'''This module implements a templating generator based on Cheetah'''
__revision__ = '$Revision$'

import Cheetah.Template, Cheetah.Parser
import logging, sys, traceback
import Bcfg2.Server.Plugin

logger = logging.getLogger('Bcfg2.Plugins.TCheetah')

class TemplateFile:
    '''Template file creates Cheetah template structures for the loaded file'''
    def __init__(self, name, properties, specific):
        self.name = name
        self.properties = properties
        self.specific = specific
        self.template = None
    
    def handle_event(self, event):
        '''Handle all fs events for this template'''
        if event.code2str() == 'deleted':
            return
        try:
            self.template = Cheetah.Template.Template(open(self.name).read())
            self.template.properties = self.properties.properties
        except Cheetah.Parser.ParseError, perror:
            logger.error("Cheetah parse error for file %s" % (self.name))
            logger.error(perror.report())
    
    def bind_entry(self, entry, metadata):
        '''Build literal file information'''
        self.template.metadata = metadata
        self.template.path = entry.get('realname', entry.get('name'))
        
        try:
            entry.text = str(self.template)
        except:
            (a, b, c) = sys.exc_info()
            msg = traceback.format_exception(a, b, c, limit=2)[-1][:-1]
            logger.error(msg)
            logger.error("TCheetah template error for %s" % self.template.path)
            del a, b, c
            raise Bcfg2.Server.Plugin.PluginExecutionError


class TCheetah(Bcfg2.Server.Plugin.GroupSpool):
    '''The TCheetah generator implements a templating mechanism for configuration files'''
    __name__ = 'TCheetah'
    __version__ = '$Id$'
    __author__ = 'bcfg-dev@mcs.anl.gov'
    filename_pattern = 'template'
    es_child_cls = TemplateFile
    use_props = True