import urllib

import sys

from cStringIO import StringIO

from django.conf import settings

from django.contrib.auth import authenticate, login

from django.core.handlers.base import BaseHandler

from django.core.handlers.wsgi import WSGIRequest

from django.core.signals import got_request_exception

from django.dispatch import dispatcher

from django.http import SimpleCookie, HttpRequest

from django.template import TemplateDoesNotExist

from django.test import signals

from django.utils.functional import curry

from django.utils.encoding import smart_str

from django.utils.http import urlencode

from django.utils.itercompat import is_iterable

BOUNDARY = 'BoUnDaRyStRiNg'

MULTIPART_CONTENT = 'multipart/form-data; boundary=%s' % BOUNDARY

class ClientHandler(BaseHandler):

    """

    A HTTP Handler that can be used for testing purposes.

    Uses the WSGI interface to compose requests, but returns

    the raw HttpResponse object

    """

    def __call__(self, environ):

        from django.conf import settings

        from django.core import signals

        # Set up middleware if needed. We couldn't do this earlier, because

        # settings weren't available.

        if self._request_middleware is None:

            self.load_middleware()

        dispatcher.send(signal=signals.request_started)

        try:

            request = WSGIRequest(environ)

            response = self.get_response(request)

            # Apply response middleware

            for middleware_method in self._response_middleware:

                response = middleware_method(request, response)

            response = self.apply_response_fixes(request, response)

        finally:

            dispatcher.send(signal=signals.request_finished)

        return response

def store_rendered_templates(store, signal, sender, template, context):

    "A utility function for storing templates and contexts that are rendered"

    store.setdefault('template',[]).append(template)

    store.setdefault('context',[]).append(context)

def encode_multipart(boundary, data):

    """

    A simple method for encoding multipart POST data from a dictionary of

    form values.

    The key will be used as the form data name; the value will be transmitted

    as content. If the value is a file, the contents of the file will be sent

    as an application/octet-stream; otherwise, str(value) will be sent.

    """

    lines = []

    to_str = lambda s: smart_str(s, settings.DEFAULT_CHARSET)

    for (key, value) in data.items():

        if isinstance(value, file):

            lines.extend([

                '--' + boundary,

                'Content-Disposition: form-data; name="%s"; filename="%s"' % (to_str(key), to_str(value.name)),

                'Content-Type: application/octet-stream',

                '',

                value.read()

            ])

        else:

            if not isinstance(value, basestring) and is_iterable(value):

                for item in value:

                    lines.extend([

                        '--' + boundary,

                        'Content-Disposition: form-data; name="%s"' % to_str(key),

                        '',

                        to_str(item)

                    ])

            else:

                lines.extend([

                    '--' + boundary,

                    'Content-Disposition: form-data; name="%s"' % to_str(key),

                    '',

                    to_str(value)

                ])

    lines.extend([

        '--' + boundary + '--',

        '',

    ])

    return '\r\n'.join(lines)

class Client:

    """

    A class that can act as a client for testing purposes.

    It allows the user to compose GET and POST requests, and

    obtain the response that the server gave to those requests.

    The server Response objects are annotated with the details

    of the contexts and templates that were rendered during the

    process of serving the request.

    Client objects are stateful - they will retain cookie (and

    thus session) details for the lifetime of the Client instance.

    This is not intended as a replacement for Twill/Selenium or

    the like - it is here to allow testing against the

    contexts and templates produced by a view, rather than the

    HTML rendered to the end-user.

    """

    def __init__(self, **defaults):

        self.handler = ClientHandler()

        self.defaults = defaults

        self.cookies = SimpleCookie()

        self.exc_info = None

    def store_exc_info(self, *args, **kwargs):

        """

        Utility method that can be used to store exceptions when they are

        generated by a view.

        """

        self.exc_info = sys.exc_info()

    def _session(self):

        "Obtain the current session variables"

        if 'django.contrib.sessions' in settings.INSTALLED_APPS:

            engine = __import__(settings.SESSION_ENGINE, {}, {}, [''])

            cookie = self.cookies.get(settings.SESSION_COOKIE_NAME, None)

            if cookie:

                return engine.SessionStore(cookie.value)

        return {}

    session = property(_session)

    def request(self, **request):

        """

        The master request method. Composes the environment dictionary

        and passes to the handler, returning the result of the handler.

        Assumes defaults for the query environment, which can be overridden

        using the arguments to the request.

        """

        environ = {

            'HTTP_COOKIE':      self.cookies,

            'PATH_INFO':         '/',

            'QUERY_STRING':      '',

            'REQUEST_METHOD':    'GET',

            'SCRIPT_NAME':       None,

            'SERVER_NAME':       'testserver',

            'SERVER_PORT':       80,

            'SERVER_PROTOCOL':   'HTTP/1.1',

        }

        environ.update(self.defaults)

        environ.update(request)

        # Curry a data dictionary into an instance of

        # the template renderer callback function

        data = {}

        on_template_render = curry(store_rendered_templates, data)

        dispatcher.connect(on_template_render, signal=signals.template_rendered)

        # Capture exceptions created by the handler

        dispatcher.connect(self.store_exc_info, signal=got_request_exception)

        try:

            response = self.handler(environ)

        except TemplateDoesNotExist, e:

            # If the view raises an exception, Django will attempt to show

            # the 500.html template. If that template is not available,

            # we should ignore the error in favor of re-raising the

            # underlying exception that caused the 500 error. Any other

            # template found to be missing during view error handling

            # should be reported as-is.

            if e.args != ('500.html',):

                raise

        # Look for a signalled exception and reraise it

        if self.exc_info:

            raise self.exc_info[1], None, self.exc_info[2]

        # Save the client and request that stimulated the response

        response.client = self

        response.request = request

        # Add any rendered template detail to the response

        # If there was only one template rendered (the most likely case),

        # flatten the list to a single element

        for detail in ('template', 'context'):

            if data.get(detail):

                if len(data[detail]) == 1:

                    setattr(response, detail, data[detail][0]);

                else:

                    setattr(response, detail, data[detail])

            else:

                setattr(response, detail, None)

        # Update persistent cookie data

        if response.cookies:

            self.cookies.update(response.cookies)

        return response

    def get(self, path, data={}, **extra):

        "Request a response from the server using GET."

        r = {

            'CONTENT_LENGTH':  None,

            'CONTENT_TYPE':    'text/html; charset=utf-8',

            'PATH_INFO':       urllib.unquote(path),

            'QUERY_STRING':    urlencode(data, doseq=True),

            'REQUEST_METHOD': 'GET',

        }

        r.update(extra)

        return self.request(**r)

    def post(self, path, data={}, content_type=MULTIPART_CONTENT, **extra):

        "Request a response from the server using POST."

        if content_type is MULTIPART_CONTENT:

            post_data = encode_multipart(BOUNDARY, data)

        else:

            post_data = data

        r = {

            'CONTENT_LENGTH': len(post_data),

            'CONTENT_TYPE':   content_type,

            'PATH_INFO':      urllib.unquote(path),

            'REQUEST_METHOD': 'POST',

            'wsgi.input':     StringIO(post_data),

        }

        r.update(extra)

        return self.request(**r)

    def login(self, **credentials):

        """Set the Client to appear as if it has sucessfully logged into a site.

        Returns True if login is possible; False if the provided credentials

        are incorrect, or the user is inactive, or if the sessions framework is

        not available.

        """

        user = authenticate(**credentials)

        if user and user.is_active and 'django.contrib.sessions' in settings.INSTALLED_APPS:

            engine = __import__(settings.SESSION_ENGINE, {}, {}, [''])

            # Create a fake request to store login details

            request = HttpRequest()

            request.session = engine.SessionStore()

            login(request, user)

            # Set the cookie to represent the session

            self.cookies[settings.SESSION_COOKIE_NAME] = request.session.session_key

            self.cookies[settings.SESSION_COOKIE_NAME]['max-age'] = None

            self.cookies[settings.SESSION_COOKIE_NAME]['path'] = '/'

            self.cookies[settings.SESSION_COOKIE_NAME]['domain'] = settings.SESSION_COOKIE_DOMAIN

            self.cookies[settings.SESSION_COOKIE_NAME]['secure'] = settings.SESSION_COOKIE_SECURE or None

            self.cookies[settings.SESSION_COOKIE_NAME]['expires'] = None

            # Save the session values

            request.session.save()

            return True

        else:

            return False

    def logout(self):

        """Removes the authenticated user's cookies.

        Causes the authenticated user to be logged out.

        """

        session = __import__(settings.SESSION_ENGINE, {}, {}, ['']).SessionStore()

        session.delete(session_key=self.cookies[settings.SESSION_COOKIE_NAME].value)

        self.cookies = SimpleCookie()