from rest_framework import viewsets, permissions, status
from rest_framework.decorators import action
from rest_framework.response import Response

from .models import (
    ProductSpecification, Facility, OriginZone, CollectorGroup, HarvestIntake,
    IntakeBatchLineage, DueDiligenceCase, EUDREvidence, RiskAssessment,
    MitigationAction, DueDiligenceStatementReference,
)
from .serializers import (
    ProductSpecificationSerializer, FacilitySerializer, OriginZoneSerializer,
    CollectorGroupSerializer, HarvestIntakeSerializer, IntakeBatchLineageSerializer,
    DueDiligenceCaseSerializer, EUDREvidenceSerializer, RiskAssessmentSerializer,
    MitigationActionSerializer, DueDiligenceStatementReferenceSerializer,
)
from .permissions import IsOpsOrAdmin, IsAdmin
from . import services


class ProductSpecificationViewSet(viewsets.ModelViewSet):
    queryset = ProductSpecification.objects.prefetch_related("parameters").all()
    serializer_class = ProductSpecificationSerializer
    permission_classes = [IsOpsOrAdmin]

    def get_permissions(self):
        if self.action in ("create", "update", "partial_update", "destroy"):
            return [permission() for permission in [IsAdmin]]
        return [permission() for permission in [IsOpsOrAdmin]]


class FacilityViewSet(viewsets.ModelViewSet):
    queryset = Facility.objects.all()
    serializer_class = FacilitySerializer
    permission_classes = [IsOpsOrAdmin]


class OriginZoneViewSet(viewsets.ModelViewSet):
    queryset = OriginZone.objects.select_related("facility", "verified_by").all()
    serializer_class = OriginZoneSerializer
    permission_classes = [IsOpsOrAdmin]

    @action(detail=True, methods=["post"])
    def verify(self, request, pk=None):
        zone = self.get_object()
        outcome = request.data.get("verified", "true")
        verified = str(outcome).lower() in ("true", "1", "yes")
        zone.verification_status = "verified" if verified else "rejected"
        zone.verified_by = request.user
        from django.utils import timezone
        zone.verified_at = timezone.now()
        zone.save()
        return Response(OriginZoneSerializer(zone).data)


class CollectorGroupViewSet(viewsets.ModelViewSet):
    queryset = CollectorGroup.objects.all()
    serializer_class = CollectorGroupSerializer
    permission_classes = [IsOpsOrAdmin]


class HarvestIntakeViewSet(viewsets.ModelViewSet):
    queryset = HarvestIntake.objects.select_related("origin_zone", "collector_group").all()
    serializer_class = HarvestIntakeSerializer
    permission_classes = [IsOpsOrAdmin]


class IntakeBatchLineageViewSet(viewsets.ModelViewSet):
    queryset = IntakeBatchLineage.objects.select_related("batch", "harvest_intake").all()
    serializer_class = IntakeBatchLineageSerializer
    permission_classes = [IsOpsOrAdmin]

    def perform_create(self, serializer):
        lineage = serializer.save()
        services.ensure_due_diligence_case(lineage.batch)


class EUDREvidenceViewSet(viewsets.ModelViewSet):
    queryset = EUDREvidence.objects.select_related("case", "verified_by").all()
    serializer_class = EUDREvidenceSerializer
    permission_classes = [IsOpsOrAdmin]

    def perform_create(self, serializer):
        evidence = serializer.save()
        case = evidence.case
        services.run_completeness_check(case)


class RiskAssessmentViewSet(viewsets.ModelViewSet):
    queryset = RiskAssessment.objects.select_related("case", "assessed_by").all()
    serializer_class = RiskAssessmentSerializer
    permission_classes = [IsOpsOrAdmin]


class MitigationActionViewSet(viewsets.ModelViewSet):
    queryset = MitigationAction.objects.select_related("case").all()
    serializer_class = MitigationActionSerializer
    permission_classes = [IsOpsOrAdmin]

    @action(detail=True, methods=["post"])
    def complete(self, request, pk=None):
        mitigation = self.get_object()
        mitigation.status = MitigationAction.Status.VERIFIED
        from django.utils import timezone
        mitigation.completed_at = timezone.now()
        mitigation.save()
        services.run_completeness_check(mitigation.case)
        return Response(MitigationActionSerializer(mitigation).data)


class DueDiligenceStatementReferenceViewSet(viewsets.ModelViewSet):
    queryset = DueDiligenceStatementReference.objects.select_related("case", "submitted_by").all()
    serializer_class = DueDiligenceStatementReferenceSerializer
    permission_classes = [IsOpsOrAdmin]


class DueDiligenceCaseViewSet(viewsets.ModelViewSet):
    queryset = DueDiligenceCase.objects.select_related(
        "batch", "approved_by", "assessed_by"
    ).prefetch_related("evidence", "risk_assessments", "mitigation_actions", "statement_references").order_by("-updated_at").all()
    serializer_class = DueDiligenceCaseSerializer
    permission_classes = [IsOpsOrAdmin]

    def perform_create(self, serializer):
        serializer.save()

    @action(detail=True, methods=["post"])
    def check(self, request, pk=None):
        case = self.get_object()
        services.run_completeness_check(case)
        return Response(DueDiligenceCaseSerializer(case).data)

    @action(detail=True, methods=["post"])
    def assess_risk(self, request, pk=None):
        case = self.get_object()
        risk = services.evaluate_risk(case, user=request.user)
        return Response({"risk_assessment_id": str(risk.id), **RiskAssessmentSerializer(risk).data})

    @action(detail=True, methods=["post"])
    def approve(self, request, pk=None):
        case = self.get_object()
        try:
            services.approve_case(case, request.user)
        except ValueError as exc:
            return Response({"detail": str(exc)}, status=status.HTTP_400_BAD_REQUEST)
        return Response(DueDiligenceCaseSerializer(case).data)

    @action(detail=True, methods=["post"])
    def reject(self, request, pk=None):
        case = self.get_object()
        reason = request.data.get("reason", "")
        try:
            services.reject_case(case, request.user, reason)
        except ValueError as exc:
            return Response({"detail": str(exc)}, status=status.HTTP_400_BAD_REQUEST)
        return Response(DueDiligenceCaseSerializer(case).data)

    @action(detail=True, methods=["post"])
    def record_submission(self, request, pk=None):
        case = self.get_object()
        dds_reference = request.data.get("dds_reference", "")
        submission_date = request.data.get("submission_date")
        if not dds_reference:
            return Response({"detail": "dds_reference is required"}, status=status.HTTP_400_BAD_REQUEST)
        ref = services.record_submission(case, request.user, dds_reference, submission_date)
        return Response(DueDiligenceStatementReferenceSerializer(ref).data)

    @action(detail=True, methods=["get"])
    def evidence_package(self, request, pk=None):
        case = self.get_object()
        return Response(services.evidence_package(case))