# ⁻*- coding: utf-8 -*-
import default_settings

from django.shortcuts import render, redirect
from django.http import HttpResponse, StreamingHttpResponse
from django.conf import settings
from django.contrib import messages
from django.views.decorators.csrf import csrf_exempt
from django.utils.translation import ugettext as _
from django.core.urlresolvers import reverse 

import requests
import urllib
from datetime import datetime, timedelta
from lxml import etree

import utils
import forms
import models

def _logout(request):
    try: del request.session["authenticated"]
    except KeyError: pass
    try: del request.session["username"]
    except KeyError: pass
    try: del request.session["warn"]
    except KeyError: pass


def redirect_params(url_name, params={}):
    url = reverse(url_name, args = args)
    params = urllib.urlencode(params)
    return HttpResponseRedirect(url + "?%s" % params)

def login(request):
    user = None
    form = None
    service_pattern = None
    renewed = False
    warned = False
    if request.method == 'POST':
        service = request.POST.get('service')
        renew = True if request.POST.get('renew') else False
        gateway = request.POST.get('gateway')
        method = request.POST.get('method')

        if not request.session.get("authenticated") or renew:
            form = forms.UserCredential(request.POST, initial={'service':service,'method':method,'warn':request.session.get("warn")})
            if form.is_valid():
                user = models.User.objects.get(username=form.cleaned_data['username'])
                request.session.set_expiry(0)
                request.session["username"] = form.cleaned_data['username']
                request.session["warn"] = True if form.cleaned_data.get("warn") else False
                request.session["authenticated"] = True
                renewed = True
                warned = True
            else:
                _logout(request)
    else:
        service = request.GET.get('service')
        renew = True if request.GET.get('renew') else False
        gateway = request.GET.get('gateway')
        method = request.GET.get('method')

        if not request.session.get("authenticated") or renew:
            form = forms.UserCredential(initial={'service':service,'method':method,'warn':request.session.get("warn")})
            
    # if authenticated and successfully renewed authentication if needed
    if request.session.get("authenticated") and request.session.get("username") and (not renew or renewed):
        try:
            user = models.User.objects.get(username=request.session["username"])
        except models.User.DoesNotExist:
            _logout(request)
            return redirect_params("login", params=dict(request.GET))

        # if login agains a service is requestest
        if service:
            try:
                # is the service allowed
                service_pattern = models.ServicePattern.validate(service)
                # is the current user allowed on this service
                service_pattern.check_user(user)
                # if the user has asked to be warned before any login to a service (no transparent SSO)
                if request.session.get("warn", True) and not warned:
                    messages.add_message(request, messages.WARNING, _(u"Authentication has been required by service %(name)s (%(url)s)") % {'name':service_pattern.name, 'url':service})
                    return render(request, settings.CAS_WARN_TEMPLATE, {'service_ticket_url':user.get_service_url(service, service_pattern, renew=renew)})
                else:
                    return redirect(user.get_service_url(service, service_pattern, renew=renew)) # redirect, using method ?
            except models.ServicePattern.DoesNotExist:
                messages.add_message(request, messages.ERROR, _(u'Service %(url)s non allowed.') % {'url' : service})
            except models.BadUsername:
                messages.add_message(request, messages.ERROR, _(u"Username non allowed"))
            except models.BadFilter:
                messages.add_message(request, messages.ERROR, _(u"User charateristics non allowed"))
            except models.UserFieldNotDefined:
                messages.add_message(request, messages.ERROR, _(u"The attribut %(field)s is needed to use that service") % {'field':service_pattern.user_field})

            # if gateway is set and auth failed redirect to the service without authentication
            if gateway:
                list(messages.get_messages(request)) # clean messages before leaving the django app
                return redirect(service)

        return render(request, settings.CAS_LOGGED_TEMPLATE, {'session':request.session})
    else:
        if service:
            try:
                service_pattern = models.ServicePattern.validate(service)
                if gateway:
                    list(messages.get_messages(request)) # clean messages before leaving the django app
                    return redirect(service)
                if request.session.get("authenticated") and renew:
                    messages.add_message(request, messages.WARNING, _(u"Authentication renewal required by service %(name)s (%(url)s).") % {'name':service_pattern.name, 'url':service})
                else:
                    messages.add_message(request, messages.WARNING, _(u"Authentication required by service %(name)s (%(url)s).") % {'name':service_pattern.name, 'url':service})
            except models.ServicePattern.DoesNotExist:
                messages.add_message(request, messages.ERROR, _(u'Service %s non allowed') % service)
        return render(request, settings.CAS_LOGIN_TEMPLATE, {'form':form})

def logout(request):
    service = request.GET.get('service')
    if request.session.get("authenticated"):
        user = models.User.objects.get(username=request.session["username"])
        user.logout(request)
        user.delete()
        _logout(request)
    # if service is set, redirect to service after logout
    if service:
        list(messages.get_messages(request)) # clean messages before leaving the django app
        return redirect(service)
    # else redirect to login page
    else:
        messages.add_message(request, messages.SUCCESS, _(u'Successfully logout'))
        return redirect("login")

def validate(request):
    service = request.GET.get('service')
    ticket = request.GET.get('ticket')
    renew = True if request.GET.get('renew') else False
    if service and ticket:
        try:
            ticket = models.ServiceTicket.objects.get(value=ticket, service=service, validate=False, renew=renew, creation__gt=(datetime.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY)))
            ticket.validate = True
            ticket.save()
            return HttpResponse("yes\n", content_type="text/plain")
        except models.ServiceTicket.DoesNotExist:
            return HttpResponse("no\n", content_type="text/plain")
    else:
        return HttpResponse("no\n", content_type="text/plain")

    
def psValidate(request, typ=['ST']):
    service = request.GET.get('service')
    ticket = request.GET.get('ticket')
    pgtUrl = request.GET.get('pgtUrl')
    renew = True if request.GET.get('renew') else False
    if service and ticket:
        for t in typ:
            if ticket.startswith(t):
                break
        else:
            return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_TICKET'}, content_type="text/xml; charset=utf-8")
        try:
            proxies = []
            if ticket.startswith("ST"):
                ticket = models.ServiceTicket.objects.get(value=ticket, service=service, validate=False, renew=renew, creation__gt=(datetime.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY)))
            elif ticket.startswith("PT"):
                ticket = models.ProxyTicket.objects.get(value=ticket, service=service, validate=False, renew=renew, creation__gt=(datetime.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY)))
                for p in ticket.proxies.all():
                    proxies.append(p.url)
            ticket.validate = True
            ticket.save()
            attributes = []
            for key, value in ticket.attributs.items():
                if isinstance(value, list):
                    for v in value:
                        attributes.append((key, v))
                else:
                    attributes.append((key, value))
            params = {'username':ticket.user.username, 'attributes':attributes, 'proxies':proxies}
            if ticket.service_pattern.user_field and ticket.user.attributs.get(ticket.service_pattern.user_field):
                params['username'] = ticket.user.attributs.get(ticket.service_pattern.user_field)
            if pgtUrl and pgtUrl.startswith("https://"):
                pattern = models.ServicePattern.validate(pgtUrl)
                if pattern.proxy:
                    proxyid = models._gen_ticket('PGTIOU')
                    pticket = models.ProxyGrantingTicket.objects.create(user=ticket.user, service=pgtUrl, service_pattern=pattern)
                    url = utils.update_url(pgtUrl, {'pgtIou':proxyid, 'pgtId':pticket.value})
                    try:
                        r = requests.get(url, verify=settings.CAS_PROXY_CA_CERTIFICATE_PATH)
                        if r.status_code == 200:
                            params['proxyGrantingTicket'] = proxyid
                        else:
                            pticket.delete()
                        return render(request, "cas_server/serviceValidate.xml", params, content_type="text/xml; charset=utf-8")
                    except requests.exceptions.SSLError:
                        return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_PROXY_CALLBACK'}, content_type="text/xml; charset=utf-8")
                else:
                    return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_PROXY_CALLBACK'}, content_type="text/xml; charset=utf-8")
            else:
                return render(request, "cas_server/serviceValidate.xml", params, content_type="text/xml; charset=utf-8")
        except (models.ServiceTicket.DoesNotExist, models.ProxyTicket.DoesNotExist, models.ServicePattern.DoesNotExist):
            return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_TICKET'}, content_type="text/xml; charset=utf-8")
    else:
        return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_REQUEST'}, content_type="text/xml; charset=utf-8")

def serviceValidate(request):
    return psValidate(request)
def proxyValidate(request):
    return psValidate(request, ["ST", "PT"])

def proxy(request):
    pgt = request.GET.get('pgt')
    targetService = request.GET.get('targetService')
    if pgt and targetService:
        try:
            pattern = models.ServicePattern.validate(targetService)
            ticket = models.ProxyGrantingTicket.objects.get(value=pgt, creation__gt=(datetime.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY)))
            pattern.check_user(ticket.user)
            pticket = ticket.user.get_ticket(models.ProxyTicket, targetService, pattern, False)
            pticket.proxies.create(url=ticket.service)
            return render(request, "cas_server/proxy.xml", {'ticket':pticket.value}, content_type="text/xml; charset=utf-8")
        except (models.ProxyGrantingTicket.DoesNotExist, models.ServicePattern.DoesNotExist, models.BadUsername, models.BadFilter):
            return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_TICKET'}, content_type="text/xml; charset=utf-8")
    else:
        return render(request, "cas_server/serviceValidateError.xml", {'code':'INVALID_REQUEST'}, content_type="text/xml; charset=utf-8")

def p3_serviceValidate(request):
    return serviceValidate(request)

def p3_proxyValidate(request):
    return proxyValidate(request)

@csrf_exempt
def samlValidate(request):
    if request.method == 'POST':
        target = request.GET.get('TARGET')
        root = etree.fromstring(request.body)
        try:
            auth_req = root.getchildren()[1].getchildren()[0]
            IssueInstant = auth_req.attrib['IssueInstant']
            RequestID = auth_req.attrib['RequestID']
            ticket = auth_req.getchildren()[0].text
            ticket = models.ServiceTicket.objects.get(value=ticket, service=target, validate=False, creation__gt=(datetime.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY)))
            ticket.validate = True
            ticket.save()
            expireInstant = (ticket.creation + timedelta(seconds=settings.CAS_TICKET_VALIDITY)).isoformat()
            attributes = []
            for key, value in ticket.attributs.items():
                if isinstance(value, list):
                    for v in value:
                        attributes.append((key, v))
                else:
                    attributes.append((key, value))
            params = {'IssueInstant':IssueInstant, 'expireInstant':expireInstant,'Recipient':target, 'ResponseID':RequestID, 'username':ticket.user.username, 'attributes':attributes}
            if ticket.service_pattern.user_field and ticket.user.attributs.get(ticket.service_pattern.user_field):
                params['username'] = ticket.user.attributs.get(ticket.service_pattern.user_field)
            return render(request, "cas_server/samlValidate.xml", params, content_type="text/xml; charset=utf-8")
        except IndexError:
            return render(request, "cas_server/samlValidateError.xml", {'code':'VersionMismatch'}, content_type="text/xml; charset=utf-8")
        except KeyError:
            return render(request, "cas_server/samlValidateError.xml", {'code':'VersionMismatch'}, content_type="text/xml; charset=utf-8")
        except models.ServiceTicket.DoesNotExist:
            return render(request, "cas_server/samlValidateError.xml", {'code':'AuthnFailed'}, content_type="text/xml; charset=utf-8")
    else:
        return redirect("login")