import logging
from io import BytesIO

from django.core.handlers.wsgi import WSGIRequest
from django.core.servers.basehttp import WSGIRequestHandler
from django.test import SimpleTestCase
from django.test.client import RequestFactory
from django.test.utils import captured_stderr, patch_logger


class Stub(object):
    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)


class WSGIRequestHandlerTestCase(SimpleTestCase):

    def test_log_message(self):
        # Silence the django.server logger by replacing its StreamHandler with
        # NullHandler.
        logger = logging.getLogger('django.server')
        original_handlers = logger.handlers
        logger.handlers = [logging.NullHandler()]
        try:
            request = WSGIRequest(RequestFactory().get('/').environ)
            request.makefile = lambda *args, **kwargs: BytesIO()
            handler = WSGIRequestHandler(request, '192.168.0.2', None)
            level_status_codes = {
                'info': [200, 301, 304],
                'warning': [400, 403, 404],
                'error': [500, 503],
            }

            def _log_level_code(level, status_code):
                with patch_logger('django.server', level) as messages:
                    handler.log_message('GET %s %s', 'A', str(status_code))
                return messages

            for level, status_codes in level_status_codes.items():
                for status_code in status_codes:
                    # The correct level gets the message.
                    messages = _log_level_code(level, status_code)
                    self.assertIn('GET A %d' % status_code, messages[0])

                    # Incorrect levels shouldn't have any messages.
                    for wrong_level in level_status_codes.keys():
                        if wrong_level != level:
                            messages = _log_level_code(wrong_level, status_code)
                            self.assertEqual(len(messages), 0)
        finally:
            logger.handlers = original_handlers

    def test_https(self):
        request = WSGIRequest(RequestFactory().get('/').environ)
        request.makefile = lambda *args, **kwargs: BytesIO()

        handler = WSGIRequestHandler(request, '192.168.0.2', None)

        with patch_logger('django.server', 'error') as messages:
            handler.log_message("GET %s %s", str('\x16\x03'), "4")
        self.assertIn(
            "You're accessing the development server over HTTPS, "
            "but it only supports HTTP.",
            messages[0]
        )

    def test_strips_underscore_headers(self):
        """WSGIRequestHandler ignores headers containing underscores.

        This follows the lead of nginx and Apache 2.4, and is to avoid
        ambiguity between dashes and underscores in mapping to WSGI environ,
        which can have security implications.
        """
        def test_app(environ, start_response):
            """A WSGI app that just reflects its HTTP environ."""
            start_response('200 OK', [])
            http_environ_items = sorted(
                '%s:%s' % (k, v) for k, v in environ.items()
                if k.startswith('HTTP_')
            )
            yield (','.join(http_environ_items)).encode('utf-8')

        rfile = BytesIO()
        rfile.write(b"GET / HTTP/1.0\r\n")
        rfile.write(b"Some-Header: good\r\n")
        rfile.write(b"Some_Header: bad\r\n")
        rfile.write(b"Other_Header: bad\r\n")
        rfile.seek(0)

        # WSGIRequestHandler closes the output file; we need to make this a
        # no-op so we can still read its contents.
        class UnclosableBytesIO(BytesIO):
            def close(self):
                pass

        wfile = UnclosableBytesIO()

        def makefile(mode, *a, **kw):
            if mode == 'rb':
                return rfile
            elif mode == 'wb':
                return wfile

        request = Stub(makefile=makefile)
        server = Stub(base_environ={}, get_app=lambda: test_app)

        # We don't need to check stderr, but we don't want it in test output
        with captured_stderr():
            # instantiating a handler runs the request as side effect
            WSGIRequestHandler(request, '192.168.0.2', server)

        wfile.seek(0)
        body = list(wfile.readlines())[-1]

        self.assertEqual(body, b'HTTP_SOME_HEADER:good')
