require 'optparse'
require 'wright'

module Wright
  # Wright command-line interface.
  class CLI
    def initialize(main)
      @commands = []
      @requires = []
      @main = main
      set_up_parser
    end

    # Runs a wright script with the supplied arguments.
    #
    # @param argv [Array<String>] the arguments passed to bin/wright
    def run(argv)
      arguments = parse(argv)
      return if quit

      Wright.activate_dry_run if dry_run
      Wright.log.level = log_level if log_level
      main.extend Wright::DSL
      requires.each { |r| require r }

      run_script(arguments)
    end

    private

    attr_accessor :parser, :quit, :log_level, :dry_run
    attr_reader :commands, :requires, :main

    def parse(argv)
      # use OptionParser#order! instead of #parse! so CLI#run does not
      # consume --arguments passed to wright scripts
      parser.order!(argv)
    end

    def run_script(arguments)
      if commands.empty? && arguments.any?
        script = File.expand_path(arguments.shift)
        load script
      else
        cmds = commands.empty? ? $stdin.read : commands.join("\n")
        main.instance_eval(cmds, '<main>', 1)
      end
    end

    def set_up_parser
      self.parser = OptionParser.new
      set_up_command_option
      set_up_require_option
      set_up_dry_run_option
      set_up_verbosity_options
      set_up_version_option
    end

    def set_up_command_option
      parser.on('-e COMMAND', 'Run COMMAND') do |e|
        commands << e
      end
    end

    def set_up_require_option
      parser.on('-r LIBRARY',
                'Require LIBRARY before running the script') do |r|
        requires << r
      end
    end

    def set_up_dry_run_option
      parser.on('-n', '--dry-run', 'Enable dry-run mode') do
        self.dry_run = true
      end
    end

    def set_up_verbosity_options
      parser.on('-v', '--verbose', 'Increase verbosity') do
        self.log_level = Wright::Logger::DEBUG
      end

      parser.on('-q', '--quiet', 'Decrease verbosity') do
        self.log_level = Wright::Logger::ERROR
      end
    end

    def set_up_version_option
      parser.on_tail('--version', 'Show wright version') do
        puts "wright version #{Wright::VERSION}"
        self.quit = true
      end
    end
  end
end