# frozen_string_literal: true

module Packages
  module Npm
    class PackagePresenter
      include API::Helpers::RelatedResourcesHelpers

      attr_reader :name, :packages

      NPM_VALID_DEPENDENCY_TYPES = %i[dependencies devDependencies bundleDependencies peerDependencies].freeze

      def initialize(name, packages)
        @name = name
        @packages = packages
      end

      def versions
        package_versions = {}

        packages.each do |package|
          package_file = package.package_files.last

          next unless package_file

          package_versions[package.version] = build_package_version(package, package_file)
        end

        package_versions
      end

      def dist_tags
        build_package_tags.tap { |t| t["latest"] ||= sorted_versions.last }
      end

      private

      def build_package_tags
        Hash[
          package_tags.map { |tag| [tag.name, tag.package.version] }
        ]
      end

      def build_package_version(package, package_file)
        {
          name: package.name,
          version: package.version,
          dist: {
            shasum: package_file.file_sha1,
            tarball: tarball_url(package, package_file)
          }
        }.tap do |package_version|
          package_version.merge!(build_package_dependencies(package))
        end
      end

      def tarball_url(package, package_file)
        expose_url "#{api_v4_projects_path(id: package.project_id)}" \
          "/packages/npm/#{package.name}" \
          "/-/#{package_file.file_name}"
      end

      def build_package_dependencies(package)
        dependencies = Hash.new { |h, key| h[key] = {} }
        dependency_links = package.dependency_links
                                  .with_dependency_type(NPM_VALID_DEPENDENCY_TYPES)
                                  .includes_dependency

        dependency_links.find_each do |dependency_link|
          dependency = dependency_link.dependency
          dependencies[dependency_link.dependency_type][dependency.name] = dependency.version_pattern
        end

        dependencies
      end

      def sorted_versions
        versions = packages.map(&:version).compact
        VersionSorter.sort(versions)
      end

      def package_tags
        Packages::Tag.for_packages(packages)
                    .preload_package
      end
    end
  end
end