# -*- coding: utf-8 -*-
# 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 version 3 for
# more details.
#
# You should have received a copy of the GNU General Public License version 3
# along with this program; if not, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# (c) 2016 Valentin Samir
"""Some utils functions for tests"""
from cas_server.default_settings import settings

import django
from django.test import Client
from django.template import loader
from django.utils import timezone
if django.VERSION < (1, 8):
    from django.template import Context
else:
    Context = lambda x:x

import cgi
import six
from threading import Thread
from lxml import etree
from six.moves import BaseHTTPServer
from six.moves.urllib.parse import urlparse, parse_qsl, parse_qs
from datetime import timedelta

from cas_server import models
from cas_server import utils


def return_unicode(string, charset):
    """make `string` a unicode if `string` is a unicode or bytes encoded with `charset`"""
    if not isinstance(string, six.text_type):
        return string.decode(charset)
    else:
        return string


def return_bytes(string, charset):
    """
        make `string` a bytes encoded with `charset` if `string` is a unicode
        or bytes encoded with `charset`
    """
    if isinstance(string, six.text_type):
        return string.encode(charset)
    else:
        return string


def copy_form(form):
    """Copy form value into a dict"""
    params = {}
    for field in form:
        if field.value():
            params[field.name] = field.value()
        else:
            params[field.name] = ""
    return params


def get_login_page_params(client=None):
    """Return a client and the POST params for the client to login"""
    if client is None:
        client = Client()
    response = client.get('/login')
    params = copy_form(response.context["form"])
    return client, params


def get_auth_client(**update):
    """return a authenticated client"""
    client, params = get_login_page_params()
    params["username"] = settings.CAS_TEST_USER
    params["password"] = settings.CAS_TEST_PASSWORD
    params.update(update)

    response = client.post('/login', params)
    assert client.session.get("authenticated")

    if params.get("service"):
        return (client, response)
    else:
        return client


def get_user_ticket_request(service):
    """Make an auth client to request a ticket for `service`, return the tuple (user, ticket)"""
    client = get_auth_client()
    response = client.get("/login", {"service": service})
    ticket_value = response['Location'].split('ticket=')[-1]
    user = models.User.objects.get(
        username=settings.CAS_TEST_USER,
        session_key=client.session.session_key
    )
    ticket = models.ServiceTicket.objects.get(value=ticket_value)
    return (user, ticket, client)


def get_validated_ticket(service):
    """Return a tick that has being already validated. Used to test SLO"""
    (ticket, auth_client) = get_user_ticket_request(service)[1:3]

    client = Client()
    response = client.get('/validate', {'ticket': ticket.value, 'service': service})
    assert (response.status_code == 200)
    assert (response.content == b'yes\ntest\n')

    ticket = models.ServiceTicket.objects.get(value=ticket.value)
    return (auth_client, ticket)


def get_pgt():
    """return a dict contening a service, user and PGT ticket for this service"""
    (httpd, host, port) = HttpParamsHandler.run()[0:3]
    service = "http://%s:%s" % (host, port)

    (user, ticket) = get_user_ticket_request(service)[:2]

    client = Client()
    client.get('/serviceValidate', {'ticket': ticket.value, 'service': service, 'pgtUrl': service})
    params = httpd.PARAMS

    params["service"] = service
    params["user"] = user

    return params


def get_proxy_ticket(service):
    """Return a ProxyTicket waiting for validation"""
    params = get_pgt()

    # get a proxy ticket
    client = Client()
    response = client.get('/proxy', {'pgt': params['pgtId'], 'targetService': service})
    root = etree.fromstring(response.content)
    proxy_ticket = root.xpath(
        "//cas:proxyTicket",
        namespaces={'cas': "http://www.yale.edu/tp/cas"}
    )
    proxy_ticket = proxy_ticket[0].text
    ticket = models.ProxyTicket.objects.get(value=proxy_ticket)
    return ticket


class HttpParamsHandler(BaseHTTPServer.BaseHTTPRequestHandler):
    """
        A simple http server that return 200 on GET or POST
        and store GET or POST parameters. Used in unit tests
    """

    def do_GET(self):
        """Called on a GET request on the BaseHTTPServer"""
        self.send_response(200)
        self.send_header(b"Content-type", "text/plain")
        self.end_headers()
        self.wfile.write(b"ok")
        url = urlparse(self.path)
        params = dict(parse_qsl(url.query))
        self.server.PARAMS = params

    def do_POST(self):
        """Called on a POST request on the BaseHTTPServer"""
        ctype, pdict = cgi.parse_header(self.headers.get('content-type'))
        if ctype == 'multipart/form-data':
            postvars = cgi.parse_multipart(self.rfile, pdict)
        elif ctype == 'application/x-www-form-urlencoded':
            length = int(self.headers.get('content-length'))
            postvars = parse_qs(self.rfile.read(length), keep_blank_values=1)
        else:
            postvars = {}
        self.server.PARAMS = postvars

    def log_message(self, *args):
        """silent any log message"""
        return

    @classmethod
    def run(cls, port=0):
        """Run a BaseHTTPServer using this class as handler"""
        server_class = BaseHTTPServer.HTTPServer
        httpd = server_class(("127.0.0.1", port), cls)
        (host, port) = httpd.socket.getsockname()

        def lauch():
            """routine to lauch in a background thread"""
            httpd.handle_request()
            httpd.server_close()

        httpd_thread = Thread(target=lauch)
        httpd_thread.daemon = True
        httpd_thread.start()
        return (httpd, host, port)


class Http404Handler(HttpParamsHandler):
    """A simple http server that always return 404 not found. Used in unit tests"""
    def do_GET(self):
        """Called on a GET request on the BaseHTTPServer"""
        self.send_response(404)
        self.send_header(b"Content-type", "text/plain")
        self.end_headers()
        self.wfile.write(b"error 404 not found")

    def do_POST(self):
        """Called on a POST request on the BaseHTTPServer"""
        return self.do_GET()


class DummyCAS(BaseHTTPServer.BaseHTTPRequestHandler):
    """A dummy CAS that validate for only one (service, ticket) used in federated mode tests"""
    def test_params(self):
        """check that internal and provided (service, ticket) matches"""
        if (
            self.server.ticket is not None and
            self.params.get("service").encode("ascii") == self.server.service and
            self.params.get("ticket").encode("ascii") == self.server.ticket
        ):
            self.server.ticket = None
            return True
        else:
            return False

    def send_headers(self, code, content_type):
        """send http headers"""
        self.send_response(code)
        self.send_header("Content-type", content_type)
        self.end_headers()

    def do_GET(self):
        """Called on a GET request on the BaseHTTPServer"""
        url = urlparse(self.path)
        self.params = dict(parse_qsl(url.query))
        if url.path == "/validate":
            self.send_headers(200, "text/plain; charset=utf-8")
            if self.test_params():
                self.wfile.write(b"yes\n" + self.server.username + b"\n")
                self.server.ticket = None
            else:
                self.wfile.write(b"no\n")
        elif url.path in {
            '/serviceValidate', '/serviceValidate',
            '/p3/serviceValidate', '/p3/proxyValidate'
        }:
            self.send_headers(200, "text/xml; charset=utf-8")
            if self.test_params():
                template = loader.get_template('cas_server/serviceValidate.xml')
                context = Context({
                    'username': self.server.username,
                    'attributes': self.server.attributes
                })
                self.wfile.write(return_bytes(template.render(context), "utf8"))
            else:
                template = loader.get_template('cas_server/serviceValidateError.xml')
                context = Context({
                    'code': 'BAD_SERVICE_TICKET',
                    'msg': 'Valids are (%r, %r)' % (self.server.service, self.server.ticket)
                })
                self.wfile.write(return_bytes(template.render(context), "utf8"))
        else:
            self.return_404()

    def do_POST(self):
        """Called on a POST request on the BaseHTTPServer"""
        url = urlparse(self.path)
        self.params = dict(parse_qsl(url.query))
        if url.path == "/samlValidate":
            self.send_headers(200, "text/xml; charset=utf-8")
            length = int(self.headers.get('content-length'))
            root = etree.fromstring(self.rfile.read(length))
            auth_req = root.getchildren()[1].getchildren()[0]
            ticket = auth_req.getchildren()[0].text.encode("ascii")
            if (
                self.server.ticket is not None and
                self.params.get("TARGET").encode("ascii") == self.server.service and
                ticket == self.server.ticket
            ):
                self.server.ticket = None
                template = loader.get_template('cas_server/samlValidate.xml')
                context = Context({
                    'IssueInstant': timezone.now().isoformat(),
                    'expireInstant': (timezone.now() + timedelta(seconds=60)).isoformat(),
                    'Recipient': self.server.service,
                    'ResponseID': utils.gen_saml_id(),
                    'username': self.server.username,
                    'attributes': self.server.attributes,
                })
                self.wfile.write(return_bytes(template.render(context), "utf8"))
            else:
                template = loader.get_template('cas_server/samlValidateError.xml')
                context = Context({
                    'IssueInstant': timezone.now().isoformat(),
                    'ResponseID': utils.gen_saml_id(),
                    'code': 'BAD_SERVICE_TICKET',
                    'msg': 'Valids are (%r, %r)' % (self.server.service, self.server.ticket)
                })
                self.wfile.write(return_bytes(template.render(context), "utf8"))
        else:
            self.return_404()

    def return_404(self):
        """return a 404 error"""
        self.send_headers(404, "text/plain; charset=utf-8")
        self.wfile.write("not found")

    def log_message(self, *args):
        """silent any log message"""
        return

    @classmethod
    def run(cls, service, ticket, username, attributes, port=0):
        """Run a BaseHTTPServer using this class as handler"""
        server_class = BaseHTTPServer.HTTPServer
        httpd = server_class(("127.0.0.1", port), cls)
        httpd.service = service
        httpd.ticket = ticket
        httpd.username = username
        httpd.attributes = attributes
        (host, port) = httpd.socket.getsockname()

        def lauch():
            """routine to lauch in a background thread"""
            httpd.handle_request()
            httpd.server_close()

        httpd_thread = Thread(target=lauch)
        httpd_thread.daemon = True
        httpd_thread.start()
        return (httpd, host, port)


def logout_request(ticket):
    """build a SLO request XML, ready to be send"""
    return u"""<samlp:LogoutRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
 ID="%(id)s" Version="2.0" IssueInstant="%(datetime)s">
<saml:NameID xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"></saml:NameID>
<samlp:SessionIndex>%(ticket)s</samlp:SessionIndex>
</samlp:LogoutRequest>""" % \
        {
            'id': utils.gen_saml_id(),
            'datetime': timezone.now().isoformat(),
            'ticket':  ticket
        }