import urllib
import sys
import os
try:
    from cStringIO import StringIO
except ImportError:
    from StringIO 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.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 FakePayload(object):
    """
    A wrapper around StringIO that restricts what can be read since data from
    the network can't be seeked and cannot be read outside of its content
    length. This makes sure that views can't do anything under the test client
    that wouldn't work in Real Life.
    """
    def __init__(self, content):
        self.__content = StringIO(content)
        self.__len = len(content)

    def read(self, num_bytes=None):
        if num_bytes is None:
            num_bytes = self.__len or 1
        assert self.__len >= num_bytes, "Cannot read more than the available bytes from the HTTP incoming data."
        content = self.__content.read(num_bytes)
        self.__len -= num_bytes
        return content


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()

        signals.request_started.send(sender=self.__class__)
        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:
            signals.request_finished.send(sender=self.__class__)

        return response

def store_rendered_templates(store, signal, sender, template, context, **kwargs):
    """
    Stores templates and contexts that are rendered.
    """
    store.setdefault('template',[]).append(template)
    store.setdefault('context',[]).append(context)

def encode_multipart(boundary, data):
    """
    Encodes 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)

    # Not by any means perfect, but good enough for our purposes.
    is_file = lambda thing: hasattr(thing, "read") and callable(thing.read)

    # Each bit of the multipart form data could be either a form value or a
    # file, or a *list* of form values and/or files. Remember that HTTP field
    # names can be duplicated!
    for (key, value) in data.items():
        if is_file(value):
            lines.extend(encode_file(boundary, key, value))
        elif not isinstance(value, basestring) and is_iterable(value):
            for item in value:
                if is_file(item):
                    lines.extend(encode_file(boundary, key, item))
                else:
                    lines.extend([
                        '--' + boundary,
                        'Content-Disposition: form-data; name="%s"' % to_str(key),
                        '',