require 'rake/file_utils'

# ###########################################################################
# RakeFileUtils provides a custom version of the FileUtils methods that
# respond to the <tt>verbose</tt> and <tt>nowrite</tt> commands.
#
module RakeFileUtils
  include FileUtils

  class << self
    attr_accessor :verbose_flag, :nowrite_flag
  end
  RakeFileUtils.verbose_flag = :default
  RakeFileUtils.nowrite_flag = false

  $fileutils_verbose = true
  $fileutils_nowrite = false

  FileUtils::OPT_TABLE.each do |name, opts|
    default_options = []
    if opts.include?(:verbose) || opts.include?("verbose")
      default_options << ':verbose => RakeFileUtils.verbose_flag'
    end
    if opts.include?(:noop) || opts.include?("noop")
      default_options << ':noop => RakeFileUtils.nowrite_flag'
    end

    next if default_options.empty?
    module_eval(<<-EOS, __FILE__, __LINE__ + 1)
    def #{name}( *args, &block )
      super(
        *rake_merge_option(args,
          #{default_options.join(', ')}
          ), &block)
    end
    EOS
  end

  # Get/set the verbose flag controlling output from the FileUtils utilities.
  # If verbose is true, then the utility method is echoed to standard output.
  #
  # Examples:
  #    verbose              # return the current value of the verbose flag
  #    verbose(v)           # set the verbose flag to _v_.
  #    verbose(v) { code }  # Execute code with the verbose flag set temporarily to _v_.
  #                         # Return to the original value when code is done.
  def verbose(value=nil)
    oldvalue = RakeFileUtils.verbose_flag
    RakeFileUtils.verbose_flag = value unless value.nil?
    if block_given?
      begin
        yield
      ensure
        RakeFileUtils.verbose_flag = oldvalue
      end
    end
    RakeFileUtils.verbose_flag
  end

  # Get/set the nowrite flag controlling output from the FileUtils utilities.
  # If verbose is true, then the utility method is echoed to standard output.
  #
  # Examples:
  #    nowrite              # return the current value of the nowrite flag
  #    nowrite(v)           # set the nowrite flag to _v_.
  #    nowrite(v) { code }  # Execute code with the nowrite flag set temporarily to _v_.
  #                         # Return to the original value when code is done.
  def nowrite(value=nil)
    oldvalue = RakeFileUtils.nowrite_flag
    RakeFileUtils.nowrite_flag = value unless value.nil?
    if block_given?
      begin
        yield
      ensure
        RakeFileUtils.nowrite_flag = oldvalue
      end
    end
    oldvalue
  end

  # Use this function to prevent protentially destructive ruby code from
  # running when the :nowrite flag is set.
  #
  # Example:
  #
  #   when_writing("Building Project") do
  #     project.build
  #   end
  #
  # The following code will build the project under normal conditions. If the
  # nowrite(true) flag is set, then the example will print:
  #      DRYRUN: Building Project
  # instead of actually building the project.
  #
  def when_writing(msg=nil)
    if RakeFileUtils.nowrite_flag
      puts "DRYRUN: #{msg}" if msg
    else
      yield
    end
  end

  # Merge the given options with the default values.
  def rake_merge_option(args, defaults)
    if Hash === args.last
      defaults.update(args.last)
      args.pop
    end
    args.push defaults
    args
  end
  private :rake_merge_option

  # Send the message to the default rake output (which is $stderr).
  def rake_output_message(message)
    $stderr.puts(message)
  end
  private :rake_output_message

  # Check that the options do not contain options not listed in +optdecl+.  An
  # ArgumentError exception is thrown if non-declared options are found.
  def rake_check_options(options, *optdecl)
    h = options.dup
    optdecl.each do |name|
      h.delete name
    end
    raise ArgumentError, "no such option: #{h.keys.join(' ')}" unless h.empty?
  end
  private :rake_check_options

  extend self
end