import mimetypes
import os
from collections import OrderedDict

from django.conf import settings
from django.core.files import File
from django.http import Http404, HttpResponse
from rest_framework.decorators import detail_route
from rest_framework.response import Response
from rest_framework.viewsets import ReadOnlyModelViewSet, ViewSet

from c3nav.access.apply import filter_arealocations_by_access, filter_queryset_by_access, get_unlocked_packages_names
from c3nav.mapdata.models import GEOMETRY_MAPITEM_TYPES, AreaLocation, Level, LocationGroup, Package, Source
from c3nav.mapdata.models.geometry import DirectedLineGeometryMapItemWithLevel
from c3nav.mapdata.search import get_location
from c3nav.mapdata.serializers.main import LevelSerializer, PackageSerializer, SourceSerializer
from c3nav.mapdata.utils.cache import (CachedReadOnlyViewSetMixin, cache_mapdata_api_response, get_levels_cached,
                                       get_packages_cached)


class GeometryTypeViewSet(ViewSet):
    """
    Lists all geometry types.
    """
    @cache_mapdata_api_response()
    def list(self, request):
        return Response([
            OrderedDict((
                ('name', name),
                ('title', str(mapitemtype._meta.verbose_name)),
                ('title_plural', str(mapitemtype._meta.verbose_name_plural)),
            )) for name, mapitemtype in GEOMETRY_MAPITEM_TYPES.items()
        ])


class GeometryViewSet(ViewSet):
    """
    List all geometries.
    You can filter by adding a level GET parameter or one or more package or type GET parameters.
    """
    def list(self, request):
        types = set(request.GET.getlist('type'))
        valid_types = list(GEOMETRY_MAPITEM_TYPES.keys())
        if not types:
            types = valid_types
        else:
            types = [t for t in valid_types if t in types]

        level = None
        if 'level' in request.GET:
            levels_cached = get_levels_cached()
            level_name = request.GET['level']
            if level_name in levels_cached:
                level = levels_cached[level_name]

        packages_cached = get_packages_cached()
        package_names = set(request.GET.getlist('package')) & set(get_unlocked_packages_names(request))
        packages = [packages_cached[name] for name in package_names if name in packages_cached]
        if len(packages) == len(packages_cached):
            packages = []
        package_ids = sorted([package.id for package in packages])

        cache_key = '__'.join((
            ','.join([str(i) for i in types]),
            str(level.id) if level is not None else '',
            ','.join([str(i) for i in package_ids]),
        ))

        return self._list(request, types=types, level=level, packages=packages, add_cache_key=cache_key)

    @staticmethod
    def compare_by_location_type(x: AreaLocation, y: AreaLocation):
        return AreaLocation.LOCATION_TYPES.index(x.location_type) - AreaLocation.LOCATION_TYPES.index(y.location_type)

    @cache_mapdata_api_response()
    def _list(self, request, types, level, packages):
        results = []
        for t in types:
            mapitemtype = GEOMETRY_MAPITEM_TYPES[t]
            queryset = mapitemtype.objects.all()
            if packages:
                queryset = queryset.filter(package__in=packages)
            if level:
                if hasattr(mapitemtype, 'level'):
                    queryset = queryset.filter(level=level)
                elif hasattr(mapitemtype, 'levels'):
                    queryset = queryset.filter(levels=level)
                else:
                    queryset = queryset.none()
            queryset = filter_queryset_by_access(request, queryset)
            queryset = queryset.order_by('name')

            for field_name in ('package', 'level', 'crop_to_level', 'elevator'):
                if hasattr(mapitemtype, field_name):
                    queryset = queryset.select_related(field_name)

            for field_name in ('levels', ):
                if hasattr(mapitemtype, field_name):
                    queryset.prefetch_related(field_name)

            if issubclass(mapitemtype, AreaLocation):
                queryset = sorted(queryset, key=AreaLocation.get_sort_key)

            if issubclass(mapitemtype, DirectedLineGeometryMapItemWithLevel):
                results.extend(obj.to_shadow_geojson() for obj in queryset)

            results.extend(obj.to_geojson() for obj in queryset)

        return Response(results)


class PackageViewSet(CachedReadOnlyViewSetMixin, ReadOnlyModelViewSet):
    """
    Retrieve packages the map consists of.
    """
    queryset = Package.objects.all()
    serializer_class = PackageSerializer
    lookup_field = 'name'
    lookup_value_regex = '[^/]+'
    ordering = ('name',)


class LevelViewSet(CachedReadOnlyViewSetMixin, ReadOnlyModelViewSet):
    """
    List and retrieve levels.
    """
    queryset = Level.objects.all()
    serializer_class = LevelSerializer
    lookup_field = 'name'
    lookup_value_regex = '[^/]+'
    ordering = ('altitude',)


class SourceViewSet(CachedReadOnlyViewSetMixin, ReadOnlyModelViewSet):
    """
    List and retrieve source images (to use as a drafts).
    """
    queryset = Source.objects.all()
    serializer_class = SourceSerializer
    lookup_field = 'name'
    lookup_value_regex = '[^/]+'
    ordering = ('name',)
    include_package_access = True

    def get_queryset(self):
        return filter_queryset_by_access(self.request, super().get_queryset().all())

    @detail_route(methods=['get'])
    def image(self, request, name=None):
        return self._image(request, name=name, add_cache_key=self._get_add_cache_key(request))

    @cache_mapdata_api_response()
    def _image(self, request, name=None):
        source = self.get_object()
        response = HttpResponse(content_type=mimetypes.guess_type(source.name)[0])
        image_path = os.path.join(settings.MAP_ROOT, source.package.directory, 'sources', source.name)
        for chunk in File(open(image_path, 'rb')).chunks():
            response.write(chunk)
        return response


class LocationViewSet(ViewSet):
    """
    List and retrieve locations
    """
    # We don't cache this, because it depends on access_list
    lookup_field = 'name'
    include_package_access = True

    def list(self, request, **kwargs):
        locations = []
        locations += list(filter_queryset_by_access(request, LocationGroup.objects.filter(can_search=True,
                                                                                          compiled_room=True)))
        locations += sorted(filter_arealocations_by_access(request, AreaLocation.objects.filter(can_search=True)),
                            key=AreaLocation.get_sort_key, reverse=True)
        locations += list(filter_queryset_by_access(request, LocationGroup.objects.filter(can_search=True,
                                                                                          compiled_room=False)))
        return Response([location.to_location_json() for location in locations])

    def retrieve(self, request, name=None, **kwargs):
        location = get_location(request, name)
        if location is None:
            raise Http404
        return Response(location.to_json())