# Author::    Eric Crane  (mailto:eric.crane@mac.com)
# Copyright:: Copyright (c) 2019 Eric Crane.  All rights reserved.
#
# An object that points to a file in the system.
#

module Gloo
  module Objs
    class FileHandle < Gloo::Core::Obj

      KEYWORD = 'file'.freeze
      KEYWORD_SHORT = 'dir'.freeze

      #
      # The name of the object type.
      #
      def self.typename
        return KEYWORD
      end

      #
      # The short name of the object type.
      #
      def self.short_typename
        return KEYWORD_SHORT
      end

      # ---------------------------------------------------------------------
      #    Messages
      # ---------------------------------------------------------------------

      #
      # Get a list of message names that this object receives.
      #
      def self.messages
        return super + %w[read write check_exists check_is_file check_is_dir]
      end

      def msg_read
        return unless value && File.file?( value )

        data = File.read( value )
        if @params&.token_count&.positive?
          pn = Gloo::Core::Pn.new @params.first
          o = pn.resolve
          o.set_value data
        else
          $engine.heap.it.set_to data
        end
      end

      def msg_write
        data = ''
        return unless value

        if @params&.token_count&.positive?
          expr = Gloo::Expr::Expression.new( @params.tokens )
          data = expr.evaluate
        end
        File.write( value, data )
      end

      # Check to see if the file exists.
      def msg_check_exists
        result = File.exist? value
        $engine.heap.it.set_to result
      end

      # Check to see if the file is a file.
      def msg_check_is_file
        result = File.file? value
        $engine.heap.it.set_to result
      end

      # Check to see if the file is a directory.
      def msg_check_is_dir
        result = File.directory? value
        $engine.heap.it.set_to result
      end

      # ---------------------------------------------------------------------
      #    Help
      # ---------------------------------------------------------------------

      #
      # Get help for this object type.
      #
      def self.help
        return <<~TEXT
          FILE OBJECT TYPE
            NAME: file
            SHORTCUT: dir

          DESCRIPTION
            Reference to a file or folder (directory) on disk.
            The string value of the file object is the path and name
            of the file.

          CHILDREN
            None.

          MESSAGES
            read <into.obj> - Read file and put data in the specified object.
              If the <into.obj> is not specified, the data will be in <it>.
            write <from.obj> - Write the data in the <from.object> into
              the file.
            check_exists - Check to see if the file exists.
              <It> will be true or false.
            check_is_file - Check to see if the file specified is a
              regular file.  <It> will be true or false.
            check_is_dir - Check to see if the file specified is a
              diretory.  <It> will be true or false.
        TEXT
      end

    end
  end
end