#
# @author: Adam Kubica (caffecoder) <caffecoder@kaizen-step.com>
#

#
# Class for manage hashed file distribution.
#
class FileDistribution

  # Creates new instance with directory prefix.
  #
  # Params:
  # - prefix: directory prefix.
  def initialize(prefix)
    @ext = '.dat'
    @prefix = File.expand_path(prefix)
    @path = @prefix
  end

  # Params:
  # - ext: file extension.
  def set_extension(ext)
    if ext.length > 0 && ext.chars.first != '.'
      @ext = '.' + ext
    else
      @ext = ext
    end
  end

  # Returns Destination path.
  def get_path
    @path
  end

  # Params:
  # - id: database file ID etc.
  def hex_path(id)
    hex = "%x" % id
    hex = '0%s' % hex if hex.length % 2 != 0
    @path = File.join(@prefix,hex.scan(/../))
    @path += @ext
  end

  # Params:
  # - path: source file path.
  #
  # Raises a SystemCallError if the file cannot be renamed.
  def rename_from(path)
    dst_dir = File.dirname(@path)
    FileUtils.mkpath(dst_dir) unless File.exists?(dst_dir)

    File.rename(path,@path)
  end
end