#--
#++

#require 'digest/md5'

module Reap

  # = Filer
  #
  #

  class Filer

    include TaskUtils

    attr_accessor :source

    def initialize( name, source, &build )
      @name   = name
      @source = [source].flatten
      @build  = build
    end

    # Is this file task needed?  Yes if it doesn't exist, or if its time
    # stamp is out of date.
    def needed?
      return true unless ::File.exist?( @name )
      return true if out_of_date?( timestamp( @name ) )
      false
    end

    # Check timestamp.
    def timestamp( name )
      if ::File.exist?( name.to_s )
        ::File.mtime( name.to_s )
      else
        Time::EARLY  # TODO replace with Facets' -Infinity class (?)
      end
    end

    # Are there any sources with a later time than the given timestamp?
    def out_of_date?( stamp )
      @source.any? { |n| timestamp(n) > stamp }
    end

    # Build file.

    def build
      @build.call if needed?
    end

    alias_method :call, :build

  private

    #def salt( file )
    #  Digest::MD5.new( File.read( file ) ).hexdigest
    #end

  end

end #module Reap