# -*- coding: utf-8 -*-
from openid.store.interface import OpenIDStore
from openid.association import Association as OIDAssociation
from openid.extensions import sreg
import openid.store

from django.db.models.query import Q
from django.conf import settings


# needed for some linux distributions like debian
try:
    from openid.yadis import xri
except:
    from yadis import xri

import time, base64, md5, operator

from models import Association, Nonce

__all__ = ['OpenID', 'DjangoOpenIDStore', 'from_openid_response']

class OpenID:
    def __init__(self, openid_, issued, attrs=None, sreg_=None):
        self.openid = openid_
        self.issued = issued
        self.attrs = attrs or {}
        self.sreg = sreg_ or {}
        self.is_iname = (xri.identifierScheme(openid_) == 'XRI')
    
    def __repr__(self):
        return '<OpenID: %s>' % self.openid
    
    def __str__(self):
        return self.openid

class DjangoOpenIDStore(OpenIDStore):
    def __init__(self):
        self.max_nonce_age = 6 * 60 * 60 # Six hours
    
    def storeAssociation(self, server_url, association):
        assoc = Association(
            server_url = server_url,
            handle = association.handle,
            secret = base64.encodestring(association.secret),
            issued = association.issued,
            lifetime = association.issued,
            assoc_type = association.assoc_type
        )
        assoc.save()
    
    def getAssociation(self, server_url, handle=None):
        assocs = []
        if handle is not None:
            assocs = Association.objects.filter(
                server_url = server_url, handle = handle
            )
        else:
            assocs = Association.objects.filter(
                server_url = server_url
            )
        if not assocs:
            return None
        associations = []
        for assoc in assocs:
            association = OIDAssociation(
                assoc.handle, base64.decodestring(assoc.secret), assoc.issued,
                assoc.lifetime, assoc.assoc_type
            )
            if association.getExpiresIn() == 0:
                self.removeAssociation(server_url, assoc.handle)
            else:
                associations.append((association.issued, association))
        if not associations:
            return None
        return associations[-1][1]
    
    def removeAssociation(self, server_url, handle):
        assocs = list(Association.objects.filter(
            server_url = server_url, handle = handle
        ))
        assocs_exist = len(assocs) > 0
        for assoc in assocs:
            assoc.delete()
        return assocs_exist

    def useNonce(self, server_url, timestamp, salt):
        if abs(timestamp - time.time()) > openid.store.nonce.SKEW:
            return False
        
        query = [
                Q(server_url__exact=server_url),
                Q(timestamp__exact=timestamp),
                Q(salt__exact=salt),
        ]
        try:
            ononce = Nonce.objects.get(reduce(operator.and_, query))
        except Nonce.DoesNotExist:
            ononce = Nonce(
                    server_url=server_url,
                    timestamp=timestamp,
                    salt=salt
            )
            ononce.save()
            return True
        
        ononce.delete()

        return False
   
    def cleanupNonce(self):
        Nonce.objects.filter(timestamp<int(time.time()) - nonce.SKEW).delete()

    def cleaupAssociations(self):
        Association.objects.extra(where=['issued + lifetimeint<(%s)' % time.time()]).delete()

    def getAuthKey(self):
        # Use first AUTH_KEY_LEN characters of md5 hash of SECRET_KEY
        return md5.new(settings.SECRET_KEY).hexdigest()[:self.AUTH_KEY_LEN]
    
    def isDumb(self):
        return False

def from_openid_response(openid_response):
    """ return openid object from response """
    issued = int(time.time())

    try:
        return OpenID(
            openid_response.identity_url, issued, openid_response.signed_fields, 
            dict(sreg.SRegResponse.fromSuccessResponse(openid_response))
            )
    # Hack; early versions of this code were like this and on deletion this was throwing
    # an exception; try to fix this later @todo
    except TypeError:
        return OpenID(
            openid_response.identity_url, issued, openid_response.signed_fields, 
            openid_response.extensionResponse('http://openid.net/sreg/1.0', False)
            )
