import os

from pprint import pformat

from django import http

from django.core import signals

from django.core.handlers.base import BaseHandler

from django.core.urlresolvers import set_script_prefix

from django.utils import datastructures

from django.utils.encoding import force_unicode, smart_str, iri_to_uri

# NOTE: do *not* import settings (or any module which eventually imports

# settings) until after ModPythonHandler has been called; otherwise os.environ

# won't be set up correctly (with respect to settings).

class ModPythonRequest(http.HttpRequest):

    def __init__(self, req):

        self._req = req

        # FIXME: This isn't ideal. The request URI may be encoded (it's

        # non-normalized) slightly differently to the "real" SCRIPT_NAME

        # and PATH_INFO values. This causes problems when we compute path_info,

        # below. For now, don't use script names that will be subject to

        # encoding/decoding.

        self.path = force_unicode(req.uri)

        root = req.get_options().get('django.root', '')

        self.django_root = root

        # req.path_info isn't necessarily computed correctly in all

        # circumstances (it's out of mod_python's control a bit), so we use

        # req.uri and some string manipulations to get the right value.

        if root and req.uri.startswith(root):

            self.path_info = force_unicode(req.uri[len(root):])

        else:

            self.path_info = self.path

        if not self.path_info:

            # Django prefers empty paths to be '/', rather than '', to give us

            # a common start character for URL patterns. So this is a little

            # naughty, but also pretty harmless.

            self.path_info = u'/'

        self._post_parse_error = False

    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>'

        if self._post_parse_error:

            post = '<could not parse>'

        else:

            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 smart_str(u'<ModPythonRequest\npath:%s,\nGET:%s,\nPOST:%s,\nCOOKIES:%s,\nMETA:%s>' %

                         (self.path, unicode(get), unicode(post),

                          unicode(cookies), unicode(meta)))

    def get_full_path(self):

        # RFC 3986 requires self._req.args to be in the ASCII range, but this

        # doesn't always happen, so rather than crash, we defensively encode it.

        return '%s%s' % (self.path, self._req.args and ('?' + iri_to_uri(self._req.args)) or '')

    def is_secure(self):

        try:

            return self._req.is_https()

        except AttributeError:

            # mod_python < 3.2.10 doesn't have req.is_https().

            return self._req.subprocess_env.get('HTTPS', '').lower() in ('on', '1')

    def _load_post_and_files(self):

        "Populates self._post and self._files"

        if self.method != 'POST':

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

            return

        if 'content-type' in self._req.headers_in and self._req.headers_in['content-type'].startswith('multipart'):

            self._raw_post_data = ''

            try:

                self._post, self._files = self.parse_file_upload(self.META, self._req)

            except:

                # See django.core.handlers.wsgi.WSGIHandler for an explanation

                # of what's going on here.

                self._post = http.QueryDict('')

                self._files = datastructures.MultiValueDict()

                self._post_parse_error = True

                raise

        else:

            self._post, self._files = http.QueryDict(self.raw_post_data, 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'):

            self._get = http.QueryDict(self._req.args, 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._req.headers_in.get('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_meta(self):

        "Lazy loader that returns self.META dictionary"

        if not hasattr(self, '_meta'):

            self._meta = {

                'AUTH_TYPE':         self._req.ap_auth_type,

                'CONTENT_LENGTH':    self._req.clength, # This may be wrong

                'CONTENT_TYPE':      self._req.content_type, # This may be wrong

                'GATEWAY_INTERFACE': 'CGI/1.1',

                'PATH_INFO':         self.path_info,

                'PATH_TRANSLATED':   None, # Not supported

                'QUERY_STRING':      self._req.args,

                'REMOTE_ADDR':       self._req.connection.remote_ip,

                'REMOTE_HOST':       None, # DNS lookups not supported

                'REMOTE_IDENT':      self._req.connection.remote_logname,

                'REMOTE_USER':       self._req.user,

                'REQUEST_METHOD':    self._req.method,

                'SCRIPT_NAME':       self.django_root,

                'SERVER_NAME':       self._req.server.server_hostname,

                'SERVER_PORT':       self._req.server.port,

                'SERVER_PROTOCOL':   self._req.protocol,

                'SERVER_SOFTWARE':   'mod_python'

            }

            for key, value in self._req.headers_in.items():

                key = 'HTTP_' + key.upper().replace('-', '_')

                self._meta[key] = value

        return self._meta

    def _get_raw_post_data(self):

        try:

            return self._raw_post_data

        except AttributeError:

            self._raw_post_data = self._req.read()

            return self._raw_post_data

    def _get_method(self):

        return self.META['REQUEST_METHOD'].upper()

    GET = property(_get_get, _set_get)

    POST = property(_get_post, _set_post)

    COOKIES = property(_get_cookies, _set_cookies)

    FILES = property(_get_files)

    META = property(_get_meta)

    REQUEST = property(_get_request)

    raw_post_data = property(_get_raw_post_data)

    method = property(_get_method)

class ModPythonHandler(BaseHandler):

    request_class = ModPythonRequest

    def __call__(self, req):

        # mod_python fakes the environ, and thus doesn't process SetEnv.  This fixes that

        os.environ.update(req.subprocess_env)

        # now that the environ works we can see the correct settings, so imports

        # that use settings now can work

        from django.conf import settings

        # if we need to set up middleware, now that settings works we can do it now.

        if self._request_middleware is None:

            self.load_middleware()

        set_script_prefix(req.get_options().get('django.root', ''))

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

        try:

            try:

                request = self.request_class(req)

            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:

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

        # Convert our custom HttpResponse object back into the mod_python req.

        req.content_type = response['Content-Type']

        for key, value in response.items():

            if key != 'content-type':

                req.headers_out[str(key)] = str(value)

        for c in response.cookies.values():

            req.headers_out.add('Set-Cookie', c.output(header=''))

        req.status = response.status_code

        try:

            for chunk in response:

                req.write(chunk)

        finally:

            response.close()

        return 0 # mod_python.apache.OK

def handler(req):

    # mod_python hooks into this function.

    return ModPythonHandler()(req)