from threading import Lock

from pprint import pformat

try:

    from cStringIO import StringIO

except ImportError:

    from StringIO import StringIO

from django import http

from django.core import signals

from django.core.handlers.base import BaseHandler

from django.dispatch import dispatcher

from django.utils import datastructures

from django.utils.encoding import force_unicode

# See http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

STATUS_CODE_TEXT = {

    100: 'CONTINUE',

    101: 'SWITCHING PROTOCOLS',

    200: 'OK',

    201: 'CREATED',

    202: 'ACCEPTED',

    203: 'NON-AUTHORITATIVE INFORMATION',

    204: 'NO CONTENT',

    205: 'RESET CONTENT',

    206: 'PARTIAL CONTENT',

    300: 'MULTIPLE CHOICES',

    301: 'MOVED PERMANENTLY',

    302: 'FOUND',

    303: 'SEE OTHER',

    304: 'NOT MODIFIED',

    305: 'USE PROXY',

    306: 'RESERVED',

    307: 'TEMPORARY REDIRECT',

    400: 'BAD REQUEST',

    401: 'UNAUTHORIZED',

    402: 'PAYMENT REQUIRED',

    403: 'FORBIDDEN',

    404: 'NOT FOUND',

    405: 'METHOD NOT ALLOWED',

    406: 'NOT ACCEPTABLE',

    407: 'PROXY AUTHENTICATION REQUIRED',

    408: 'REQUEST TIMEOUT',

    409: 'CONFLICT',

    410: 'GONE',

    411: 'LENGTH REQUIRED',

    412: 'PRECONDITION FAILED',

    413: 'REQUEST ENTITY TOO LARGE',

    414: 'REQUEST-URI TOO LONG',

    415: 'UNSUPPORTED MEDIA TYPE',

    416: 'REQUESTED RANGE NOT SATISFIABLE',

    417: 'EXPECTATION FAILED',

    500: 'INTERNAL SERVER ERROR',

    501: 'NOT IMPLEMENTED',

    502: 'BAD GATEWAY',

    503: 'SERVICE UNAVAILABLE',

    504: 'GATEWAY TIMEOUT',

    505: 'HTTP VERSION NOT SUPPORTED',

}

def safe_copyfileobj(fsrc, fdst, length=16*1024, size=0):

    """

    A version of shutil.copyfileobj that will not read more than 'size' bytes.

    This makes it safe from clients sending more than CONTENT_LENGTH bytes of

    data in the body.

    """

    if not size:

        return

    while size > 0:

        buf = fsrc.read(min(length, size))

        if not buf:

            break

        fdst.write(buf)

        size -= len(buf)

class WSGIRequest(http.HttpRequest):

    def __init__(self, environ):

        self.environ = environ

        self.path = force_unicode(environ['PATH_INFO'])

        self.META = environ

        self.method = environ['REQUEST_METHOD'].upper()

    def __repr__(self):

        # Since this is called as part of error handling, we need to be very

        # robust against potentially malformed input.

        try:

            get = pformat(self.GET)

        except:

            get = '<could not parse>'

        try:

            post = pformat(self.POST)

        except:

            post = '<could not parse>'

        try:

            cookies = pformat(self.COOKIES)

        except:

            cookies = '<could not parse>'

        try:

            meta = pformat(self.META)

        except:

            meta = '<could not parse>'

        return '<WSGIRequest\nGET:%s,\nPOST:%s,\nCOOKIES:%s,\nMETA:%s>' % \

            (get, post, cookies, meta)

    def get_full_path(self):

        return '%s%s' % (self.path, self.environ.get('QUERY_STRING', '') and ('?' + self.environ.get('QUERY_STRING', '')) or '')

    def is_secure(self):

        return 'wsgi.url_scheme' in self.environ \

            and self.environ['wsgi.url_scheme'] == 'https'

    def _load_post_and_files(self):

        # Populates self._post and self._files

        if self.method == 'POST':

            if self.environ.get('CONTENT_TYPE', '').startswith('multipart'):

                header_dict = dict([(k, v) for k, v in self.environ.items() if k.startswith('HTTP_')])

                header_dict['Content-Type'] = self.environ.get('CONTENT_TYPE', '')

                self._post, self._files = http.parse_file_upload(header_dict, self.raw_post_data)

            else:

                self._post, self._files = http.QueryDict(self.raw_post_data, encoding=self._encoding), datastructures.MultiValueDict()

        else:

            self._post, self._files = http.QueryDict('', encoding=self._encoding), datastructures.MultiValueDict()

    def _get_request(self):

        if not hasattr(self, '_request'):

            self._request = datastructures.MergeDict(self.POST, self.GET)

        return self._request

    def _get_get(self):

        if not hasattr(self, '_get'):

            # The WSGI spec says 'QUERY_STRING' may be absent.

            self._get = http.QueryDict(self.environ.get('QUERY_STRING', ''), encoding=self._encoding)

        return self._get

    def _set_get(self, get):

        self._get = get

    def _get_post(self):

        if not hasattr(self, '_post'):

            self._load_post_and_files()

        return self._post

    def _set_post(self, post):

        self._post = post

    def _get_cookies(self):

        if not hasattr(self, '_cookies'):

            self._cookies = http.parse_cookie(self.environ.get('HTTP_COOKIE', ''))

        return self._cookies

    def _set_cookies(self, cookies):

        self._cookies = cookies

    def _get_files(self):

        if not hasattr(self, '_files'):

            self._load_post_and_files()

        return self._files

    def _get_raw_post_data(self):

        try:

            return self._raw_post_data

        except AttributeError:

            buf = StringIO()

            try:

                # CONTENT_LENGTH might be absent if POST doesn't have content at all (lighttpd)

                content_length = int(self.environ.get('CONTENT_LENGTH', 0))

            except ValueError: # if CONTENT_LENGTH was empty string or not an integer

                content_length = 0

            if content_length > 0:

                safe_copyfileobj(self.environ['wsgi.input'], buf,

                        size=content_length)

            self._raw_post_data = buf.getvalue()

            buf.close()

            return self._raw_post_data

    GET = property(_get_get, _set_get)

    POST = property(_get_post, _set_post)

    COOKIES = property(_get_cookies, _set_cookies)

    FILES = property(_get_files)

    REQUEST = property(_get_request)

    raw_post_data = property(_get_raw_post_data)

class WSGIHandler(BaseHandler):

    initLock = Lock()

    request_class = WSGIRequest

    def __call__(self, environ, start_response):

        from django.conf import settings

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

        # settings weren't available.

        if self._request_middleware is None:

            self.initLock.acquire()

            # Check that middleware is still uninitialised.

            if self._request_middleware is None:

                self.load_middleware()

            self.initLock.release()

        dispatcher.send(signal=signals.request_started)

        try:

            try:

                request = self.request_class(environ)

            except UnicodeDecodeError:

                response = http.HttpResponseBadRequest()

            else:

                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)

        try:

            status_text = STATUS_CODE_TEXT[response.status_code]

        except KeyError:

            status_text = 'UNKNOWN STATUS CODE'

        status = '%s %s' % (response.status_code, status_text)

        response_headers = [(str(k), str(v)) for k, v in response.items()]

        for c in response.cookies.values():

            response_headers.append(('Set-Cookie', str(c.output(header=''))))

        start_response(status, response_headers)

        return response