module API
  class Discussions < Grape::API
    include PaginationParams
    helpers ::API::Helpers::NotesHelpers

    before { authenticate! }

    NOTEABLE_TYPES = [Issue, Snippet, MergeRequest, Commit].freeze

    NOTEABLE_TYPES.each do |noteable_type|
      parent_type = noteable_type.parent_class.to_s.underscore
      noteables_str = noteable_type.to_s.underscore.pluralize
      noteables_path = noteable_type == Commit ? "repository/#{noteables_str}" : noteables_str

      params do
        requires :id, type: String, desc: "The ID of a #{parent_type}"
      end
      resource parent_type.pluralize.to_sym, requirements: API::PROJECT_ENDPOINT_REQUIREMENTS do
        desc "Get a list of #{noteable_type.to_s.downcase} discussions" do
          success Entities::Discussion
        end
        params do
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
          use :pagination
        end
        get ":id/#{noteables_path}/:noteable_id/discussions" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])

          notes = noteable.notes
            .inc_relations_for_view
            .includes(:noteable)
            .fresh

          notes = notes.reject { |n| n.cross_reference_not_visible_for?(current_user) }
          discussions = Kaminari.paginate_array(Discussion.build_collection(notes, noteable))

          present paginate(discussions), with: Entities::Discussion
        end

        desc "Get a single #{noteable_type.to_s.downcase} discussion" do
          success Entities::Discussion
        end
        params do
          requires :discussion_id, type: String, desc: 'The ID of a discussion'
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
        end
        get ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])
          notes = readable_discussion_notes(noteable, params[:discussion_id])

          if notes.empty?
            break not_found!("Discussion")
          end

          discussion = Discussion.build(notes, noteable)

          present discussion, with: Entities::Discussion
        end

        desc "Create a new #{noteable_type.to_s.downcase} discussion" do
          success Entities::Discussion
        end
        params do
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
          requires :body, type: String, desc: 'The content of a note'
          optional :created_at, type: String, desc: 'The creation date of the note'
          optional :position, type: Hash do
            requires :base_sha, type: String, desc: 'Base commit SHA in the source branch'
            requires :start_sha, type: String, desc: 'SHA referencing commit in target branch'
            requires :head_sha, type: String, desc: 'SHA referencing HEAD of this merge request'
            requires :position_type, type: String, desc: 'Type of the position reference', values: %w(text image)
            optional :new_path, type: String, desc: 'File path after change'
            optional :new_line, type: Integer, desc: 'Line number after change'
            optional :old_path, type: String, desc: 'File path before change'
            optional :old_line, type: Integer, desc: 'Line number before change'
            optional :width, type: Integer, desc: 'Width of the image'
            optional :height, type: Integer, desc: 'Height of the image'
            optional :x, type: Integer, desc: 'X coordinate in the image'
            optional :y, type: Integer, desc: 'Y coordinate in the image'
          end
        end
        post ":id/#{noteables_path}/:noteable_id/discussions" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])
          type = params[:position] ? 'DiffNote' : 'DiscussionNote'
          id_key = noteable.is_a?(Commit) ? :commit_id : :noteable_id

          opts = {
            note: params[:body],
            created_at: params[:created_at],
            type: type,
            noteable_type: noteables_str.classify,
            position: params[:position],
            id_key => noteable.id
          }

          note = create_note(noteable, opts)

          if note.valid?
            present note.discussion, with: Entities::Discussion
          else
            bad_request!("Note #{note.errors.messages}")
          end
        end

        desc "Get comments in a single #{noteable_type.to_s.downcase} discussion" do
          success Entities::Discussion
        end
        params do
          requires :discussion_id, type: String, desc: 'The ID of a discussion'
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
        end
        get ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id/notes" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])
          notes = readable_discussion_notes(noteable, params[:discussion_id])

          if notes.empty?
            break not_found!("Notes")
          end

          present notes, with: Entities::Note
        end

        desc "Add a comment to a #{noteable_type.to_s.downcase} discussion" do
          success Entities::Note
        end
        params do
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
          requires :discussion_id, type: String, desc: 'The ID of a discussion'
          requires :body, type: String, desc: 'The content of a note'
          optional :created_at, type: String, desc: 'The creation date of the note'
        end
        post ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id/notes" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])
          notes = readable_discussion_notes(noteable, params[:discussion_id])

          break not_found!("Discussion") if notes.empty?
          break bad_request!("Discussion is an individual note.") unless notes.first.part_of_discussion?

          opts = {
            note: params[:body],
            type: 'DiscussionNote',
            in_reply_to_discussion_id: params[:discussion_id],
            created_at: params[:created_at]
          }
          note = create_note(noteable, opts)

          if note.valid?
            present note, with: Entities::Note
          else
            bad_request!("Note #{note.errors.messages}")
          end
        end

        desc "Get a comment in a #{noteable_type.to_s.downcase} discussion" do
          success Entities::Note
        end
        params do
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
          requires :discussion_id, type: String, desc: 'The ID of a discussion'
          requires :note_id, type: Integer, desc: 'The ID of a note'
        end
        get ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id/notes/:note_id" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])

          get_note(noteable, params[:note_id])
        end

        desc "Edit a comment in a #{noteable_type.to_s.downcase} discussion" do
          success Entities::Note
        end
        params do
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
          requires :discussion_id, type: String, desc: 'The ID of a discussion'
          requires :note_id, type: Integer, desc: 'The ID of a note'
          optional :body, type: String, desc: 'The content of a note'
          optional :resolved, type: Boolean, desc: 'Mark note resolved/unresolved'
          exactly_one_of :body, :resolved
        end
        put ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id/notes/:note_id" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])

          if params[:resolved].nil?
            update_note(noteable, params[:note_id])
          else
            resolve_note(noteable, params[:note_id], params[:resolved])
          end
        end

        desc "Delete a comment in a #{noteable_type.to_s.downcase} discussion" do
          success Entities::Note
        end
        params do
          requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
          requires :discussion_id, type: String, desc: 'The ID of a discussion'
          requires :note_id, type: Integer, desc: 'The ID of a note'
        end
        delete ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id/notes/:note_id" do
          noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])

          delete_note(noteable, params[:note_id])
        end

        if Noteable::RESOLVABLE_TYPES.include?(noteable_type.to_s)
          desc "Resolve/unresolve an existing #{noteable_type.to_s.downcase} discussion" do
            success Entities::Discussion
          end
          params do
            requires :noteable_id, types: [Integer, String], desc: 'The ID of the noteable'
            requires :discussion_id, type: String, desc: 'The ID of a discussion'
            requires :resolved, type: Boolean, desc: 'Mark discussion resolved/unresolved'
          end
          put ":id/#{noteables_path}/:noteable_id/discussions/:discussion_id" do
            noteable = find_noteable(parent_type, noteables_str, params[:noteable_id])

            resolve_discussion(noteable, params[:discussion_id], params[:resolved])
          end
        end
      end
    end

    helpers do
      def readable_discussion_notes(noteable, discussion_id)
        notes = noteable.notes
          .where(discussion_id: discussion_id)
          .inc_relations_for_view
          .includes(:noteable)
          .fresh

        notes.reject { |n| n.cross_reference_not_visible_for?(current_user) }
      end
    end
  end
end
