Add a close issue slack slash command

Adds a slash command in slach for closing issues. See
https://docs.gitlab.com/ee/integration/slash_commands.html
for documentation on the wider feature set.

9 files changed, 218 insertions, 9 deletions

diff --git a/changelogs/unreleased/ce-slack-close-command.yml b/changelogs/unreleased/ce-slack-close-command.yml
new file mode 100644
index 00000000000..c20e623b117
--- /dev/null
+++ b/changelogs/unreleased/ce-slack-close-command.yml
@@ -0,0 +1,5 @@
+---
+title: Add a close issue slack slash command
+merge_request: 32150
+author:
+type: added
diff --git a/doc/integration/slash_commands.md b/doc/integration/slash_commands.md
index 71ea2e25533..86a66dc4569 100644
--- a/doc/integration/slash_commands.md
+++ b/doc/integration/slash_commands.md
@@ -15,6 +15,7 @@ Taking the trigger term as `project-name`, the commands are:
 | `/project-name help` | Shows all available slash commands |
 | `/project-name issue new <title> <shift+return> <description>` | Creates a new issue with title `<title>` and description `<description>` |
 | `/project-name issue show <id>` | Shows the issue with id `<id>` |
+| `/project-name issue close <id>` | Closes the issue with id `<id>` |
 | `/project-name issue search <query>` | Shows up to 5 issues matching `<query>` |
 | `/project-name issue move <id> to <project>` | Moves issue ID `<id>` to `<project>` |
 | `/project-name deploy <from> to <to>` | Deploy from the `<from>` environment to the `<to>` environment |
diff --git a/lib/gitlab/slash_commands/command.rb b/lib/gitlab/slash_commands/command.rb
index 7c963fcf38a..905e0ec5cc1 100644
--- a/lib/gitlab/slash_commands/command.rb
+++ b/lib/gitlab/slash_commands/command.rb
@@ -9,6 +9,7 @@ module Gitlab
           Gitlab::SlashCommands::IssueNew,
           Gitlab::SlashCommands::IssueSearch,
           Gitlab::SlashCommands::IssueMove,
+          Gitlab::SlashCommands::IssueClose,
           Gitlab::SlashCommands::Deploy,
           Gitlab::SlashCommands::Run
         ]
diff --git a/lib/gitlab/slash_commands/issue_close.rb b/lib/gitlab/slash_commands/issue_close.rb
new file mode 100644
index 00000000000..5fcc86e91c4
--- /dev/null
+++ b/lib/gitlab/slash_commands/issue_close.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module SlashCommands
+    class IssueClose < IssueCommand
+      def self.match(text)
+        /\Aissue\s+close\s+#{Issue.reference_prefix}?(?<iid>\d+)/.match(text)
+      end
+
+      def self.help_message
+        "issue close <id>"
+      end
+
+      def self.allowed?(project, user)
+        can?(user, :update_issue, project)
+      end
+
+      def execute(match)
+        issue = find_by_iid(match[:iid])
+
+        return not_found unless issue
+        return presenter(issue).already_closed if issue.closed?
+
+        close_issue(issue: issue)
+
+        presenter(issue).present
+      end
+
+      private
+
+      def close_issue(issue:)
+        Issues::CloseService.new(project, current_user).execute(issue)
+      end
+
+      def presenter(issue)
+        Gitlab::SlashCommands::Presenters::IssueClose.new(issue)
+      end
+
+      def not_found
+        Gitlab::SlashCommands::Presenters::Access.new.not_found
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/slash_commands/presenters/issue_base.rb b/lib/gitlab/slash_commands/presenters/issue_base.rb
index b6db103b82b..08cb82274fd 100644
--- a/lib/gitlab/slash_commands/presenters/issue_base.rb
+++ b/lib/gitlab/slash_commands/presenters/issue_base.rb
@@ -40,6 +40,14 @@ module Gitlab
           ]
         end
 
+        def project_link
+          "[#{project.full_name}](#{project.web_url})"
+        end
+
+        def author_profile_link
+          "[#{author.to_reference}](#{url_for(author)})"
+        end
+
         private
 
         attr_reader :resource
diff --git a/lib/gitlab/slash_commands/presenters/issue_close.rb b/lib/gitlab/slash_commands/presenters/issue_close.rb
new file mode 100644
index 00000000000..b3f24f4296a
--- /dev/null
+++ b/lib/gitlab/slash_commands/presenters/issue_close.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module SlashCommands
+    module Presenters
+      class IssueClose < Presenters::Base
+        include Presenters::IssueBase
+
+        def present
+          if @resource.confidential?
+            ephemeral_response(close_issue)
+          else
+            in_channel_response(close_issue)
+          end
+        end
+
+        def already_closed
+          ephemeral_response(text: "Issue #{@resource.to_reference} is already closed.")
+        end
+
+        private
+
+        def close_issue
+          {
+            attachments: [
+              {
+                title:        "#{@resource.title} · #{@resource.to_reference}",
+                title_link:   resource_url,
+                author_name:  author.name,
+                author_icon:  author.avatar_url,
+                fallback:     "Closed issue #{@resource.to_reference}: #{@resource.title}",
+                pretext:      pretext,
+                color:        color(@resource),
+                fields:       fields,
+                mrkdwn_in: [
+                  :title,
+                  :pretext,
+                  :fields
+                ]
+              }
+            ]
+          }
+        end
+
+        def pretext
+          "I closed an issue on #{author_profile_link}'s behalf: *#{@resource.to_reference}* in #{project_link}"
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/slash_commands/presenters/issue_new.rb b/lib/gitlab/slash_commands/presenters/issue_new.rb
index ac78745ae70..1424a4ac381 100644
--- a/lib/gitlab/slash_commands/presenters/issue_new.rb
+++ b/lib/gitlab/slash_commands/presenters/issue_new.rb
@@ -36,15 +36,7 @@ module Gitlab
         end
 
         def pretext
-          "I created an issue on #{author_profile_link}'s behalf: **#{@resource.to_reference}** in #{project_link}"
-        end
-
-        def project_link
-          "[#{project.full_name}](#{project.web_url})"
-        end
-
-        def author_profile_link
-          "[#{author.to_reference}](#{url_for(author)})"
+          "I created an issue on #{author_profile_link}'s behalf: *#{@resource.to_reference}* in #{project_link}"
         end
       end
     end
diff --git a/spec/lib/gitlab/slash_commands/issue_close_spec.rb b/spec/lib/gitlab/slash_commands/issue_close_spec.rb
new file mode 100644
index 00000000000..c0760ce0ba6
--- /dev/null
+++ b/spec/lib/gitlab/slash_commands/issue_close_spec.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::SlashCommands::IssueClose do
+  describe '#execute' do
+    let(:issue) { create(:issue, project: project) }
+    let(:project) { create(:project) }
+    let(:user) { issue.author }
+    let(:chat_name) { double(:chat_name, user: user) }
+    let(:regex_match) { described_class.match("issue close #{issue.iid}") }
+
+    subject do
+      described_class.new(project, chat_name).execute(regex_match)
+    end
+
+    context 'when the user does not have permission' do
+      let(:chat_name) { double(:chat_name, user: create(:user)) }
+
+      it 'does not allow the user to close the issue' do
+        expect(subject[:response_type]).to be(:ephemeral)
+        expect(subject[:text]).to match("not found")
+        expect(issue.reload).to be_open
+      end
+    end
+
+    context 'the issue exists' do
+      let(:title) { subject[:attachments].first[:title] }
+
+      it 'closes and returns the issue' do
+        expect(subject[:response_type]).to be(:in_channel)
+        expect(issue.reload).to be_closed
+        expect(title).to start_with(issue.title)
+      end
+
+      context 'when its reference is given' do
+        let(:regex_match) { described_class.match("issue close #{issue.to_reference}") }
+
+        it 'closes and returns the issue' do
+          expect(subject[:response_type]).to be(:in_channel)
+          expect(issue.reload).to be_closed
+          expect(title).to start_with(issue.title)
+        end
+      end
+    end
+
+    context 'the issue does not exist' do
+      let(:regex_match) { described_class.match("issue close 2343242") }
+
+      it "returns not found" do
+        expect(subject[:response_type]).to be(:ephemeral)
+        expect(subject[:text]).to match("not found")
+      end
+    end
+
+    context 'when the issue is already closed' do
+      let(:issue) { create(:issue, :closed, project: project) }
+
+      it 'shows the issue' do
+        expect(subject[:response_type]).to be(:ephemeral)
+        expect(issue.reload).to be_closed
+        expect(subject[:text]).to match("already closed")
+      end
+    end
+  end
+
+  describe '.match' do
+    it 'matches the iid' do
+      match = described_class.match("issue close 123")
+
+      expect(match[:iid]).to eq("123")
+    end
+
+    it 'accepts a reference' do
+      match = described_class.match("issue close #{Issue.reference_prefix}123")
+
+      expect(match[:iid]).to eq("123")
+    end
+  end
+end
diff --git a/spec/lib/gitlab/slash_commands/presenters/issue_close_spec.rb b/spec/lib/gitlab/slash_commands/presenters/issue_close_spec.rb
new file mode 100644
index 00000000000..adc13b4ee56
--- /dev/null
+++ b/spec/lib/gitlab/slash_commands/presenters/issue_close_spec.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::SlashCommands::Presenters::IssueClose do
+  let(:project) { create(:project) }
+  let(:issue) { create(:issue, project: project) }
+  let(:attachment) { subject[:attachments].first }
+
+  subject { described_class.new(issue).present }
+
+  it { is_expected.to be_a(Hash) }
+
+  it 'shows the issue' do
+    expect(subject[:response_type]).to be(:in_channel)
+    expect(subject).to have_key(:attachments)
+    expect(attachment[:title]).to start_with(issue.title)
+  end
+
+  context 'confidential issue' do
+    let(:issue) { create(:issue, :confidential, project: project) }
+
+    it 'shows an ephemeral response' do
+      expect(subject[:response_type]).to be(:ephemeral)
+    end
+  end
+end