import logging

from django.urls import re_path
from django.contrib.auth.decorators import permission_required
from rest_framework import routers, viewsets, serializers, status
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from asgiref.sync import async_to_sync
from channels.layers import get_channel_layer

from core.settings import MAIL_DOMAIN
from mail.models import Email
from mail.protocol import send_smtp, make_reply, collect_references
from notify_sessions.models import SystemEvent
from tickets.models import IssueThread, Comment, STATE_CHOICES, StateChange


class IssueSerializer(serializers.ModelSerializer):
    timeline = serializers.SerializerMethodField()

    class Meta:
        model = IssueThread
        fields = ('id', 'timeline', 'name', 'state', 'assigned_to', 'last_activity')
        read_only_fields = ('id', 'timeline', 'last_activity')

    @staticmethod
    def get_timeline(obj):
        timeline = []
        for comment in obj.comments.all():
            timeline.append({
                'type': 'comment',
                'id': comment.id,
                'timestamp': comment.timestamp,
                'comment': comment.comment,
            })
        for state_change in obj.state_changes.all():
            timeline.append({
                'type': 'state',
                'id': state_change.id,
                'timestamp': state_change.timestamp,
                'state': state_change.state,
            })
        for email in obj.emails.all():
            timeline.append({
                'type': 'mail',
                'id': email.id,
                'timestamp': email.timestamp,
                'sender': email.sender,
                'recipient': email.recipient,
                'subject': email.subject,
                'body': email.body,
            })
        return sorted(timeline, key=lambda x: x['timestamp'])

    def update(self, instance, validated_data):
        if 'state' in validated_data:
            instance.state = validated_data['state']
            instance.save()
            StateChange.objects.create(
                issue_thread=instance,
                state=validated_data['state'],
            )
        return instance


class IssueViewSet(viewsets.ModelViewSet):
    serializer_class = IssueSerializer
    queryset = IssueThread.objects.all()


class CommentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Comment
        fields = ('id', 'comment', 'timestamp', 'issue_thread')


class CommentViewSet(viewsets.ModelViewSet):
    serializer_class = CommentSerializer
    queryset = Comment.objects.all()


@api_view(['POST'])
@permission_classes([IsAuthenticated])
@permission_required('tickets.add_issuethread', raise_exception=True)
def reply(request, pk):
    issue = IssueThread.objects.get(pk=pk)
    # email = issue.reply(request.data['body']) # TODO evaluate if this is a useful abstraction
    references = collect_references(issue)
    most_recent = Email.objects.filter(issue_thread=issue, recipient__endswith='@' + MAIL_DOMAIN).order_by(
        '-timestamp').first()
    mail = Email.objects.create(
        issue_thread=issue,
        sender=most_recent.recipient,
        recipient=most_recent.sender,
        subject=f'Re: {most_recent.subject}',
        body=request.data['message'],
        in_reply_to=most_recent.reference,
    )
    log = logging.getLogger('mail.log')
    async_to_sync(send_smtp)(make_reply(mail, references), log)

    return Response({'status': 'ok'}, status=status.HTTP_201_CREATED)


@api_view(['POST'])
@permission_classes([IsAuthenticated])
@permission_required('tickets.add_issuethread_manual', raise_exception=True)
def manual_ticket(request):
    if 'name' not in request.data:
        return Response({'status': 'error', 'message': 'missing name'}, status=status.HTTP_400_BAD_REQUEST)
    if 'sender' not in request.data:
        return Response({'status': 'error', 'message': 'missing sender'}, status=status.HTTP_400_BAD_REQUEST)
    if 'recipient' not in request.data:
        return Response({'status': 'error', 'message': 'missing recipient'}, status=status.HTTP_400_BAD_REQUEST)
    if 'body' not in request.data:
        return Response({'status': 'error', 'message': 'missing body'}, status=status.HTTP_400_BAD_REQUEST)

    issue = IssueThread.objects.create(
        name=request.data['name'],
        manually_created=True,
    )
    email = Email.objects.create(
        issue_thread=issue,
        sender=request.data['sender'],
        recipient=request.data['recipient'],
        subject=request.data['name'],
        body=request.data['body'],
    )
    systemevent = SystemEvent.objects.create(type='email received', reference=email.id)
    channel_layer = get_channel_layer()
    async_to_sync(channel_layer.group_send)(
        'general', {"type": "generic.event", "name": "send_message_to_frontend", "event_id": systemevent.id,
                    "message": "email received"}
    )

    return Response(IssueSerializer(issue).data, status=status.HTTP_201_CREATED)


class StateSerializer(serializers.Serializer):
    text = serializers.SerializerMethodField()
    value = serializers.SerializerMethodField()

    def get_text(self, obj):
        return obj['text']

    def get_value(self, obj):
        return obj['value']


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def get_available_states(request):
    def get_state_choices():
        for state in STATE_CHOICES:
            yield {'value': list(state)[0], 'text': list(state)[1]}
    return Response(get_state_choices())


router = routers.SimpleRouter()
router.register(r'tickets', IssueViewSet, basename='issues')
router.register(r'comments', CommentViewSet, basename='comments')

urlpatterns = ([
                   re_path(r'^tickets/(?P<pk>\d+)/reply/$', reply, name='reply'),
                   re_path(r'^tickets/manual/$', manual_ticket, name='manual_ticket'),
                   re_path(r'^tickets/states/$', get_available_states, name='get_available_states'),
               ] + router.urls)