module FeduxOrg
  module Stdlib
    module Command
      module Which

        # Search for command
        # @param [String] cmd
        #    name of command or path to command (will be reduced to basename and then searched in PATH)
        #
        # @param [Array,String] paths
        #   a string containing paths separated by "File::PATH_SEPARATOR" or an array of paths
        #
        # @param [Array,String] pathexts
        #   a string containing pathexts separated by ";" or an array of pathexts
        #   
        # @return [String] 
        #   path to command
        def which(cmd, paths=ENV['PATH'].split(File::PATH_SEPARATOR), pathexts=ENV['PATHEXT'].to_s.split( /;/ ) )
          return nil if cmd.blank?

          cmd = File.basename( cmd )
          pathexts = [''] if pathexts.blank?

          Array( paths ).each do |path|
            Array( pathexts ).each do |ext|
              exe = File.join(path, "#{cmd}#{ext.to_s}")
              return exe if File.executable? exe
            end
          end                                                                                                                                                        
          nil
        end
      end
    end
  end
end