec.rb
index 95d637265e0..c31b636d67f 100644
--- a/spec/features/issues/gfm_autocomplete_spec.rb
+++ b/spec/features/issues/gfm_autocomplete_spec.rb
@@ -220,6 +220,89 @@ feature 'GFM autocomplete', :js do
     end
   end
 
+  # This context has jsut one example in each contexts in order to improve spec performance.
+  context 'labels' do
+    let!(:backend)          { create(:label, project: project, title: 'backend') }
+    let!(:bug)              { create(:label, project: project, title: 'bug') }
+    let!(:feature_proposal) { create(:label, project: project, title: 'feature proposal') }
+
+    context 'when no labels are assigned' do
+      it 'shows labels' do
+        note = find('#note-body')
+
+        # It should show all the labels on "~".
+        type(note, '~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show all the labels on "/label ~".
+        type(note, '/label ~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show all the labels on "/relabel ~".
+        type(note, '/relabel ~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show no labels on "/unlabel ~".
+        type(note, '/unlabel ~')
+        expect_labels(not_shown: [backend, bug, feature_proposal])
+      end
+    end
+
+    context 'when some labels are assigned' do
+      before do
+        issue.labels << [backend]
+      end
+
+      it 'shows labels' do
+        note = find('#note-body')
+
+        # It should show all the labels on "~".
+        type(note, '~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show only unset labels on "/label ~".
+        type(note, '/label ~')
+        expect_labels(shown: [bug, feature_proposal], not_shown: [backend])
+
+        # It should show all the labels on "/relabel ~".
+        type(note, '/relabel ~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show only set labels on "/unlabel ~".
+        type(note, '/unlabel ~')
+        expect_labels(shown: [backend], not_shown: [bug, feature_proposal])
+      end
+    end
+
+    context 'when all labels are assigned' do
+      before do
+        issue.labels << [backend, bug, feature_proposal]
+      end
+
+      it 'shows labels' do
+        note = find('#note-body')
+
+        # It should show all the labels on "~".
+        type(note, '~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show no labels on "/label ~".
+        type(note, '/label ~')
+        expect_labels(not_shown: [backend, bug, feature_proposal])
+
+        # It should show all the labels on "/relabel ~".
+        type(note, '/relabel ~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+
+        # It should show all the labels on "/unlabel ~".
+        type(note, '/unlabel ~')
+        expect_labels(shown: [backend, bug, feature_proposal])
+      end
+    end
+  end
+
+  private
+
   def expect_to_wrap(should_wrap, item, note, value)
     expect(item).to have_content(value)
     expect(item).not_to have_content("\"#{value}\"")
@@ -232,4 +315,27 @@ feature 'GFM autocomplete', :js do
       expect(note.value).not_to include("\"#{value}\"")
     end
   end
+
+  def expect_labels(shown: nil, not_shown: nil)
+    page.within('.atwho-container') do
+      if shown
+        expect(page).to have_selector('.atwho-view li', count: shown.size)
+        shown.each { |label| expect(page).to have_content(label.title) }
+      end
+
+      if not_shown
+        expect(page).not_to have_selector('.atwho-view li') unless shown
+        not_shown.each { |label| expect(page).not_to have_content(label.title) }
+      end
+    end
+  end
+
+  # `note` is a textarea where the given text should be typed.
+  # We don't want to find it each time this function gets called.
+  def type(note, text)
+    page.within('.timeline-content-form') do
+      note.set('')
+      note.native.send_keys(text)
+    end
+  end
 end