class Thor
  module Actions
    # Creates an empty directory.
    #
    # ==== Parameters
    # destination<String>:: the relative path to the destination root.
    # config<Hash>:: give :verbose => false to not log the status.
    #
    # ==== Examples
    #
    #   empty_directory "doc"
    #
    def empty_directory(destination, config = {})
      action EmptyDirectory.new(self, destination, config)
    end

    # Class which holds create directory logic. This is the base class for
    # other actions like create_file and directory.
    #
    # This implementation is based in Templater actions, created by Jonas Nicklas
    # and Michael S. Klishin under MIT LICENSE.
    #
    class EmptyDirectory #:nodoc:
      attr_reader :base, :destination, :given_destination, :relative_destination, :config

      # Initializes given the source and destination.
      #
      # ==== Parameters
      # base<Thor::Base>:: A Thor::Base instance
      # source<String>:: Relative path to the source of this file
      # destination<String>:: Relative path to the destination of this file
      # config<Hash>:: give :verbose => false to not log the status.
      #
      def initialize(base, destination, config = {})
        @base, @config   = base, {:verbose => true}.merge(config)
        self.destination = destination
      end

      # Checks if the destination file already exists.
      #
      # ==== Returns
      # Boolean:: true if the file exists, false otherwise.
      #
      def exists?
        ::File.exist?(destination)
      end

      def invoke!
        invoke_with_conflict_check do
          ::FileUtils.mkdir_p(destination)
        end
      end

      def revoke!
        say_status :remove, :red
        ::FileUtils.rm_rf(destination) if !pretend? && exists?
        given_destination
      end

    protected

      # Shortcut for pretend.
      #
      def pretend?
        base.options[:pretend]
      end

      # Sets the absolute destination value from a relative destination value.
      # It also stores the given and relative destination. Let's suppose our
      # script is being executed on "dest", it sets the destination root to
      # "dest". The destination, given_destination and relative_destination
      # are related in the following way:
      #
      #   inside "bar" do
      #     empty_directory "baz"
      #   end
      #
      #   destination          #=> dest/bar/baz
      #   relative_destination #=> bar/baz
      #   given_destination    #=> baz
      #
      def destination=(destination)
        if destination
          @given_destination = convert_encoded_instructions(destination.to_s)
          @destination = ::File.expand_path(@given_destination, base.destination_root)
          @relative_destination = base.relative_to_original_destination_root(@destination)
        end
      end

      # Filenames in the encoded form are converted. If you have a file:
      #
      #   %file_name%.rb
      #
      # It calls #file_name from the base and replaces %-string with the
      # return value (should be String) of #file_name:
      #
      #   user.rb
      #
      # The method referenced can be either public or private.
      #
      def convert_encoded_instructions(filename)
        filename.gsub(/%(.*?)%/) do |initial_string|
          method = $1.strip
          base.respond_to?(method, true) ? base.send(method) : initial_string
        end
      end

      # Receives a hash of options and just execute the block if some
      # conditions are met.
      #
      def invoke_with_conflict_check(&block)
        if exists?
          on_conflict_behavior(&block)
        else
          say_status :create, :green
          block.call unless pretend?
        end

        destination
      end

      # What to do when the destination file already exists.
      #
      def on_conflict_behavior(&block)
        say_status :exist, :blue
      end

      # Shortcut to say_status shell method.
      #
      def say_status(status, color)
        base.shell.say_status status, relative_destination, color if config[:verbose]
      end
    end
  end
end
