Merge branch 'todos-api' into 'master'

Add Todos API

* Closes #14068
* Closes #14675 

- [x] Implementation
- [x]  Tests
- [x] Documentation
- [x] Changelog

See merge request !3188

3 files changed, 108 insertions, 0 deletions

diff --git a/lib/api/api.rb b/lib/api/api.rb
index c3fff8b2f8f..3d7d67510a8 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -58,6 +58,7 @@ module API
     mount ::API::SystemHooks
     mount ::API::Tags
     mount ::API::Templates
+    mount ::API::Todos
     mount ::API::Triggers
     mount ::API::Users
     mount ::API::Variables
diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index 4e2a43e45e2..8cc4368b5c2 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -272,6 +272,31 @@ module API
       expose :id, :project_id, :group_id, :group_access
     end
 
+    class Todo < Grape::Entity
+      expose :id
+      expose :project, using: Entities::BasicProjectDetails
+      expose :author, using: Entities::UserBasic
+      expose :action_name
+      expose :target_type
+
+      expose :target do |todo, options|
+        Entities.const_get(todo.target_type).represent(todo.target, options)
+      end
+
+      expose :target_url do |todo, options|
+        target_type   = todo.target_type.underscore
+        target_url    = "namespace_project_#{target_type}_url"
+        target_anchor = "note_#{todo.note_id}" if todo.note_id?
+
+        Gitlab::Application.routes.url_helpers.public_send(target_url,
+          todo.project.namespace, todo.project, todo.target, anchor: target_anchor)
+      end
+
+      expose :body
+      expose :state
+      expose :created_at
+    end
+
     class Namespace < Grape::Entity
       expose :id, :path, :kind
     end
diff --git a/lib/api/todos.rb b/lib/api/todos.rb
new file mode 100644
index 00000000000..2a6bfa98ca4
--- /dev/null
+++ b/lib/api/todos.rb
@@ -0,0 +1,82 @@
+module API
+  # Todos API
+  class Todos < Grape::API
+    before { authenticate! }
+
+    ISSUABLE_TYPES = {
+      'merge_requests' => ->(id) { user_project.merge_requests.find(id) },
+      'issues' => ->(id) { find_project_issue(id) }
+    }
+
+    resource :projects do
+      ISSUABLE_TYPES.each do |type, finder|
+        type_id_str = "#{type.singularize}_id".to_sym
+
+        # Create a todo on an issuable
+        #
+        # Parameters:
+        #   id (required) - The ID of a project
+        #   issuable_id (required) - The ID of an issuable
+        # Example Request:
+        #   POST /projects/:id/issues/:issuable_id/todo
+        #   POST /projects/:id/merge_requests/:issuable_id/todo
+        post ":id/#{type}/:#{type_id_str}/todo" do
+          issuable = instance_exec(params[type_id_str], &finder)
+          todo = TodoService.new.mark_todo(issuable, current_user).first
+
+          if todo
+            present todo, with: Entities::Todo, current_user: current_user
+          else
+            not_modified!
+          end
+        end
+      end
+    end
+
+    resource :todos do
+      helpers do
+        def find_todos
+          TodosFinder.new(current_user, params).execute
+        end
+      end
+
+      # Get a todo list
+      #
+      # Example Request:
+      #  GET /todos
+      #
+      get do
+        todos = find_todos
+
+        present paginate(todos), with: Entities::Todo, current_user: current_user
+      end
+
+      # Mark a todo as done
+      #
+      # Parameters:
+      #   id: (required) - The ID of the todo being marked as done
+      #
+      # Example Request:
+      #  DELETE /todos/:id
+      #
+      delete ':id' do
+        todo = current_user.todos.find(params[:id])
+        todo.done
+
+        present todo, with: Entities::Todo, current_user: current_user
+      end
+
+      # Mark all todos as done
+      #
+      # Example Request:
+      #  DELETE /todos
+      #
+      delete do
+        todos = find_todos
+        todos.each(&:done)
+
+        present paginate(Kaminari.paginate_array(todos)), with: Entities::Todo, current_user: current_user
+      end
+    end
+  end
+end