# encoding: utf-8

class Vulcano::Plugins::Backend
  class FileCommon
    # interface methods: these fields should be implemented by every
    # backend File
    %w{
      exists? mode owner group link_target content mtime size
      selinux_label product_version file_version
    }.each do |m|
      define_method m.to_sym do
        fail NotImplementedError.new("File must implement the #{m}() method.")
      end
    end

    def type
      :unknown
    end

    # The following methods can be overwritten by a derived class
    # if desired, to e.g. achieve optimizations.

    def md5sum
      res = Digest::MD5.new
      res.update(content)
      res.hexdigest
    end

    def sha256sum
      res = Digest::SHA256.new
      res.update(content)
      res.hexdigest
    end

    # Additional methods for convenience

    def file?
      type == :file
    end

    def block_device?
      type == :block_device
    end

    def character_device?
      type == :character_device
    end

    def socket?
      type == :socket
    end

    def directory?
      type == :directory
    end

    def symlink?
      type == :symlink
    end

    def pipe?
      type == :pipe?
    end

    def mode?(mode)
      mode == mode
    end

    def owned_by?(owner)
      owner == owner
    end

    def grouped_into?(group)
      group == group
    end

    def linked_to?(dst)
      link_target == dst
    end

    def version?(version)
      product_version == version or
      file_version == version
    end

    # helper methods provided to any implementing class

    private

    UNIX_MODE_OWNERS = {
      owner: 00700,
      group: 00070,
      other: 00007
    }

    UNIX_MODE_TYPES = {
      r: 00444,
      w: 00222,
      x: 00111
    }

    def unix_mode_mask(owner, type)
      o = UNIX_MODE_OWNERS[owner.to_sym]
      return nil if o.nil?

      t = UNIX_MODE_TYPES[type.to_sym]
      return nil if t.nil?

      t & o
    end
  end
end