require 'fs/ReiserFS/utils'

module ReiserFS
  class DirectoryEntry
    ITEM_STAT_V1 = BinaryStruct.new([
      'v',  'mode',
      'v',  'nlinks',
      'v',  'uid',
      'v',  'gid',
      'V',  'size',
      'V',  'atime',
      'V',  'mtime',
      'V',  'ctime',
      'V',  'nblocks',
      'V',  'first'
    ])
    SIZEOF_ITEM_STAT_V1 = ITEM_STAT_V1.size

    ITEM_STAT_V2 = BinaryStruct.new([
      'v',  'mode',
      'a2', 'reserved',
      'V',  'nlinks',
      'Q',  'size',
      'V',  'uid',
      'V',  'gid',
      'V',  'atime',
      'V',  'mtime',
      'V',  'ctime',
      'V',  'nblocks',
      'V',  'first'
    ])
    SIZEOF_ITEM_STAT_V2 = ITEM_STAT_V2.size

    # Bits 0 to 8 of file mode.
    PF_O_EXECUTE  = 0x0001  # owner execute
    PF_O_WRITE    = 0x0002  # owner write
    PF_O_READ     = 0x0004  # owner read
    PF_G_EXECUTE  = 0x0008  # group execute
    PF_G_WRITE    = 0x0010  # group write
    PF_G_READ     = 0x0020  # group read
    PF_U_EXECUTE  = 0x0040  # user execute
    PF_U_WRITE    = 0x0080  # user write
    PF_U_READ     = 0x0100  # user read

    # For accessor convenience.
    MSK_PERM_OWNER = (PF_O_EXECUTE | PF_O_WRITE | PF_O_READ)
    MSK_PERM_GROUP = (PF_G_EXECUTE | PF_G_WRITE | PF_G_READ)
    MSK_PERM_USER  = (PF_U_EXECUTE | PF_U_WRITE | PF_U_READ)

    # Bits 9 to 11 of file mode.
    DF_STICKY     = 0x0200
    DF_SET_GID    = 0x0400
    DF_SET_UID    = 0x0800

    # Bits 12 to 15 of file mode.
    FM_FIFO       = 0x1000  # fifo device (pipe)
    FM_CHAR       = 0x2000  # char device
    FM_DIRECTORY  = 0x4000  # directory
    FM_BLOCK_DEV  = 0x6000  # block device
    FM_FILE       = 0x8000  # regular file
    FM_SYM_LNK    = 0xa000  # symbolic link
    FM_SOCKET     = 0xc000  # socket device

    # For accessor convenience.
    MSK_FILE_MODE = 0xf000
    MSK_IS_DEV    = (FM_FIFO | FM_CHAR | FM_BLOCK_DEV | FM_SOCKET)

    attr_reader :key, :blockObj

    def initialize(blockObj, itemHeader, key)
      @itemHeader = itemHeader
      @blockObj   = blockObj
      @key        = key
      @data       = @blockObj.getItem(itemHeader)
      @version    = @blockObj.getItemVersion(itemHeader)

      statStruct = @version == 0 ? ITEM_STAT_V1 : ITEM_STAT_V2
      statSize   = @version == 0 ? SIZEOF_ITEM_STAT_V1 : SIZEOF_ITEM_STAT_V2
      raise "Stat Structure Length Inconsistency" if statSize != @data.length
      @stat = statStruct.decode(@data)
      @mode = @stat['mode']
    end

    def isDir?
      @mode & FM_DIRECTORY == FM_DIRECTORY
    end

    def isFile?
      @mode & FM_FILE == FM_FILE
    end

    def isDev?
      @mode & MSK_IS_DEV > 0
    end

    def isSymLink?
      @mode & FM_SYM_LNK == FM_SYM_LNK
    end

    def permissions
      @mode & (MSK_PERM_OWNER | MSK_PERM_GROUP | MSK_PERM_USER)
    end

    def ownerPermissions
      @mode & MSK_PERM_OWNER
    end

    def groupPermissions
      @mode & MSK_PERM_GROUP
    end

    def userPermissions
      @mode & MSK_PERM_USER
    end

    def uid
      @stat['uid']
    end

    def gid
      @stat['gid']
    end

    def aTime
      Time.at(@stat['atime'])
    end

    def cTime
      Time.at(@stat['ctime'])
    end

    def mTime
      Time.at(@stat['mtime'])
    end

    def length
      @stat['size']
    end
  end
end