module Gitlab
  # Milestones API
  class Milestones < Grape::API
    before { authenticate! }

    resource :projects do

      helpers do
        # If an error occurs this helper method handles error codes for a given milestone
        #
        # Parameters:
        #   milestone_errors (required) - The erros collection of a milestone
        #
        def handle_milestone_errors(milestone_errors)
          if milestone_errors[:title].any?
            error!(milestone_errors[:title], 400)
          end
        end
      end

      # Get a list of project milestones
      #
      # Parameters:
      #   id (required) - The ID of a project
      # Example Request:
      #   GET /projects/:id/milestones
      get ":id/milestones" do
        authorize! :read_milestone, user_project

        present paginate(user_project.milestones), with: Entities::Milestone
      end

      # Get a single project milestone
      #
      # Parameters:
      #   id (required) - The ID of a project
      #   milestone_id (required) - The ID of a project milestone
      # Example Request:
      #   GET /projects/:id/milestones/:milestone_id
      get ":id/milestones/:milestone_id" do
        authorize! :read_milestone, user_project

        @milestone = user_project.milestones.find(params[:milestone_id])
        present @milestone, with: Entities::Milestone
      end

      # Create a new project milestone
      #
      # Parameters:
      #   id (required) - The ID of the project
      #   title (required) - The title of the milestone
      #   description (optional) - The description of the milestone
      #   due_date (optional) - The due date of the milestone
      # Example Request:
      #   POST /projects/:id/milestones
      post ":id/milestones" do
        authorize! :admin_milestone, user_project

        attrs = attributes_for_keys [:title, :description, :due_date]
        @milestone = user_project.milestones.new attrs
        if @milestone.save
          present @milestone, with: Entities::Milestone
        else
          handle_milestone_errors(@milestone.errors)
          not_found!
        end
      end

      # Update an existing project milestone
      #
      # Parameters:
      #   id (required) - The ID of a project
      #   milestone_id (required) - The ID of a project milestone
      #   title (optional) - The title of a milestone
      #   description (optional) - The description of a milestone
      #   due_date (optional) - The due date of a milestone
      #   closed (optional) - The status of the milestone
      # Example Request:
      #   PUT /projects/:id/milestones/:milestone_id
      put ":id/milestones/:milestone_id" do
        authorize! :admin_milestone, user_project

        @milestone = user_project.milestones.find(params[:milestone_id])
        attrs = attributes_for_keys [:title, :description, :due_date, :closed]
        if @milestone.update_attributes attrs
          present @milestone, with: Entities::Milestone
        else
          handle_milestone_errors(@milestone.errors)
          not_found!
        end
      end
    end
  end
end