# R overlay -- overlay package, ebuild header
# -*- coding: utf-8 -*-
# Copyright (C) 2012 André Erdmann <dywi@mailerd.de>
# Distributed under the terms of the GNU General Public License;
# either version 2 of the License, or (at your option) any later version.

"""ebuild header

This module provides one class, EbuildHeader, that is used to create ebuild
headers ("copyright..., inherit...").
"""

class EbuildHeader ( object ):
   def __init__ ( self, default_header, eapi ):
      self.default_header = default_header
      self.eapi_str       = 'EAPI=' + str ( eapi ) + '\n'
      self.eclasses       = None

      self._cached_header = None
   # --- end of __init__ (...) ---

   def set_eclasses ( self, eclass_names ):
      self.eclasses = eclass_names
   # --- end of set_eclasses (...) ---

   def get ( self, use_cached=True ):
      if self._cached_header is None or not use_cached:
         self._cached_header = self._make()
      return self._cached_header
   # --- end of get (...) ---

   def get_use_expand_header ( self, use_expand_name ):
      if self.default_header:
         return (
            self.default_header + '\n'
            + (
               '# This file contains descriptions of the {} '
               'USE_EXPAND flags.'.format ( use_expand_name )
            ) + '\n'
         )
      else:
         return None
   # --- end of get_use_expand_header (...) ---

   def _make ( self ):
      if self.eclasses:
         inherit = 'inherit ' + ' '.join ( sorted ( self.eclasses ) )
      else:
         inherit = None

      # header and inherit is expected and therefore the first condition here
      if inherit and self.default_header:
         return (
            self.default_header + '\n' + self.eapi_str + '\n' + inherit
         )

      elif inherit:
         return self.eapi_str + '\n' + inherit

      elif self.default_header:
         return self.default_header + '\n' + self.eapi_str

      else:
         return self.eapi_str
   # --- end of _make (...) ---