##
## authentication.py
## Login : <uli@pu.smp.net>
## Started on  Tue Jul 27 14:26:35 2010 Uli Fouquet
## $Id$
## 
## Copyright (C) 2010 Uli Fouquet
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
## 
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
## 
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##
"""Special authentication for applicants.

   XXX: This is work in progress, experimental code! Don't do that at home!
"""
import grok
from zope.event import notify
from zope.pluggableauth.factories import Principal
from zope.pluggableauth.interfaces import (
    ICredentialsPlugin, IAuthenticatorPlugin, IPrincipalInfo,
    IAuthenticatedPrincipalFactory, AuthenticatedPrincipalCreated)
from zope.pluggableauth.plugins.session import SessionCredentialsPlugin
from zope.publisher.interfaces import IRequest
from zope.publisher.interfaces.http import IHTTPRequest
from zope.session.interfaces import ISession
from waeup.sirp.authentication import Account, PrincipalInfo
from waeup.sirp.jambtables.interfaces import (
    IApplicantPrincipalInfo, IApplicantPrincipal, IApplicantSessionCredentials,
    IJAMBApplicantSessionCredentials)
from waeup.sirp.jambtables.util import get_applicant_data, get_access_code

class PortalUser(grok.Role):
    """A role for applicants.
    """
    grok.name('waeup.Applicant')
    grok.permissions('waeup.Public')

class ApplicantAccount(Account):
    """An account for applicants.

    XXX: Very likely we do not need this at all.
    """
    def __init__(self, reg_no, ac):
        self.name = u'applicant'
        self.title = u'Applicant'
        self.description = u'Applicant'
        self.reg_no = reg_no
        self.access_code = ac
        roles = ['waeup.Applicant']
        self.setRoles(roles)

    def checkPassword(self, reg_no, ac):
        """Check whether the given credentials exist.

        `reg_no` is a JAMB registration number. `ac` an access code
        string like ``PUDE-23-1234567890``.
        """
        if self.reg_no != reg_no or self.access_code != ac:
            return False
        return True
        site = grok.getSite()
        if not reg_no in site['applications']:
            return False
        data = get_applicant_data(reg_no, ac)
        if data is None:
            return False
        return True

class ApplicantPrincipalInfo(object):
    """Infos about an applicant principal.
    """
    grok.implements(IApplicantPrincipalInfo)

    # def __init__(self, id, title, description):
    # def __init__(self, reg_no, access_code):
    def __init__(self, access_code, jamb_reg_no=None):
        self.id = principal_id(access_code, jamb_reg_no)
        self.title = u'Applicant'
        self.description = u'An Applicant'
        self.credentialsPlugin = None
        self.authenticatorPlugin = None
        self.reg_no = jamb_reg_no
        self.access_code = access_code

class ApplicantPrincipal(Principal):
    """An applicant principal.

    Applicant principals provide an extra `access_code` and `reg_no`
    attribute extending ordinary principals.
    """

    grok.implements(IApplicantPrincipal)

    def __init__(self, reg_no, access_code):
        self.id = '%s-%s' % (reg_no, access_code)
        self.title = u'Applicant'
        self.description = u'An applicant'
        self.groups = []
        self.reg_no = reg_no
        self.access_code = access_code

    def __repr__(self):
        return 'ApplicantPrincipal(%r)' % self.id

class AuthenticatedApplicantPrincipalFactory(grok.MultiAdapter):
    """Creates 'authenticated' applicant principals.

    Adapts (principal info, request) to an ApplicantPrincipal instance.

    This adapter is used by the standard PAU to transform
    PrincipalInfos into Principal instances.
    """
    grok.adapts(IApplicantPrincipalInfo, IRequest)
    grok.implements(IAuthenticatedPrincipalFactory)

    def __init__(self, info, request):
        self.info = info
        self.request = request

    def __call__(self, authentication):
        principal = ApplicantPrincipal(
            authentication.prefix + self.info.reg_no,
            self.info.access_code
            )
        notify(
            AuthenticatedPrincipalCreated(
                authentication, principal, self.info, self.request))
        return principal


#
# Credentials plugins and related....
#

class ApplicantCredentials(object):
    """Credentials class for ordinary applicants.
    """
    grok.implements(IApplicantSessionCredentials)

    def __init__(self, access_code):
        self.access_code = access_code

    def getAccessCode(self):
        """Get the access code.
        """
        return self.access_code

    def getLogin(self):
        """Stay compatible with non-applicant authenticators.
        """
        return None

    def getPassword(self):
        """Stay compatible with non-applicant authenticators.
        """
        return None
    
class JAMBApplicantCredentials(ApplicantCredentials):
    """Credentials class for JAMB-screened applicants.
    """
    grok.implements(IJAMBApplicantSessionCredentials)

    def __init__(self, access_code, jamb_reg_no):
        self.access_code = access_code
        self.jamb_reg_no = jamb_reg_no

    def getJAMBRegNo(self):
        """Get the JAMB registration no.
        """
        return self.jamb_reg_no

class WAeUPApplicantCredentialsPlugin(grok.GlobalUtility,
                                      SessionCredentialsPlugin):
    """A credentials plugin that scans requests for applicant credentials.
    """
    grok.provides(ICredentialsPlugin)
    grok.name('applicant_credentials')

    loginpagename = 'login'
    accesscode_prefix_field = 'form.prefix'
    accesscode_series_field = 'form.ac_series'
    accesscode_number_field = 'form.ac_number'
    jamb_reg_no_field = 'form.jamb_reg_no'

    def extractCredentials(self, request):
        """Extracts credentials from a session if they exist.
        """
        if not IHTTPRequest.providedBy(request):
            return None
        session = ISession(request)
        sessionData = session.get(
            'zope.pluggableauth.browserplugins')
        access_code_prefix = request.get(self.accesscode_prefix_field, None)
        access_code_series = request.get(self.accesscode_series_field, None)
        access_code_no = request.get(self.accesscode_number_field, None)
        jamb_reg_no = request.get(self.jamb_reg_no_field, None)
        access_code = '%s-%s-%s' % (
            access_code_prefix, access_code_series, access_code_no)
        if None in [access_code_prefix, access_code_series, access_code_no]:
            access_code = None
        credentials = None

        print "CRED2: %s, %s" % (access_code, jamb_reg_no)
        if access_code and jamb_reg_no:
            credentials = JAMBApplicantCredentials(
                access_code, jamb_reg_no)
        elif access_code:
            credentials = ApplicantCredentials(access_code)
        elif not sessionData:
            return None
        sessionData = session[
            'zope.pluggableauth.browserplugins']
        if credentials:
            sessionData['credentials'] = credentials
        else:
            credentials = sessionData.get('credentials', None)
        if not credentials:
            return None
        if credentials.getJAMBRegNo() is not None:
            return {'accesscode': credentials.getAccessCode(),
                    'jambregno': credentials.getJAMBRegNo()}
        return {'accesscode': credentials.getAccessCode()}


class ApplicantsAuthenticatorPlugin(grok.GlobalUtility):
    """Authenticate applicants.

    XXX: This plugin currently accepts any input and authenticates the
    user as applicant.
    """
    grok.provides(IAuthenticatorPlugin)
    grok.name('applicants')

    def authenticateCredentials(self, credentials):
        if not isinstance(credentials, dict):
            return None
        if not 'accesscode' in credentials.keys():
            return None
        if not 'jambregno' in credentials.keys():
            credentials['jambregno'] = None
        ac = get_access_code(credentials['accesscode'])
        if ac is None:
            # Invalid access code entered.
            # XXX: log this.
            return None
        return ApplicantPrincipalInfo(
            credentials['accesscode'], credentials['jambregno']
            )

    def principalInfo(self, id):
        """Returns an IPrincipalInfo object for the specified principal id.

        This method is used by the stadard PAU to lookup for instance
        groups. If a principal belongs to a group, the group is looked
        up by the id.  Currently we always return ``None``,
        indicating, that the principal could not be found. This also
        means, that is has no effect if applicant users belong to a
        certain group. They can not gain extra-permissions this way.
        """
        return None

def principal_id(access_code, jamb_reg_no=None):
    """Get a principal ID for applicants.

    We need unique principal ids for appliants. As access codes must
    be unique we simply return them.
    """
    return access_code