import hashlib
import json
import os
import re
import socket

import mimetypes
from django.conf import settings
from django.contrib import messages
from django.contrib.auth import logout as do_logout
from django.contrib.auth import get_user_model
from django.contrib.gis.measure import D
from django.core.paginator import EmptyPage, PageNotAnInteger, Paginator
from django.core.signing import BadSignature, Signer
from django.core.validators import URLValidator, ValidationError
from django.db.models import Q
from django.http import (HttpResponse, HttpResponseBadRequest,
                         HttpResponseForbidden, HttpResponsePermanentRedirect,
                         HttpResponseRedirect)
from django.middleware.gzip import re_accepts_gzip
from django.shortcuts import get_object_or_404
from django.template.loader import render_to_string
from django.urls import reverse, reverse_lazy
from django.utils.encoding import force_bytes, smart_bytes
from django.utils.http import http_date
from django.utils.translation import ugettext as _
from django.utils.translation import to_locale
from django.views.generic import DetailView, TemplateView, View
from django.views.generic.base import RedirectView
from django.views.generic.detail import BaseDetailView
from django.views.generic.edit import CreateView, DeleteView, UpdateView
from django.views.generic.list import ListView

from .forms import (DEFAULT_LATITUDE, DEFAULT_LONGITUDE, DEFAULT_CENTER,
                    AnonymousMapPermissionsForm, DataLayerForm, FlatErrorList,
                    MapSettingsForm, UpdateMapPermissionsForm)
from .models import DataLayer, Licence, Map, Pictogram, TileLayer
from .utils import get_uri_template, gzip_file

try:
    # python3
    from urllib.parse import urlparse
    from urllib.request import Request, build_opener
    from urllib.error import HTTPError
except ImportError:
    from urlparse import urlparse
    from urllib2 import Request, HTTPError, build_opener


User = get_user_model()


PRIVATE_IP = re.compile(r'((^127\.)|(^10\.)'
                        r'|(^172\.1[6-9]\.)'
                        r'|(^172\.2[0-9]\.)'
                        r'|(^172\.3[0-1]\.)'
                        r'|(^192\.168\.))')
ANONYMOUS_COOKIE_MAX_AGE = 60 * 60 * 24 * 30  # One month


class PaginatorMixin(object):
    per_page = 5

    def paginate(self, qs, per_page=None):
        paginator = Paginator(qs, per_page or self.per_page)
        page = self.request.GET.get('p')
        try:
            qs = paginator.page(page)
        except PageNotAnInteger:
            # If page is not an integer, deliver first page.
            qs = paginator.page(1)
        except EmptyPage:
            # If page is out of range (e.g. 9999), deliver last page of
            # results.
            qs = paginator.page(paginator.num_pages)
        return qs


class Home(TemplateView, PaginatorMixin):
    template_name = "umap/home.html"
    list_template_name = "umap/map_list.html"

    def get_context_data(self, **kwargs):
        qs = Map.public
        if (settings.UMAP_EXCLUDE_DEFAULT_MAPS and
            'spatialite' not in settings.DATABASES['default']['ENGINE']):
                # Unsupported query type for sqlite.
            qs = qs.filter(center__distance_gt=(DEFAULT_CENTER, D(km=1)))
        demo_map = None
        if hasattr(settings, "UMAP_DEMO_PK"):
            try:
                demo_map = Map.public.get(pk=settings.UMAP_DEMO_PK)
            except Map.DoesNotExist:
                pass
            else:
                qs = qs.exclude(id=demo_map.pk)
        showcase_map = None
        if hasattr(settings, "UMAP_SHOWCASE_PK"):
            try:
                showcase_map = Map.public.get(pk=settings.UMAP_SHOWCASE_PK)
            except Map.DoesNotExist:
                pass
            else:
                qs = qs.exclude(id=showcase_map.pk)
        maps = qs.order_by('-modified_at')[:50]
        maps = self.paginate(maps, settings.UMAP_MAPS_PER_PAGE)

        return {
            "maps": maps,
            "demo_map": demo_map,
            "showcase_map": showcase_map,
            "DEMO_SITE": settings.UMAP_DEMO_SITE
        }

    def get_template_names(self):
        """
        Dispatch template according to the kind of request: ajax or normal.
        """
        if self.request.is_ajax():
            return [self.list_template_name]
        else:
            return [self.template_name]

home = Home.as_view()


class About(Home):

    template_name = "umap/about.html"

about = About.as_view()


class UserMaps(DetailView, PaginatorMixin):
    model = User
    slug_url_kwarg = 'username'
    slug_field = 'username'
    list_template_name = "umap/map_list.html"
    context_object_name = "current_user"

    def get_context_data(self, **kwargs):
        owner = self.request.user == self.object
        manager = Map.objects if owner else Map.public
        maps = manager.filter(Q(owner=self.object) | Q(editors=self.object))
        if owner:
            per_page = settings.UMAP_MAPS_PER_PAGE_OWNER
            limit = 100
        else:
            per_page = settings.UMAP_MAPS_PER_PAGE
            limit = 50
        maps = maps.distinct().order_by('-modified_at')[:limit]
        maps = self.paginate(maps, per_page)
        kwargs.update({
            "maps": maps
        })
        return super(UserMaps, self).get_context_data(**kwargs)

    def get_template_names(self):
        """
        Dispatch template according to the kind of request: ajax or normal.
        """
        if self.request.is_ajax():
            return [self.list_template_name]
        else:
            return super(UserMaps, self).get_template_names()

user_maps = UserMaps.as_view()


class Search(TemplateView, PaginatorMixin):
    template_name = "umap/search.html"
    list_template_name = "umap/map_list.html"

    def get_context_data(self, **kwargs):
        q = self.request.GET.get('q')
        results = []
        if q:
            where = "to_tsvector(name) @@ plainto_tsquery(%s)"
            if getattr(settings, 'UMAP_USE_UNACCENT', False):
                where = "to_tsvector(unaccent(name)) @@ plainto_tsquery(unaccent(%s))"  # noqa
            results = Map.objects.filter(share_status=Map.PUBLIC)
            results = results.extra(where=[where], params=[q])
            results = results.order_by('-modified_at')
            results = self.paginate(results)
        kwargs.update({
            'maps': results,
            'q': q
        })
        return kwargs

    def get_template_names(self):
        """
        Dispatch template according to the kind of request: ajax or normal.
        """
        if self.request.is_ajax():
            return [self.list_template_name]
        else:
            return super(Search, self).get_template_names()

search = Search.as_view()


class MapsShowCase(View):

    def get(self, *args, **kwargs):
        maps = Map.public.filter(center__distance_gt=(DEFAULT_CENTER, D(km=1)))
        maps = maps.order_by('-modified_at')[:2500]

        def make(m):
            description = m.description or ""
            if m.owner:
                description = u"{description}\n{by} [[{url}|{name}]]".format(
                    description=description,
                    by=_("by"),
                    url=reverse('user_maps',
                                kwargs={"username": m.owner.username}),
                    name=m.owner,
                )
            description = u"{}\n[[{}|{}]]".format(
                description, m.get_absolute_url(), _("View the map"))
            geometry = m.settings.get('geometry', json.loads(m.center.geojson))
            return {
                "type": "Feature",
                "geometry": geometry,
                "properties": {
                    "name": m.name,
                    "description": description
                }
            }

        geojson = {
            "type": "FeatureCollection",
            "features": [make(m) for m in maps]
        }
        return HttpResponse(smart_bytes(json.dumps(geojson)))

showcase = MapsShowCase.as_view()


def validate_url(request):
    assert request.method == "GET"
    assert request.is_ajax()
    url = request.GET.get('url')
    assert url
    try:
        URLValidator(url)
    except ValidationError:
        raise AssertionError()
    assert 'HTTP_REFERER' in request.META
    referer = urlparse(request.META.get('HTTP_REFERER'))
    toproxy = urlparse(url)
    local = urlparse(settings.SITE_URL)
    assert toproxy.hostname
    assert referer.hostname == local.hostname
    assert toproxy.hostname != "localhost"
    assert toproxy.netloc != local.netloc
    try:
        # clean this when in python 3.4
        ipaddress = socket.gethostbyname(toproxy.hostname)
    except:
        raise AssertionError()
    assert not PRIVATE_IP.match(ipaddress)
    return url


class AjaxProxy(View):

    def get(self, *args, **kwargs):
        # You should not use this in production (use Nginx or so)
        try:
            url = validate_url(self.request)
        except AssertionError:
            return HttpResponseBadRequest()
        headers = {
            'User-Agent': 'uMapProxy +http://wiki.openstreetmap.org/wiki/UMap'
        }
        request = Request(url, headers=headers)
        opener = build_opener()
        try:
            proxied_request = opener.open(request)
        except HTTPError as e:
            return HttpResponse(e.msg, status=e.code,
                                content_type='text/plain')
        else:
            status_code = proxied_request.code
            mimetype = proxied_request.headers.get('Content-Type') or mimetypes.guess_type(url)  # noqa
            content = proxied_request.read()
            # Quick hack to prevent Django from adding a Vary: Cookie header
            self.request.session.accessed = False
            response = HttpResponse(content, status=status_code,
                                    content_type=mimetype)
            try:
                ttl = int(self.request.GET.get('ttl'))
            except (TypeError, ValueError):
                pass
            else:
                response['X-Accel-Expires'] = ttl
            return response
ajax_proxy = AjaxProxy.as_view()


# ############## #
#     Utils      #
# ############## #

def _urls_for_js(urls=None):
    """
    Return templated URLs prepared for javascript.
    """
    if urls is None:
        # prevent circular import
        from .urls import urlpatterns, i18n_urls
        urls = [url.name for url in urlpatterns + i18n_urls
                if getattr(url, 'name', None)]
    urls = dict(zip(urls, [get_uri_template(url) for url in urls]))
    urls.update(getattr(settings, 'UMAP_EXTRA_URLS', {}))
    return urls


def render_to_json(templates, context, request):
    """
    Generate a JSON HttpResponse with rendered template HTML.
    """
    html = render_to_string(
        templates,
        context=context,
        request=request
    )
    _json = json.dumps({
        "html": html
    })
    return HttpResponse(_json)


def simple_json_response(**kwargs):
    return HttpResponse(json.dumps(kwargs))


# ############## #
#      Map       #
# ############## #


class FormLessEditMixin:
    http_method_names = [u'post', ]

    def form_invalid(self, form):
        return simple_json_response(errors=form.errors,
                                    error=str(form.errors))

    def get_form(self, form_class=None):
        kwargs = self.get_form_kwargs()
        kwargs['error_class'] = FlatErrorList
        return self.get_form_class()(**kwargs)


class MapDetailMixin:

    model = Map

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        properties = {
            'urls': _urls_for_js(),
            'tilelayers': TileLayer.get_list(),
            'allowEdit': self.is_edit_allowed(),
            'default_iconUrl': "%sumap/img/marker.png" % settings.STATIC_URL,  # noqa
            'umap_id': self.get_umap_id(),
            'licences': dict((l.name, l.json) for l in Licence.objects.all()),
            'edit_statuses': [(i, str(label)) for i, label in Map.EDIT_STATUS],
            'share_statuses': [(i, str(label))
                               for i, label in Map.SHARE_STATUS if i != Map.BLOCKED],
            'anonymous_edit_statuses': [(i, str(label)) for i, label
                                        in AnonymousMapPermissionsForm.STATUS],
        }
        if self.get_short_url():
            properties['shortUrl'] = self.get_short_url()

        if settings.USE_I18N:
            locale = settings.LANGUAGE_CODE
            # Check attr in case the middleware is not active
            if hasattr(self.request, "LANGUAGE_CODE"):
                locale = self.request.LANGUAGE_CODE
            locale = to_locale(locale)
            properties['locale'] = locale
            context['locale'] = locale
        user = self.request.user
        if not user.is_anonymous:
            properties['user'] = {
                'id': user.pk,
                'name': user.get_username(),
                'url': reverse(settings.USER_MAPS_URL,
                               args=(user.get_username(), ))
            }
        map_settings = self.get_geojson()
        if "properties" not in map_settings:
            map_settings['properties'] = {}
        map_settings['properties'].update(properties)
        map_settings['properties']['datalayers'] = self.get_datalayers()
        context['map_settings'] = json.dumps(map_settings,
                                             indent=settings.DEBUG)
        return context

    def get_datalayers(self):
        return []

    def is_edit_allowed(self):
        return True

    def get_umap_id(self):
        return None

    def get_geojson(self):
        return {
            "geometry": {
                "coordinates": [DEFAULT_LONGITUDE, DEFAULT_LATITUDE],
                "type": "Point"
            },
            "properties": {
                "zoom": getattr(settings, 'LEAFLET_ZOOM', 6),
                "datalayers": [],
            }
        }

    def get_short_url(self):
        return None


class PermissionsMixin:

    def get_permissions(self):
        permissions = {}
        permissions['edit_status'] = self.object.edit_status
        permissions['share_status'] = self.object.share_status
        if self.object.owner:
            permissions['owner'] = {
                'id': self.object.owner.pk,
                'name': self.object.owner.get_username(),
                'url': reverse(settings.USER_MAPS_URL,
                               args=(self.object.owner.get_username(), ))
            }
            permissions['editors'] = [{
                'id': editor.pk,
                'name': editor.get_username(),
            } for editor in self.object.editors.all()]
        if (not self.object.owner
           and self.object.is_anonymous_owner(self.request)):
            permissions['anonymous_edit_url'] = self.get_anonymous_edit_url()
        return permissions

    def get_anonymous_edit_url(self):
        anonymous_url = self.object.get_anonymous_edit_url()
        return settings.SITE_URL + anonymous_url


class MapView(MapDetailMixin, PermissionsMixin, DetailView):

    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        canonical = self.get_canonical_url()
        if not request.path == canonical:
            if request.META.get('QUERY_STRING'):
                canonical = "?".join([canonical, request.META['QUERY_STRING']])
            return HttpResponsePermanentRedirect(canonical)
        if not self.object.can_view(request):
            return HttpResponseForbidden()
        return super(MapView, self).get(request, *args, **kwargs)

    def get_canonical_url(self):
        return self.object.get_absolute_url()

    def get_datalayers(self):
        datalayers = DataLayer.objects.filter(map=self.object)
        return [l.metadata for l in datalayers]

    def is_edit_allowed(self):
        return self.object.can_edit(self.request.user, self.request)

    def get_umap_id(self):
        return self.object.pk

    def get_short_url(self):
        shortUrl = None
        if hasattr(settings, 'SHORT_SITE_URL'):
            short_path = reverse_lazy('map_short_url',
                                      kwargs={'pk': self.object.pk})
            shortUrl = "%s%s" % (settings.SHORT_SITE_URL, short_path)
        return shortUrl

    def get_geojson(self):
        map_settings = self.object.settings
        if "properties" not in map_settings:
            map_settings['properties'] = {}
        map_settings['properties']['name'] = self.object.name
        map_settings['properties']['permissions'] = self.get_permissions()
        return map_settings


class MapViewGeoJSON(MapView):

    def get_canonical_url(self):
        return reverse('map_geojson', args=(self.object.pk, ))

    def render_to_response(self, context, *args, **kwargs):
        return HttpResponse(context['map_settings'],
                            content_type='application/json')


class MapNew(MapDetailMixin, TemplateView):
    template_name = "umap/map_detail.html"


class MapCreate(FormLessEditMixin, PermissionsMixin, CreateView):
    model = Map
    form_class = MapSettingsForm

    def form_valid(self, form):
        if self.request.user.is_authenticated:
            form.instance.owner = self.request.user
        self.object = form.save()
        anonymous_url = self.get_anonymous_edit_url()
        if not self.request.user.is_authenticated:
            msg = _(
                "Your map has been created! If you want to edit this map from "
                "another computer, please use this link: %(anonymous_url)s"
                % {"anonymous_url": anonymous_url}
            )
        else:
            msg = _("Congratulations, your map has been created!")
        permissions = self.get_permissions()
        # User does not have the cookie yet.
        permissions['anonymous_edit_url'] = anonymous_url
        response = simple_json_response(
            id=self.object.pk,
            url=self.object.get_absolute_url(),
            permissions=permissions,
            info=msg
        )
        if not self.request.user.is_authenticated:
            key, value = self.object.signed_cookie_elements
            response.set_signed_cookie(
                key=key,
                value=value,
                max_age=ANONYMOUS_COOKIE_MAX_AGE
            )
        return response


class MapUpdate(FormLessEditMixin, PermissionsMixin, UpdateView):
    model = Map
    form_class = MapSettingsForm
    pk_url_kwarg = 'map_id'

    def form_valid(self, form):
        self.object.settings = form.cleaned_data["settings"]
        self.object.save()
        return simple_json_response(
            id=self.object.pk,
            url=self.object.get_absolute_url(),
            permissions=self.get_permissions(),
            info=_("Map has been updated!"),
        )


class UpdateMapPermissions(FormLessEditMixin, UpdateView):
    model = Map
    pk_url_kwarg = 'map_id'

    def get_form_class(self):
        if self.object.owner:
            return UpdateMapPermissionsForm
        else:
            return AnonymousMapPermissionsForm

    def get_form(self, form_class=None):
        form = super().get_form(form_class)
        user = self.request.user
        if self.object.owner and not user == self.object.owner:
            del form.fields['edit_status']
            del form.fields['share_status']
            del form.fields['owner']
        return form

    def form_valid(self, form):
        self.object = form.save()
        return simple_json_response(
            info=_("Map editors updated with success!"))


class AttachAnonymousMap(View):

    def post(self, *args, **kwargs):
        self.object = kwargs['map_inst']
        if (self.object.owner
           or not self.object.is_anonymous_owner(self.request)
           or not self.object.can_edit(self.request.user, self.request)
           or not self.request.user.is_authenticated):
            return HttpResponseForbidden()
        self.object.owner = self.request.user
        self.object.save()
        return simple_json_response()


class MapDelete(DeleteView):
    model = Map
    pk_url_kwarg = "map_id"

    def delete(self, *args, **kwargs):
        self.object = self.get_object()
        if self.object.owner and self.request.user != self.object.owner:
            return HttpResponseForbidden(
                _('Only its owner can delete the map.'))
        if not self.object.owner\
           and not self.object.is_anonymous_owner(self.request):
            return HttpResponseForbidden()
        self.object.delete()
        return simple_json_response(redirect="/")


class MapClone(PermissionsMixin, View):

    def post(self, *args, **kwargs):
        if not getattr(settings, "UMAP_ALLOW_ANONYMOUS", False) \
           and not self.request.user.is_authenticated:
            return HttpResponseForbidden()
        owner = self.request.user if self.request.user.is_authenticated else None
        self.object = kwargs['map_inst'].clone(owner=owner)
        response = simple_json_response(redirect=self.object.get_absolute_url())
        if not self.request.user.is_authenticated:
            key, value = self.object.signed_cookie_elements
            response.set_signed_cookie(
                key=key,
                value=value,
                max_age=ANONYMOUS_COOKIE_MAX_AGE
            )
            msg = _(
                "Your map has been cloned! If you want to edit this map from "
                "another computer, please use this link: %(anonymous_url)s"
                % {"anonymous_url": self.get_anonymous_edit_url()}
            )
        else:
            msg = _("Congratulations, your map has been cloned!")
        messages.info(self.request, msg)
        return response


class MapShortUrl(RedirectView):
    query_string = True
    permanent = True

    def get_redirect_url(self, **kwargs):
        map_inst = get_object_or_404(Map, pk=kwargs['pk'])
        url = map_inst.get_absolute_url()
        if self.query_string:
            args = self.request.META.get('QUERY_STRING', '')
            if args:
                url = "%s?%s" % (url, args)
        return url


class MapAnonymousEditUrl(RedirectView):

    permanent = False

    def get(self, request, *args, **kwargs):
        signer = Signer()
        try:
            pk = signer.unsign(self.kwargs['signature'])
        except BadSignature:
            return HttpResponseForbidden()
        else:
            map_inst = get_object_or_404(Map, pk=pk)
            url = map_inst.get_absolute_url()
            response = HttpResponseRedirect(url)
            if not map_inst.owner:
                key, value = map_inst.signed_cookie_elements
                response.set_signed_cookie(
                    key=key,
                    value=value,
                    max_age=ANONYMOUS_COOKIE_MAX_AGE
                )
            return response


# ############## #
#    DataLayer   #
# ############## #


class GZipMixin(object):

    EXT = '.gz'

    def _path(self):
        return self.object.geojson.path

    def path(self):
        """
        Serve gzip file if client accept it.
        Generate or update the gzip file if needed.
        """
        path = self._path()
        statobj = os.stat(path)
        ae = self.request.META.get('HTTP_ACCEPT_ENCODING', '')
        if re_accepts_gzip.search(ae) and getattr(settings, 'UMAP_GZIP', True):
            gzip_path = "{path}{ext}".format(path=path, ext=self.EXT)
            up_to_date = True
            if not os.path.exists(gzip_path):
                up_to_date = False
            else:
                gzip_statobj = os.stat(gzip_path)
                if statobj.st_mtime > gzip_statobj.st_mtime:
                    up_to_date = False
            if not up_to_date:
                gzip_file(path, gzip_path)
            path = gzip_path
        return path

    def etag(self):
        path = self.path()
        with open(path, mode='rb') as f:
            return hashlib.md5(f.read()).hexdigest()


class DataLayerView(GZipMixin, BaseDetailView):
    model = DataLayer

    def render_to_response(self, context, **response_kwargs):
        response = None
        path = self.path()

        if getattr(settings, 'UMAP_XSENDFILE_HEADER', None):
            response = HttpResponse()
            path = path.replace(settings.MEDIA_ROOT, '/internal')
            response[settings.UMAP_XSENDFILE_HEADER] = path
        else:
            # TODO IMS
            statobj = os.stat(path)
            with open(path, 'rb') as f:
                response = HttpResponse(
                    f.read(),  # should not be used in production!
                    content_type='application/json'
                )
            response["Last-Modified"] = http_date(statobj.st_mtime)
            response['ETag'] = '%s' % hashlib.md5(force_bytes(response.content)).hexdigest()  # noqa
            response['Content-Length'] = len(response.content)
        if path.endswith(self.EXT):
            response['Content-Encoding'] = 'gzip'
        return response


class DataLayerVersion(DataLayerView):

    def _path(self):
        return '{root}/{path}'.format(
            root=settings.MEDIA_ROOT,
            path=self.object.get_version_path(self.kwargs['name']))


class DataLayerCreate(FormLessEditMixin, GZipMixin, CreateView):
    model = DataLayer
    form_class = DataLayerForm

    def form_valid(self, form):
        form.instance.map = self.kwargs['map_inst']
        self.object = form.save()
        response = simple_json_response(**self.object.metadata)
        response['ETag'] = self.etag()
        return response


class DataLayerUpdate(FormLessEditMixin, GZipMixin, UpdateView):
    model = DataLayer
    form_class = DataLayerForm

    def form_valid(self, form):
        self.object = form.save()
        response = simple_json_response(**self.object.metadata)
        response['ETag'] = self.etag()
        return response

    def if_match(self):
        """Optimistic concurrency control."""
        match = True
        if_match = self.request.META.get('HTTP_IF_MATCH')
        if if_match:
            etag = self.etag()
            if etag != if_match:
                match = False
        return match

    def post(self, request, *args, **kwargs):
        self.object = self.get_object()
        if self.object.map != self.kwargs['map_inst']:
            return HttpResponseForbidden()
        if not self.if_match():
            return HttpResponse(status=412)
        return super(DataLayerUpdate, self).post(request, *args, **kwargs)


class DataLayerDelete(DeleteView):
    model = DataLayer

    def delete(self, *args, **kwargs):
        self.object = self.get_object()
        if self.object.map != self.kwargs['map_inst']:
            return HttpResponseForbidden()
        self.object.delete()
        return simple_json_response(info=_("Layer successfully deleted."))


class DataLayerVersions(BaseDetailView):
    model = DataLayer

    def render_to_response(self, context, **response_kwargs):
        return simple_json_response(versions=self.object.versions)


# ############## #
#     Picto      #
# ############## #

class PictogramJSONList(ListView):
    model = Pictogram

    def render_to_response(self, context, **response_kwargs):
        content = [p.json for p in Pictogram.objects.all()]
        return simple_json_response(pictogram_list=content)


# ############## #
#     Generic    #
# ############## #

def logout(request):
    do_logout(request)
    return simple_json_response(redirect="/")


class LoginPopupEnd(TemplateView):
    """
    End of a loggin process in popup.
    Basically close the popup.
    """
    template_name = "umap/login_popup_end.html"
