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,IsAdminUser
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
from django.db.models import Count, Q


class AdminAvailabilityView(generics.RetrieveUpdateAPIView):
    permission_classes = [IsAuthenticated, IsAdminUser]
    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'

class ScheduleAppointmentView(generics.GenericAPIView):
    permission_classes = [IsAuthenticated, IsAdminUser]
    serializer_class = AppointmentScheduleSerializer
    queryset = AppointmentRequest.objects.all()
    lookup_field = 'pk'
    
    def post(self, request, pk):
        appointment = self.get_object()
        
        if appointment.status != 'pending_review':
            return Response(
                {'error': 'Only pending review appointments can be scheduled.'},
                status=status.HTTP_400_BAD_REQUEST
            )
        
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        
        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
        })


class RejectAppointmentView(generics.GenericAPIView):
    permission_classes = [IsAuthenticated]
    serializer_class = AppointmentRejectSerializer
    queryset = AppointmentRequest.objects.all()
    lookup_field = 'pk'
    
    def post(self, request, pk):
        appointment = self.get_object()
        
        if appointment.status != 'pending_review':
            return Response(
                {'error': 'Only pending appointments can be rejected'}, 
                status=status.HTTP_400_BAD_REQUEST
            )
        
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        
        appointment.reject_appointment(
            serializer.validated_data.get('rejection_reason', '')
        )
        EmailService.send_appointment_rejected(appointment)
        
        response_serializer = AppointmentRequestSerializer(appointment)
        return Response(response_serializer.data)
    

class AvailableDatesView(generics.GenericAPIView):
    permission_classes = [AllowAny]
    
    def get(self, 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)

class UserAppointmentsView(generics.ListAPIView):
    permission_classes = [IsAuthenticated]
    serializer_class = AppointmentRequestSerializer
    
    def get_queryset(self):
        return AppointmentRequest.objects.filter(
            email=self.request.user.email
        ).order_by('-created_at')
    

class AppointmentStatsView(generics.GenericAPIView):
    permission_classes = [IsAuthenticated, IsAdminUser]
    
    def get(self, request):
        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
        })
    
class UserAppointmentStatsView(generics.GenericAPIView):
    permission_classes = [IsAuthenticated]
    
    def post(self, request):
        email = request.data.get('email')
        stats = AppointmentRequest.objects.filter(
            email=email
        ).aggregate(
            total=Count('id'),
            pending=Count('id', filter=Q(status='pending_review')),
            scheduled=Count('id', filter=Q(status='scheduled')),
            rejected=Count('id', filter=Q(status='rejected')),
            completed=Count('id', filter=Q(status='completed'))
        )
        
        total = stats['total']
        scheduled = stats['scheduled']
        completion_rate = round((scheduled / total * 100), 2) if total > 0 else 0
        
        return Response({
            'total_requests': total,
            'pending_review': stats['pending'],
            'scheduled': scheduled,
            'rejected': stats['rejected'],
            'completed': stats['completed'],
            'completion_rate': completion_rate
        })