# https://gist.github.com/bryanchow/6917ddc1823c09b5cc9f

import re
from django.http import HttpResponseRedirect
from django.conf import settings


SHOULD_REDIRECT_SSL = getattr(
    settings, 'SHOULD_REDIRECT_SSL', not settings.DEBUG
)
SSL_URLS = getattr(settings, 'SSL_URLS', [])
SSL_IGNORE_URLS = getattr(settings, 'SSL_IGNORE_URLS', [])


class SSLRedirectMiddleware:

    secure_urls = tuple([re.compile(url) for url in SSL_URLS])
    ignore_urls = tuple([re.compile(url) for url in SSL_IGNORE_URLS])

    def process_request(self, request):
        if not SHOULD_REDIRECT_SSL:
            return
        secure = False
        ignore = False
        for url in self.ignore_urls:
            if url.match(request.path):
                ignore = True
                break
        if not ignore:
            for url in self.secure_urls:
                if url.match(request.path):
                    secure = True
                    break
            if not secure == self._is_secure(request):
                return self._redirect(request, secure)

    def _is_secure(self, request):
        if request.is_secure():
            return True
        return False

    def _redirect(self, request, secure):
        protocol = secure and "https" or "http"
        if secure:
            host = getattr(settings, 'SSL_HOST', request.get_host())
        else:
            host = getattr(settings, 'HTTP_HOST', request.get_host())
        new_url = "%s://%s%s" % (protocol, host, request.get_full_path())
        if settings.DEBUG and request.method == 'POST':
            raise RuntimeError, (
                "Django can't perform a SSL redirect while maintaining POST "
                "data. Please structure your views so that redirects only "
                "occur during GETs."
            )
        return HttpResponseRedirect(new_url)