# -*- coding: utf-8 -*-
from collections import UserDict
from configobj import ConfigObj, ParseError
from validate import Validator, VdtValueError
import os

class ConfigurationResetException(Exception):
 pass

class Configuration (UserDict):

	def __init__ (self, file=None, spec=None, *args, **kwargs):
		self.file = file
		self.spec = spec
		self.validator = Validator()
		self.setup_config(file=file, spec=spec)
		self.validated = self.config.validate(self.validator, copy=True)
		if self.validated:
			self.write()
		UserDict.__init__(self, self.config)

	def setup_config (self, file, spec):
		spec = ConfigObj(spec, list_values=False, encoding="utf-8")
		try:
			self.config = ConfigObj(infile=file, configspec=spec, create_empty=True, stringify=True, encoding="utf-8")
		except ParseError:
			os.remove(file)
			self.config = ConfigObj(infile=file, configspec=spec, create_empty=True, stringify=True)
			raise ConfigurationResetException

	def __getitem__ (self, *args, **kwargs):
		return dict(self.config).__getitem__(*args, **kwargs)

	def __setitem__ (self, *args, **kwargs):
		self.config.__setitem__(*args, **kwargs)
		UserDict.__setitem__(self, *args, **kwargs)

	def write (self):
		if hasattr(self.config, 'write'):
			self.config.write()

class SessionConfiguration (Configuration):
	def setup_config (self, file, spec):
		#No infile required.
		spec = ConfigObj(spec, list_values=False)
		self.config = ConfigObj(configspec=spec, stringify=True)