# -*- 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

from django.test import Client
from django.template import loader, Context
from django.utils import timezone

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
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)

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

    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 = cgi.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
        }