# -*- coding: UTF-8 -*-

# Copyright (c) 2007 - 2010, Pascal Volk

# See COPYING for distribution information.

"""

    VirtualMailManager.Config

    VMM's configuration module for simplified configuration access.

"""

from ConfigParser import \

     Error, MissingSectionHeaderError, NoOptionError, NoSectionError, \

     ParsingError, RawConfigParser

from cStringIO import StringIO# TODO: move interactive stff to cli

from VirtualMailManager import exec_ok, get_unicode, is_dir

from VirtualMailManager.constants.ERROR import CONF_ERROR

from VirtualMailManager.Exceptions import VMMConfigException

class BadOptionError(Error):

    """Raised when a option isn't in the format 'section.option'."""

    pass

class ConfigValueError(Error):

    """Raised when creating or validating of new values fails."""

    pass

class NoDefaultError(Error):

    """Raised when the requested option has no default value."""

    def __init__(self, section, option):

        Error.__init__(self, 'Option %r in section %r has no default value' %

                             (option, section))

class LazyConfig(RawConfigParser):

    """The **lazy** derivate of the `RawConfigParser`.

    There are two additional getters:

    `pget()`

      The polymorphic getter, which returns a option's value with the

      appropriate type.

    `dget()`

      Like `LazyConfig.pget()`, but returns the option's default, from

      `LazyConfig._cfg['sectionname']['optionname'].default`, if the

      option is not configured in a ini-like configuration file.

    """

    def __init__(self):

        RawConfigParser.__init__(self)

        self._modified = False

        self._cfg = {

            'sectionname': {

            }

        }

    def bool_new(self, value):

        """Converts the string `value` into a `bool` and returns it.

        | '1', 'on', 'yes' and 'true' will become `True`

        | '0', 'off', 'no' and 'false' will become `False`

        Throws a `ConfigValueError` for all other values, except bools.

        """

        if isinstance(value, bool):

            return value

        if value.lower() in self._boolean_states:

            return self._boolean_states[value.lower()]

        else:

            raise ConfigValueError(_(u"Not a boolean: '%s'") %

                                   get_unicode(value))

    def getboolean(self, section, option):

        For a boolean True, the value must be set to '1', 'on', 'yes',

        'true' or True. For a boolean False, the value must set to '0',

        'off', 'no', 'false' or False.

        """

        # if the setting was modified it may be still a boolean value lets see

        tmp = self.get(section, option)

        if isinstance(tmp, bool):

            return tmp

        if not tmp.lower() in self._boolean_states:

        return self._boolean_states[tmp.lower()]

    def _get_section_option(self, section_option):

        Else one of the following exceptions will be thrown:

        """

        sect_opt = section_option.lower().split('.')

        # TODO: cache it

        if len(sect_opt) != 2:# do we need a regexp to check the format?

            raise BadOptionError(

                        _(u"Bad format: '%s' - expected: section.option") %

                                 get_unicode(section_option))

        if not sect_opt[0] in self._cfg:

            raise NoSectionError(sect_opt[0])

        if not sect_opt[1] in self._cfg[sect_opt[0]]:

            raise NoOptionError(sect_opt[1], sect_opt[0])

        return sect_opt

    def items(self, section):

        if section in self._sections:# check if the section was parsed

        elif not section in self._cfg:

            raise NoSectionError(section)

        else:

            return ((k, self._cfg[section][k].default) \

                    for k in self._cfg[section].iterkeys())

        # still here? Get defaults and merge defaults with configured setting

    def dget(self, option):

        """Returns the value of the `option`.

        If the option could not be found in the configuration file, the

        configured default value, from ``LazyConfig._cfg`` will be

        returned.

        Arguments:

        `option` : string

        Throws a `NoDefaultError`, if no default value was passed to

        `LazyConfigOption.__init__()` for the `option`.

        """

        section, option = self._get_section_option(option)

        try:

            return self._cfg[section][option].getter(section, option)

        except (NoSectionError, NoOptionError):

            if not self._cfg[section][option].default is None:# may be False

                return self._cfg[section][option].default

            else:

                raise NoDefaultError(section, option)

    def pget(self, option):

        """Returns the value of the `option`."""

        section, option = self._get_section_option(option)

        return self._cfg[section][option].getter(section, option)

    def set(self, option, value):

        """Set the `value` of the `option`.

        Throws a `ValueError` if `value` couldn't be converted using

        section, option = self._get_section_option(option)

        val = self._cfg[section][option].cls(value)

        if self._cfg[section][option].validate:

            val = self._cfg[section][option].validate(val)

        if not RawConfigParser.has_section(self, section):

            self.add_section(section)

        RawConfigParser.set(self, section, option, val)

        self._modified = True

    def has_section(self, section):

        """Checks if `section` is a known configuration section."""

        return section.lower() in self._cfg

    def has_option(self, option):

        try:

            self._get_section_option(option)

            return True

        except(BadOptionError, NoSectionError, NoOptionError):

            return False

    def sections(self):

        """Returns an iterator object for all configuration sections."""

        return self._cfg.iterkeys()

class LazyConfigOption(object):

    """A simple container class for configuration settings.

    `LazyConfigOption` instances are required by `LazyConfig` instances,

    and instances of classes derived from `LazyConfig`, like the

    `Config` class.

    """

    __slots__ = ('__cls', '__default', '__getter', '__validate')

    def __init__(self, cls, default, getter, validate=None):

        """Creates a new `LazyConfigOption` instance.

        Arguments:

        `cls` : type

          The class/type of the option's value

        `default`

        `getter` : callable

        `validate` : NoneType or a callable

        """

        self.__cls = cls

        if not default is None:# enforce the type of the default value

            self.__default = self.__cls(default)

        else:

            self.__default = default

        if not callable(getter):

            raise TypeError('getter has to be a callable, got a %r' %

                            getter.__class__.__name__)

        self.__getter = getter

        if validate and not callable(validate):

            raise TypeError('validate has to be callable or None, got a %r' %

                            validate.__class__.__name__)

        self.__validate = validate

    @property

    def cls(self):

        return self.__cls

    @property

    def default(self):

        """The option's default value, may be `None`"""

        return self.__default

    @property

    def getter(self):

        """The getter method or function to get the option's value"""

        return self.__getter

    @property

    def validate(self):

        """A method or function to validate the value"""

        return self.__validate

class Config(LazyConfig):

    """This class is for reading vmm's configuration file."""

    def __init__(self, filename):

        """Creates a new Config instance

        Arguments:

        `filename` : str

          path to the configuration file

        """

        LazyConfig.__init__(self)

        self.__missing = {}

        LCO = LazyConfigOption

        bool_t = self.bool_new

        self._cfg = {

            'account': {

                'delete_directory': LCO(bool_t, False, self.getboolean),

            },

            'bin': {

            },

            'database': {

                'host': LCO(str, 'localhost', self.get),

            },

            'domain': {

                'delete_directory': LCO(bool_t, False, self.getboolean),

            },

            'maildir': {

                'folders': LCO(str, 'Drafts:Sent:Templates:Trash', self.get),

            },

            'misc': {

                                       self.known_scheme),

            },

        }

    def load(self):

        """Loads the configuration, read only.

        """

        try:

        finally:

    def check(self):

        """Performs a configuration check.

        Raises a VMMConfigException if the check fails.

        """

        # TODO: There are only two settings w/o defaults.

        #       So there is no need for cStringIO

            errmsg = StringIO()

            errmsg.write(_(u'Missing options, which have no default value.\n'))

            errmsg.write(_(u'Using configuration file: %s\n') %

            for section, options in self.__missing.iteritems():

                errmsg.write(_(u'* Section: %s\n') % section)

                for option in options:

                    errmsg.write((u'    %s\n') % option)

            raise VMMConfigException(errmsg.getvalue(), CONF_ERROR)

    def known_scheme(self, scheme):

        """Converts `scheme` to upper case and checks if is known by

        Dovecot (listed in VirtualMailManager.SCHEMES).