require 'pathname'

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( /;/ ) )
          cmd = Pathname.new( cmd.to_s )

          return nil if cmd.to_s.empty?

          if cmd.absolute? 
            return cmd.to_s if cmd.executable?
            return nil
          end

          pathexts = [''] if pathexts.blank?

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