from rest_framework.decorators import detail_route
from rest_framework.response import Response
from rest_framework.settings import api_settings
from rest_framework.views import APIView
from rest_framework.viewsets import ModelViewSet

from django.conf import settings
from django.contrib.contenttypes.models import ContentType
from django.http import Http404
from django.shortcuts import get_object_or_404

from dcim.models import (
    ConsolePort, ConsolePortTemplate, ConsoleServerPort, ConsoleServerPortTemplate, Device, DeviceBay,
    DeviceBayTemplate, DeviceRole, DeviceType, Interface, InterfaceConnection, InterfaceTemplate, Manufacturer, Module,
    Platform, PowerOutlet, PowerOutletTemplate, PowerPort, PowerPortTemplate, Rack, RackGroup, RackReservation,
    RackRole, Region, Site,
)
from dcim import filters
from extras.api.renderers import BINDZoneRenderer, FlatJSONRenderer
from extras.api.serializers import GraphSerializer
from extras.api.views import CustomFieldModelViewSet
from extras.models import Graph, GRAPH_TYPE_INTERFACE, GRAPH_TYPE_SITE
from utilities.api import ServiceUnavailable, WritableSerializerMixin
from .exceptions import MissingFilterException
from . import serializers


#
# Regions
#

class RegionViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = Region.objects.all()
    serializer_class = serializers.RegionSerializer
    write_serializer_class = serializers.WritableRegionSerializer


#
# Sites
#

class SiteViewSet(WritableSerializerMixin, CustomFieldModelViewSet):
    queryset = Site.objects.select_related('region', 'tenant')
    serializer_class = serializers.SiteSerializer
    filter_class = filters.SiteFilter
    write_serializer_class = serializers.WritableSiteSerializer

    @detail_route()
    def graphs(self, request, pk=None):
        site = get_object_or_404(Site, pk=pk)
        queryset = Graph.objects.filter(type=GRAPH_TYPE_SITE)
        serializer = GraphSerializer(queryset, many=True, context={'graphed_object': site})
        return Response(serializer.data)


#
# Rack groups
#

class RackGroupViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = RackGroup.objects.select_related('site')
    serializer_class = serializers.RackGroupSerializer
    filter_class = filters.RackGroupFilter
    write_serializer_class = serializers.WritableRackGroupSerializer


#
# Rack roles
#

class RackRoleViewSet(ModelViewSet):
    queryset = RackRole.objects.all()
    serializer_class = serializers.RackRoleSerializer


#
# Racks
#

class RackViewSet(WritableSerializerMixin, CustomFieldModelViewSet):
    queryset = Rack.objects.select_related('site', 'group__site', 'tenant')
    serializer_class = serializers.RackSerializer
    write_serializer_class = serializers.WritableRackSerializer
    filter_class = filters.RackFilter

    @detail_route(url_path='rack-units')
    def rack_units(self, request, pk=None):
        """
        List rack units (by rack)
        """
        rack = get_object_or_404(Rack, pk=pk)
        face = request.GET.get('face', 0)
        exclude_pk = request.GET.get('exclude', None)
        if exclude_pk is not None:
            try:
                exclude_pk = int(exclude_pk)
            except ValueError:
                exclude_pk = None
        elevation = rack.get_rack_units(face, exclude_pk)

        # Serialize Devices within the rack elevation
        for u in elevation:
            if u['device']:
                u['device'] = serializers.NestedDeviceSerializer(
                    instance=u['device'],
                    context={'request': request},
                ).data

        return Response(elevation)


#
# Rack reservations
#

class RackReservationViewSet(ModelViewSet):
    queryset = RackReservation.objects.all()
    serializer_class = serializers.RackReservationSerializer
    filter_class = filters.RackReservationFilter


#
# Manufacturers
#

class ManufacturerViewSet(ModelViewSet):
    queryset = Manufacturer.objects.all()
    serializer_class = serializers.ManufacturerSerializer


#
# Device types
#

class DeviceTypeViewSet(WritableSerializerMixin, CustomFieldModelViewSet):
    queryset = DeviceType.objects.select_related('manufacturer')
    serializer_class = serializers.DeviceTypeSerializer
    write_serializer_class = serializers.WritableDeviceTypeSerializer


#
# Device type components
#

class ConsolePortTemplateViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = ConsolePortTemplate.objects.select_related('device_type__manufacturer')
    serializer_class = serializers.ConsolePortTemplateSerializer
    write_serializer_class = serializers.WritableConsolePortTemplateSerializer
    filter_class = filters.ConsolePortTemplateFilter


class ConsoleServerPortTemplateViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = ConsoleServerPortTemplate.objects.select_related('device_type__manufacturer')
    serializer_class = serializers.ConsoleServerPortTemplateSerializer
    write_serializer_class = serializers.WritableConsoleServerPortTemplateSerializer
    filter_class = filters.ConsoleServerPortTemplateFilter


class PowerPortTemplateViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = PowerPortTemplate.objects.select_related('device_type__manufacturer')
    serializer_class = serializers.PowerPortTemplateSerializer
    write_serializer_class = serializers.WritablePowerPortTemplateSerializer
    filter_class = filters.PowerPortTemplateFilter


class PowerOutletTemplateViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = PowerOutletTemplate.objects.select_related('device_type__manufacturer')
    serializer_class = serializers.PowerOutletTemplateSerializer
    write_serializer_class = serializers.WritablePowerOutletTemplateSerializer
    filter_class = filters.PowerOutletTemplateFilter


class InterfaceTemplateViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = InterfaceTemplate.objects.select_related('device_type__manufacturer')
    serializer_class = serializers.InterfaceTemplateSerializer
    write_serializer_class = serializers.WritableInterfaceTemplateSerializer
    filter_class = filters.InterfaceTemplateFilter


class DeviceBayTemplateViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = DeviceBayTemplate.objects.select_related('device_type__manufacturer')
    serializer_class = serializers.DeviceBayTemplateSerializer
    write_serializer_class = serializers.WritableDeviceBayTemplateSerializer
    filter_class = filters.DeviceBayTemplateFilter


#
# Device roles
#

class DeviceRoleViewSet(ModelViewSet):
    queryset = DeviceRole.objects.all()
    serializer_class = serializers.DeviceRoleSerializer


#
# Platforms
#

class PlatformViewSet(ModelViewSet):
    queryset = Platform.objects.all()
    serializer_class = serializers.PlatformSerializer


#
# Devices
#

class DeviceViewSet(WritableSerializerMixin, CustomFieldModelViewSet):
    queryset = Device.objects.select_related(
        'device_type__manufacturer', 'device_role', 'tenant', 'platform', 'site', 'rack', 'parent_bay',
    ).prefetch_related(
        'primary_ip4__nat_outside', 'primary_ip6__nat_outside',
    )
    serializer_class = serializers.DeviceSerializer
    write_serializer_class = serializers.WritableDeviceSerializer
    filter_class = filters.DeviceFilter
    renderer_classes = api_settings.DEFAULT_RENDERER_CLASSES + [BINDZoneRenderer, FlatJSONRenderer]

    @detail_route(url_path='lldp-neighbors')
    def lldp_neighbors(self, request, pk):
        """
        Retrieve live LLDP neighbors of a device
        """
        device = get_object_or_404(Device, pk=pk)
        if not device.primary_ip:
            raise ServiceUnavailable("No IP configured for this device.")

        RPC = device.get_rpc_client()
        if not RPC:
            raise ServiceUnavailable("No RPC client available for this platform ({}).".format(device.platform))

        # Connect to device and retrieve inventory info
        try:
            with RPC(device, username=settings.NETBOX_USERNAME, password=settings.NETBOX_PASSWORD) as rpc_client:
                lldp_neighbors = rpc_client.get_lldp_neighbors()
        except:
            raise ServiceUnavailable("Error connecting to the remote device.")

        return Response(lldp_neighbors)


#
# Device components
#

class ConsolePortViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = ConsolePort.objects.select_related('device', 'cs_port__device')
    serializer_class = serializers.ConsolePortSerializer
    write_serializer_class = serializers.WritableConsolePortSerializer
    filter_class = filters.ConsolePortFilter


class ConsoleServerPortViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = ConsoleServerPort.objects.select_related('device', 'connected_console__device')
    serializer_class = serializers.ConsoleServerPortSerializer
    write_serializer_class = serializers.WritableConsoleServerPortSerializer
    filter_class = filters.ConsoleServerPortFilter


class PowerPortViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = PowerPort.objects.select_related('device', 'power_outlet__device')
    serializer_class = serializers.PowerPortSerializer
    write_serializer_class = serializers.WritablePowerPortSerializer
    filter_class = filters.PowerPortFilter


class PowerOutletViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = PowerOutlet.objects.select_related('device', 'connected_port__device')
    serializer_class = serializers.PowerOutletSerializer
    write_serializer_class = serializers.WritablePowerOutletSerializer
    filter_class = filters.PowerOutletFilter


class InterfaceViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = Interface.objects.select_related('device')
    serializer_class = serializers.InterfaceSerializer
    write_serializer_class = serializers.WritableInterfaceSerializer
    filter_class = filters.InterfaceFilter

    @detail_route()
    def graphs(self, request, pk=None):
        interface = get_object_or_404(Interface, pk=pk)
        queryset = Graph.objects.filter(type=GRAPH_TYPE_INTERFACE)
        serializer = GraphSerializer(queryset, many=True, context={'graphed_object': interface})
        return Response(serializer.data)


class DeviceBayViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = DeviceBay.objects.select_related('installed_device')
    serializer_class = serializers.DeviceBaySerializer
    write_serializer_class = serializers.WritableDeviceBaySerializer
    filter_class = filters.DeviceBayFilter


class ModuleViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = Module.objects.select_related('device', 'manufacturer')
    serializer_class = serializers.ModuleSerializer
    write_serializer_class = serializers.WritableModuleSerializer
    filter_class = filters.ModuleFilter


#
# Interface connections
#

class InterfaceConnectionViewSet(WritableSerializerMixin, ModelViewSet):
    queryset = InterfaceConnection.objects.select_related('interface_a__device', 'interface_b__device')
    serializer_class = serializers.InterfaceConnectionSerializer
    write_serializer_class = serializers.WritableInterfaceConnectionSerializer


#
# Miscellaneous
#

class RelatedConnectionsView(APIView):
    """
    Retrieve all connections related to a given console/power/interface connection
    """

    def __init__(self):
        super(RelatedConnectionsView, self).__init__()

        # Custom fields
        content_type = ContentType.objects.get_for_model(Device)
        custom_fields = content_type.custom_fields.prefetch_related('choices')

        # Cache all relevant CustomFieldChoices. This saves us from having to do a lookup per select field per object.
        custom_field_choices = {}
        for field in custom_fields:
            for cfc in field.choices.all():
                custom_field_choices[cfc.id] = cfc.value

        self.context = {
            'custom_fields': custom_fields,
            'custom_field_choices': custom_field_choices,
        }

    def get(self, request):

        peer_device = request.GET.get('peer-device')
        peer_interface = request.GET.get('peer-interface')

        # Search by interface
        if peer_device and peer_interface:

            # Determine local interface from peer interface's connection
            try:
                peer_iface = Interface.objects.get(device__name=peer_device, name=peer_interface)
            except Interface.DoesNotExist:
                raise Http404()
            local_iface = peer_iface.connected_interface
            if local_iface:
                device = local_iface.device
            else:
                return Response()

        else:
            raise MissingFilterException(detail='Must specify search parameters "peer-device" and "peer-interface".')

        # Initialize response skeleton
        response = {
            'device': serializers.DeviceSerializer(device, context=self.context).data,
            'console-ports': [],
            'power-ports': [],
            'interfaces': [],
        }

        # Console connections
        console_ports = ConsolePort.objects.filter(device=device).select_related('cs_port__device')
        for cp in console_ports:
            data = serializers.ConsolePortSerializer(instance=cp).data
            del(data['device'])
            response['console-ports'].append(data)

        # Power connections
        power_ports = PowerPort.objects.filter(device=device).select_related('power_outlet__device')
        for pp in power_ports:
            data = serializers.PowerPortSerializer(instance=pp).data
            del(data['device'])
            response['power-ports'].append(data)

        # Interface connections
        interfaces = Interface.objects.order_naturally(device.device_type.interface_ordering).filter(device=device)\
            .select_related('connected_as_a', 'connected_as_b', 'circuit_termination')
        for iface in interfaces:
            data = serializers.InterfaceSerializer(instance=iface).data
            del(data['device'])
            response['interfaces'].append(data)

        return Response(response)