version_checker.rb

require_relative "version"

module ReactOnRails
  class VersionChecker
    attr_reader :node_package_version, :logger

    def self.build
      new(NodePackageVersion.build, Rails.logger)
    end

    def initialize(node_package_version, logger)
      @logger = logger
      @node_package_version = node_package_version
    end

    # For compatibility, the gem and the node package versions should always match, unless the user
    # really knows what they're doing. So we will give a warning if they do not.
    def warn_if_gem_and_node_package_versions_differ
      return if node_package_version.major == gem_major_version || node_package_version.relative_path?
      log_differing_versions_warning
    end

    private

    def log_differing_versions_warning
      msg = "**WARNING** ReactOnRails: ReactOnRails gem and node package major versions do not match\n" \
            "                     gem: #{gem_version}\n" \
            "            node package: #{node_package_version.raw}\n" \
            "Ensure the installed version of the gem is the same as the version of your installed node package"
      logger.warn(msg)
    end

    def gem_version
      ReactOnRails::VERSION
    end

    def gem_major_version
      gem_version.match(/(\d+)\..*/)[1]
    end
  end

  class NodePackageVersion
    attr_reader :package_json

    def self.build
      new(package_json_path)
    end

    def self.package_json_path
      Rails.root.join("client", "package.json")
    end

    def initialize(package_json)
      @package_json = package_json
    end

    def raw
      JSON.parse(package_json_contents)["dependencies"]["react-on-rails"]
    end

    def normalized
      match = raw
              .tr("-", ".")
              .strip
              .match(/(\d.*)/)
      match.present? ? match[0] : nil
    end

    def relative_path?
      normalized.nil? # must be a relative path if nil and we haven't failed
    end

    def major
      return if normalized.nil?
      normalized.match(/(\d+)\..*/)[1]
    end

    private

    def package_json_contents
      @package_json_contents ||= File.read(package_json)
    end
  end
end