radar/twist-v2

module Twist
  module Web
    module GraphQL
      class Runner
        def initialize(repos:)
          @repos = repos
        end

        # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
        def run(query:, variables: {}, context: {})
          context = context.merge(
            branch_loader: branch_loader,
            commit_loader: commit_loader,
            element_loader: element_loader,
            image_loader: image_loader,
            note_count_loader: note_count_loader,
            user_loader: user_loader,
            book_repo: repo(:book),
            branch_repo: repo(:branch),
            chapter_repo: repo(:chapter),
            comment_repo: repo(:comment),
            commit_repo: repo(:commit),
            book_note_repo: repo(:book_note),
            element_repo: repo(:element),
            footnote_repo: repo(:footnote),
            image_repo: repo(:image),
            permission_repo: repo(:permission),
            note_repo: repo(:note),
            user_repo: repo(:user),
            reader_repo: repo(:reader),
          )

          context[:current_user] = repo(:user).first if ENV['BYPASS_PERMISSIONS']

          Web::GraphQL::Schema.execute(
            query,
            variables: variables,
            context: context,
          )
        end
        # rubocop:enable Metrics/MethodLength, Metrics/AbcSize

        private

        attr_reader :repos

        def repo(name)
          repos[name] || Repositories::NullRepo.new(name)
        end

        def branch_loader
          Dataloader.new do |ids|
            ids.empty? ? [] : repo(:branch).by_ids(ids)
          end
        end

        def commit_loader
          Dataloader.new do |ids|
            ids.empty? ? [] : repo(:commit).by_ids(ids)
          end
        end

        def element_loader
          Dataloader.new do |ids|
            ids.empty? ? [] : repo(:element).by_ids(ids)
          end
        end

        def image_loader
          Dataloader.new do |ids|
            ids.empty? ? [] : repo(:image).by_ids(ids)
          end
        end

        def note_count_loader
          Dataloader.new do |element_ids|
            element_ids.empty? ? [] : repo(:note).count(element_ids, "open")
          end
        end

        def user_loader
          Dataloader.new do |ids|
            ids.empty? ? [] : repo(:user).by_ids(ids).map { |user| [user.id, user] }.to_h
          end
        end
      end
    end
  end
end