from twisted.internet import defer
from inspect import getcallargs
from decorator import decorator

from .schema import User
from .dbdefer import dbdefer

from ..validate import validate, vHash
from ..error import UserNotFound, InterfaceException


@validate(kwd="apikey", func=vHash, minlength=15, maxlength=15)
@dbdefer
def getuser(session, apikey):
    """Returns a valid user object.

    :param session: a valid session object (is created by decorator :func:`iro.model.dbdefer.dbdefer`)
    :param string apikey: a vaild apikey (only [0-9a-f] is allowed)
    :return: a :class:`iro.model.schema.User` object
    :raises: :exc:`iro.error.UserNotFound`
    """
    user = session.query(User).filter_by(apikey=apikey).first()
    if user is None:
        raise UserNotFound()
    else:
        return user

@decorator
def vUser(f,*args,**kargs):
    """A Decorator to verify the apikey and execute the function with a valid :class:`iro.model.schema.User` instead of the apikey.
    
    The decorator expect the apikey in the **user** parameter.

    :return: a defer
    """ 
    kp=getcallargs(f,*args,**kargs)
    try:
        apikey = kp["user"]
    except KeyError:
        raise InterfaceException() 
    
    def _gotResult(_user):
        kp["user"]=_user
        e =  defer.maybeDeferred(f,**kp)
        return e
    d = defer.maybeDeferred(getuser, apikey=apikey)
    return d.addCallback(_gotResult)