from rest_framework import viewsets, permissions, status
from rest_framework.decorators import action
from rest_framework.response import Response
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import filters
from django.db.models import Count, Avg
from django.utils import timezone
from datetime import timedelta
from ..models import (
    QualityIndicator, QualityMeasurement, IncidentReport, 
    RiskAssessment, AuditPlan, AuditFinding, ImprovementProject
)
from .serializers import (
    QualityIndicatorSerializer, QualityMeasurementSerializer, IncidentReportSerializer,
    RiskAssessmentSerializer, AuditPlanSerializer, AuditFindingSerializer, 
    ImprovementProjectSerializer
)


class QualityIndicatorViewSet(viewsets.ModelViewSet):
    """ViewSet for quality indicators"""
    queryset = QualityIndicator.objects.all()
    serializer_class = QualityIndicatorSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['category', 'type', 'frequency', 'is_active', 'regulatory_requirement']
    search_fields = ['name', 'description', 'data_source']
    ordering_fields = ['name', 'category', 'created_at']
    ordering = ['name']
    
    def get_queryset(self):
        return QualityIndicator.objects.filter(tenant=self.request.user.tenant)
    
    def perform_create(self, serializer):
        serializer.save(tenant=self.request.user.tenant)


class QualityMeasurementViewSet(viewsets.ModelViewSet):
    """ViewSet for quality measurements"""
    queryset = QualityMeasurement.objects.all()
    serializer_class = QualityMeasurementSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['indicator', 'status', 'verified_by']
    search_fields = ['notes', 'data_source_reference']
    ordering_fields = ['measurement_date', 'value', 'created_at']
    ordering = ['-measurement_date']
    
    def get_queryset(self):
        return QualityMeasurement.objects.filter(tenant=self.request.user.tenant)


class IncidentReportViewSet(viewsets.ModelViewSet):
    """ViewSet for incident reports"""
    queryset = IncidentReport.objects.all()
    serializer_class = IncidentReportSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['incident_type', 'severity', 'category', 'status', 'priority']
    search_fields = ['incident_number', 'title', 'description', 'location']
    ordering_fields = ['incident_date', 'severity', 'created_at']
    ordering = ['-incident_date']
    
    def get_queryset(self):
        return IncidentReport.objects.filter(tenant=self.request.user.tenant)


class RiskAssessmentViewSet(viewsets.ModelViewSet):
    """ViewSet for risk assessments"""
    queryset = RiskAssessment.objects.all()
    serializer_class = RiskAssessmentSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['risk_category', 'risk_type', 'risk_level', 'status']
    search_fields = ['title', 'description', 'current_controls']
    ordering_fields = ['risk_score', 'review_date', 'created_at']
    ordering = ['-risk_score']
    
    def get_queryset(self):
        return RiskAssessment.objects.filter(tenant=self.request.user.tenant)


class AuditPlanViewSet(viewsets.ModelViewSet):
    """ViewSet for audit plans"""
    queryset = AuditPlan.objects.all()
    serializer_class = AuditPlanSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['audit_type', 'status', 'priority', 'regulatory_requirement']
    search_fields = ['title', 'description', 'scope']
    ordering_fields = ['planned_start_date', 'created_at']
    ordering = ['planned_start_date']
    
    def get_queryset(self):
        return AuditPlan.objects.filter(tenant=self.request.user.tenant)


class AuditFindingViewSet(viewsets.ModelViewSet):
    """ViewSet for audit findings"""
    queryset = AuditFinding.objects.all()
    serializer_class = AuditFindingSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['audit_plan', 'finding_type', 'severity', 'category', 'status']
    search_fields = ['finding_number', 'title', 'description', 'evidence']
    ordering_fields = ['severity', 'target_completion_date', 'created_at']
    ordering = ['-severity', 'target_completion_date']
    
    def get_queryset(self):
        return AuditFinding.objects.filter(tenant=self.request.user.tenant)


class ImprovementProjectViewSet(viewsets.ModelViewSet):
    """ViewSet for improvement projects"""
    queryset = ImprovementProject.objects.all()
    serializer_class = ImprovementProjectSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['project_type', 'methodology', 'status', 'phase']
    search_fields = ['project_number', 'title', 'description', 'problem_statement']
    ordering_fields = ['planned_start_date', 'created_at']
    ordering = ['planned_start_date']
    
    def get_queryset(self):
        return ImprovementProject.objects.filter(tenant=self.request.user.tenant)