from rest_framework import generics, status
from rest_framework.decorators import api_view, permission_classes
from rest_framework.response import Response
from rest_framework.permissions import IsAuthenticated, AllowAny
from django.utils import timezone
from datetime import datetime, timedelta
from .models import AdminWeeklyAvailability, AppointmentRequest
from .serializers import (
    AdminWeeklyAvailabilitySerializer,
    AppointmentRequestSerializer,
    AppointmentRequestCreateSerializer,
    AppointmentScheduleSerializer,
    AppointmentRejectSerializer
)
from .email_service import EmailService
from users.models import CustomUser

class AdminAvailabilityView(generics.RetrieveUpdateAPIView):
    permission_classes = [IsAuthenticated]
    serializer_class = AdminWeeklyAvailabilitySerializer
    
    def get_object(self):
        obj, created = AdminWeeklyAvailability.objects.get_or_create(
            defaults={'available_days': []}
        )
        return obj

class AppointmentRequestListView(generics.ListAPIView):
    serializer_class = AppointmentRequestSerializer
    permission_classes = [IsAuthenticated]
    
    def get_queryset(self):
        queryset = AppointmentRequest.objects.all()
        
        if self.request.user.is_staff:
            return queryset
            
        return queryset.filter(email=self.request.user.email)

class AppointmentRequestCreateView(generics.CreateAPIView):
    permission_classes = [IsAuthenticated]
    queryset = AppointmentRequest.objects.all()
    serializer_class = AppointmentRequestCreateSerializer
    
    def perform_create(self, serializer):
        availability = AdminWeeklyAvailability.objects.first()
        if availability:
            available_days = availability.available_days
            preferred_dates = serializer.validated_data['preferred_dates']
            
            for date_str in preferred_dates:
                date_obj = datetime.strptime(date_str, '%Y-%m-%d').date()
                if date_obj.weekday() not in available_days:
                    from rest_framework.exceptions import ValidationError
                    raise ValidationError(f'Date {date_str} is not available for appointments.')
        
        appointment = serializer.save()
        EmailService.send_admin_notification(appointment)

class AppointmentRequestDetailView(generics.RetrieveAPIView):
    permission_classes = [IsAuthenticated]
    queryset = AppointmentRequest.objects.all()
    serializer_class = AppointmentRequestSerializer
    lookup_field = 'pk'

@api_view(['POST'])
@permission_classes([IsAuthenticated])
def schedule_appointment(request, pk):
    try:
        appointment = AppointmentRequest.objects.get(pk=pk)
    except AppointmentRequest.DoesNotExist:
        return Response({'error': 'Appointment not found'}, status=status.HTTP_404_NOT_FOUND)
    
    if appointment.status != 'pending_review':
        return Response(
            {'error': 'Only pending review appointments can be scheduled.'},
            status=status.HTTP_400_BAD_REQUEST
        )
    
    serializer = AppointmentScheduleSerializer(data=request.data)
    if serializer.is_valid():
        appointment.schedule_appointment(
            datetime_obj=serializer.validated_data['scheduled_datetime'],
            duration=serializer.validated_data['scheduled_duration']
        )
        
        EmailService.send_appointment_scheduled(appointment)
        
        response_serializer = AppointmentRequestSerializer(appointment)
        return Response({
            **response_serializer.data,
            'message': 'Appointment scheduled successfully. Jitsi meeting created.',
            'jitsi_meeting_created': appointment.has_jitsi_meeting
        })
    
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


@api_view(['POST'])
@permission_classes([IsAuthenticated])
def reject_appointment(request, pk):
    try:
        appointment = AppointmentRequest.objects.get(pk=pk)
    except AppointmentRequest.DoesNotExist:
        return Response({'error': 'Appointment not found'}, status=status.HTTP_404_NOT_FOUND)
    
    if appointment.status != 'pending_review':
        return Response(
            {'error': 'Only pending appointments can be rejected'}, 
            status=status.HTTP_400_BAD_REQUEST
        )
    
    serializer = AppointmentRejectSerializer(data=request.data)
    if serializer.is_valid():
        appointment.reject_appointment(serializer.validated_data.get('rejection_reason', ''))
        EmailService.send_appointment_rejected(appointment)
        return Response(AppointmentRequestSerializer(appointment).data)
    
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

@api_view(['GET'])
@permission_classes([AllowAny])
def available_dates(request):
    availability = AdminWeeklyAvailability.objects.first()
    if not availability:
        return Response([])
    
    available_days = availability.available_days
    today = timezone.now().date()
    available_dates = []
    
    for i in range(1, 31):
        date = today + timedelta(days=i)
        if date.weekday() in available_days:
            available_dates.append(date.strftime('%Y-%m-%d'))
    
    return Response(available_dates)

@api_view(['GET'])
@permission_classes([IsAuthenticated])
def user_appointments(request):
    appointments = AppointmentRequest.objects.filter(
        email=request.user.email
    ).order_by('-created_at')
    
    serializer = AppointmentRequestSerializer(appointments, many=True)
    return Response(serializer.data)

@api_view(['GET'])
@permission_classes([IsAuthenticated])
def appointment_stats(request):
    if not request.user.is_staff:
        return Response(
            {'error': 'Unauthorized'}, 
            status=status.HTTP_403_FORBIDDEN
        )
    
    total = AppointmentRequest.objects.count()
    users = CustomUser.objects.filter(is_staff=False).count()
    pending = AppointmentRequest.objects.filter(status='pending_review').count()
    scheduled = AppointmentRequest.objects.filter(status='scheduled').count()
    rejected = AppointmentRequest.objects.filter(status='rejected').count()
    
    return Response({
        'total_requests': total,
        'pending_review': pending,
        'scheduled': scheduled,
        'rejected': rejected,
        'users': users,
        'completion_rate': round((scheduled / total * 100), 2) if total > 0 else 0
    })

@api_view(['GET'])
@permission_classes([IsAuthenticated])
def user_apointment_stats(request):
    if not request.user.is_staff:
        return Response(
            {'error': 'Unauthorized'}, 
            status=status.HTTP_403_FORBIDDEN
        )
    
    total = AppointmentRequest.objects.filter(email=request.user.email).count()
    pending = AppointmentRequest.objects.filter(email=request.user.email, status='pending_review').count()
    scheduled = AppointmentRequest.objects.filter(email=request.user.email, status='scheduled').count()
    rejected = AppointmentRequest.objects.filter(email=request.user.email, status='rejected').count()
    completed = AppointmentRequest.objects.filter(email=request.user.email, status='completed').count()
    
    return Response({
        'total_requests': total,
        'pending_review': pending,
        'scheduled': scheduled,
        'rejected': rejected,
        'completed': completed,
        'completion_rate': round((scheduled / total * 100), 2) if total > 0 else 0
    })