paulfioravanti/resume

require "optparse"
require_relative "exceptions"

module Resume
  module CLI
    # CLI argument validity parser.
    #
    # @author Paul Fioravanti
    module ArgumentParser
      module_function

      # Parses the CLI arguments.
      #
      # @raise [InvalidOptionError]
      #   if a CLI option is invalid (eg invalid locale)
      # @raise [MissingArgumentError]
      #   if a CLI option is missing (eg -l flag without locale)
      # @raise [LocaleNotSupportedError]
      #   if the given locale is not supported by the app.
      # @return [Array]
      #   if all arguments can be parsed correctly, an empty array will
      #   be returned.
      def parse
        help = parser.help
        parser.parse!(ARGV)
      rescue OptionParser::InvalidOption
        raise InvalidOptionError, help
      rescue OptionParser::MissingArgument
        raise MissingArgumentError, help
      end

      def parser
        OptionParser.new do |opts|
          opts.banner = "Usage: ./bin/resume [options]"
          opts.separator("")
          opts.separator "Specific options:"
          locale_option(opts)
          opts.separator("")
          opts.separator "Common options:"
          help_option(opts)
          version_option(opts)
        end
      end
      private_class_method :parser

      def locale_option(opts)
        opts.on(
          "-l",
          "--locale LOCALE",
          "Select the locale of the resume " \
          "(#{I18n.available_locales.join(', ')})"
        ) do |locale|
          I18n.locale = locale.to_sym
        rescue I18n::InvalidLocale
          raise LocaleNotSupportedError, locale
        end
      end
      private_class_method :locale_option

      def help_option(opts)
        opts.on_tail("-h", "--help", "Show this message") do
          Output.raw(opts)
          throw :halt
        end
      end
      private_class_method :help_option

      def version_option(opts)
        opts.on_tail("-v", "--version", "Show version") do
          Output.raw(Resume::VERSION)
          throw :halt
        end
      end
      private_class_method :version_option
    end
  end
end