from functools import partial

try:

    from collections import OrderedDict

except ImportError:

    from ordereddict import OrderedDict

from ..error import NoRoute, NoTyp, ValidateException, NoProvider

from ..config import Option, Config

class Provider(Config):

    """Base class for Providerbackends."""

    testmode = False

    """- **True** -- no message to external provider should be send.

    - **False** (default) -- message are send to external provider."""

    def __init__(self, name, typs={}, options=[]):

        """Constructor for Provider class.

        :param string name: Name of the Provider.

        :param dict typs: A Dictonary with typs and routes.

        :param items options: [("name",Option(...)),...]

        >>> p = Provider("myProvider",{"sms":["route1","route2"]})

        """

        Config.__init__(self, name, OrderedDict([

                    ("typ",Option(vProvider, long="One available provider typ.", must=True, default=name))

                    ]+options)

                )

        self.typs=typs

        self.testmode = False

    def send(self, typ, route, recipient, message):

        """Main send function, that is called, for every single message.

        .. note::

            This function is not used directly. Normally :func:`~iro.offer.provider.Provider.getSendFunc` return this function with typ and route bound."""

        pass

    def getSendFunc(self, typ, route):

        """Returns the actually send function for a given typ and route.

        Normally it returns the send function with typ and route bound.

        :raises: :exc:`~iro.error.NoRoute`, :exc:`~iro.error.NoTyp`

        """

        try:

            if route not in self.typs[typ]:

                raise NoRoute(route)

        except KeyError:

            raise NoTyp(route)

        return partial(self.send, typ, route)

def getProvider(name, typ, config):

    '''creates a provider object and init this with config.

    :param dict config: The Configuration dict. Normally you use ``configParser.items("section")``.

    :param string typ: A valid typ

    :raises: :exc:`~iro.error.NoProvider`

    '''

    try:

        p = providers[typ](name)

        p.load(config)

        return p

    except KeyError:

        raise NoProvider(typ)

def vProvider(typ, field):

    '''validator to test the existence of the typ.

    :param string typ: A typ

    :param string field: A field name used for the Exception.

    :return:

        - valid -- returns typ

        - invalid -- raises :class:`~iro.error.ValidateException`

    :raises: :exc:`~iro.error.ValidateException`

    '''

    if typ not in providers.keys():

        raise ValidateException(field=field)

    return typ

providers={}

"""Avalable Providers.

    - **key** -- typ of provider (see configuration typ field).

    - **value** -- class to handle specific Providertyp.

To extend provider typs, just add this new typ to this dict.

see :doc:`provider`

"""