from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from django.db.models import Count, Q
from django.shortcuts import redirect
from django.utils import timezone
from django.views.generic import TemplateView, ListView, DetailView
from django.shortcuts import get_object_or_404

from apps.batches.models import ProcessingBatch
from apps.qc.models import QCResult
from apps.shipments.models import Shipment
from apps.capa.models import CAPARecord
from apps.documents.models import Document, CertificateOfAnalysis
from apps.esg.models import ESGFieldReport
from apps.notifications.models import Notification
from apps.compliance.models import DueDiligenceCase


class OpsRequiredMixin(UserPassesTestMixin):
    def test_func(self):
        user = self.request.user
        return user.is_authenticated and (user.role in ('ops', 'admin') or user.is_superuser)


class DashboardView(OpsRequiredMixin, TemplateView):
    template_name = 'ops/dashboard.html'

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['total_batches'] = ProcessingBatch.objects.count()
        ctx['batches_by_status'] = {
            s: ProcessingBatch.objects.filter(status=s).count()
            for s, _ in ProcessingBatch.Status.choices
        }
        ctx['recent_qc'] = QCResult.objects.select_related('batch').order_by('-tested_at')[:10]
        ctx['qc_summary'] = QCResult.objects.aggregate(
            passed=Count('id', filter=Q(overall_pass=True)),
            failed=Count('id', filter=Q(overall_pass=False)),
        )
        ctx['active_shipments'] = Shipment.objects.exclude(status='delivered').count()
        ctx['open_capas'] = CAPARecord.objects.filter(status__in=('open', 'in_progress')).count()
        ctx['recent_notifications'] = Notification.objects.filter(
            user=self.request.user, is_read=False
        )[:5]
        ctx['recent_batches'] = ProcessingBatch.objects.order_by('-created_at')[:5]
        return ctx


class BatchListView(OpsRequiredMixin, ListView):
    model = ProcessingBatch
    template_name = 'ops/batch_list.html'
    context_object_name = 'batches'
    paginate_by = 25

    def get_queryset(self):
        qs = ProcessingBatch.objects.all()
        status = self.request.GET.get('status')
        grade = self.request.GET.get('grade')
        search = self.request.GET.get('q')
        if status:
            qs = qs.filter(status=status)
        if grade:
            qs = qs.filter(grade=grade)
        if search:
            qs = qs.filter(batch_reference__icontains=search)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['status_choices'] = ProcessingBatch.Status.choices
        ctx['grade_choices'] = ProcessingBatch.Grade.choices
        ctx['current_status'] = self.request.GET.get('status', '')
        ctx['current_grade'] = self.request.GET.get('grade', '')
        ctx['current_q'] = self.request.GET.get('q', '')
        return ctx


class BatchDetailView(OpsRequiredMixin, DetailView):
    model = ProcessingBatch
    template_name = 'ops/batch_detail.html'
    context_object_name = 'batch'

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        batch = self.object
        ctx['qc_results'] = QCResult.objects.filter(batch=batch)
        ctx['shipments'] = Shipment.objects.filter(batch=batch)
        ctx['capa_records'] = CAPARecord.objects.filter(batch=batch)
        ctx['documents'] = Document.objects.filter(batch=batch)
        ctx['esg_reports'] = ESGFieldReport.objects.filter(batch=batch)
        return ctx


class QCListView(OpsRequiredMixin, ListView):
    model = QCResult
    template_name = 'ops/qc_list.html'
    context_object_name = 'results'
    paginate_by = 25

    def get_queryset(self):
        qs = QCResult.objects.select_related('batch').all()
        passed = self.request.GET.get('passed')
        if passed == '1':
            qs = qs.filter(overall_pass=True)
        elif passed == '0':
            qs = qs.filter(overall_pass=False)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['current_passed'] = self.request.GET.get('passed', '')
        return ctx


class QCDetailView(OpsRequiredMixin, DetailView):
    model = QCResult
    template_name = 'ops/qc_detail.html'
    context_object_name = 'result'


class ShipmentListView(OpsRequiredMixin, ListView):
    model = Shipment
    template_name = 'ops/shipment_list.html'
    context_object_name = 'shipments'
    paginate_by = 25

    def get_queryset(self):
        qs = Shipment.objects.select_related('batch').all()
        status = self.request.GET.get('status')
        if status:
            qs = qs.filter(status=status)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['status_choices'] = Shipment.Status.choices
        ctx['current_status'] = self.request.GET.get('status', '')
        return ctx


class ShipmentDetailView(OpsRequiredMixin, DetailView):
    model = Shipment
    template_name = 'ops/shipment_detail.html'
    context_object_name = 'shipment'


class CAPAListView(OpsRequiredMixin, ListView):
    model = CAPARecord
    template_name = 'ops/capa_list.html'
    context_object_name = 'records'
    paginate_by = 25

    def get_queryset(self):
        qs = CAPARecord.objects.select_related('batch').all()
        status = self.request.GET.get('status')
        if status:
            qs = qs.filter(status=status)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['status_choices'] = CAPARecord.Status.choices
        ctx['current_status'] = self.request.GET.get('status', '')
        return ctx


class CAPADetailView(OpsRequiredMixin, DetailView):
    model = CAPARecord
    template_name = 'ops/capa_detail.html'
    context_object_name = 'record'


class DocumentListView(OpsRequiredMixin, ListView):
    model = Document
    template_name = 'ops/document_list.html'
    context_object_name = 'documents'
    paginate_by = 25

    def get_queryset(self):
        qs = Document.objects.select_related('batch', 'uploaded_by').all()
        doc_type = self.request.GET.get('doc_type')
        if doc_type:
            qs = qs.filter(doc_type=doc_type)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['doc_type_choices'] = Document.DocType.choices
        ctx['current_doc_type'] = self.request.GET.get('doc_type', '')
        return ctx


class ESGListView(OpsRequiredMixin, ListView):
    model = ESGFieldReport
    template_name = 'ops/esg_list.html'
    context_object_name = 'reports'
    paginate_by = 25

    def get_queryset(self):
        return ESGFieldReport.objects.select_related('batch').all()


class QCVerifyListView(OpsRequiredMixin, ListView):
    model = QCResult
    template_name = 'ops/qc_verify_list.html'
    context_object_name = 'results'
    paginate_by = 25

    def get_queryset(self):
        qs = QCResult.objects.select_related('batch', 'entered_by').filter(
            verification_status=QCResult.VerificationStatus.DRAFT
        )
        passed = self.request.GET.get('passed')
        if passed == '1':
            qs = qs.filter(overall_pass=True)
        elif passed == '0':
            qs = qs.filter(overall_pass=False)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['current_passed'] = self.request.GET.get('passed', '')
        return ctx


class QCVerifyDetailView(OpsRequiredMixin, DetailView):
    model = QCResult
    template_name = 'ops/qc_verify_detail.html'
    context_object_name = 'result'

    def post(self, request, *args, **kwargs):
        from django.contrib import messages
        from apps.compliance.services import create_coa_for_qc

        qc = self.get_object()
        user = request.user
        if qc.entered_by is not None and qc.entered_by_id == user.id:
            messages.error(request, 'The submitter cannot approve their own QC result (four-eyes control).')
            return redirect(self.request.path)

        approved = request.POST.get('approved') == '1'
        if approved:
            if not qc.overall_pass:
                messages.error(request, 'A failed QC result cannot be approved; it remains quarantined with an open CAPA.')
                return redirect(self.request.path)
            qc.verification_status = QCResult.VerificationStatus.APPROVED
            qc.verified_by = user
            qc.approved_at = timezone.now()
            qc.save()
            coa = create_coa_for_qc(qc, approved_by=user)
            messages.success(request, f'QC result approved. CoA created (status: {coa.status}).')
            return redirect('ops:coa_review_detail', pk=coa.pk)
        else:
            qc.verification_status = QCResult.VerificationStatus.REJECTED
            qc.verified_by = user
            qc.approved_at = timezone.now()
            qc.save()
            messages.warning(request, 'QC result rejected.')
            return redirect('ops:qc_verify_list')


class COAReviewListView(OpsRequiredMixin, ListView):
    model = CertificateOfAnalysis
    template_name = 'ops/coa_review_list.html'
    context_object_name = 'coas'
    paginate_by = 25

    def get_queryset(self):
        qs = CertificateOfAnalysis.objects.select_related('batch', 'qc_result', 'quality_approved_by').all()
        status = self.request.GET.get('status')
        if status:
            qs = qs.filter(status=status)
        else:
            qs = qs.filter(status=CertificateOfAnalysis.Status.PENDING_APPROVAL)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['status_choices'] = CertificateOfAnalysis.Status.choices
        ctx['current_status'] = self.request.GET.get('status', '')
        return ctx


class COAReviewDetailView(OpsRequiredMixin, DetailView):
    model = CertificateOfAnalysis
    template_name = 'ops/coa_review_detail.html'
    context_object_name = 'coa'

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['lab_documents'] = Document.objects.filter(batch=self.object.batch, doc_type=Document.DocType.LAB_REPORT)
        return ctx

    def post(self, request, *args, **kwargs):
        from django.contrib import messages
        from apps.compliance.services import publish_coa

        coa = self.get_object()
        if request.POST.get('action') == 'approve':
            try:
                publish_coa(coa, released_by=request.user)
                messages.success(request, 'CoA published to buyers.')
            except ValueError as exc:
                messages.error(request, str(exc))
        return redirect(self.request.path)


class EUDRCaseListView(OpsRequiredMixin, ListView):
    model = DueDiligenceCase
    template_name = 'ops/eudr_list.html'
    context_object_name = 'cases'
    paginate_by = 25

    def get_queryset(self):
        qs = DueDiligenceCase.objects.select_related('batch', 'approved_by').all()
        status = self.request.GET.get('status')
        if status:
            qs = qs.filter(status=status)
        return qs

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['status_choices'] = DueDiligenceCase.Status.choices
        ctx['current_status'] = self.request.GET.get('status', '')
        return ctx


class EUDRCaseDetailView(OpsRequiredMixin, DetailView):
    model = DueDiligenceCase
    template_name = 'ops/eudr_detail.html'
    context_object_name = 'case'

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        case = self.object
        ctx['lineage'] = list(case.batch.intake_lineage.select_related(
            'harvest_intake', 'harvest_intake__origin_zone', 'harvest_intake__collector_group'
        ))
        ctx['evidence'] = case.evidence.all()
        ctx['risk_assessments'] = case.risk_assessments.all()
        ctx['mitigation_actions'] = case.mitigation_actions.all()
        ctx['statement_references'] = case.statement_references.all()
        return ctx

    def post(self, request, *args, **kwargs):
        from django.contrib import messages
        from apps.compliance import services

        case = self.get_object()
        action = request.POST.get('action')
        try:
            if action == 'check':
                services.run_completeness_check(case)
                messages.info(request, 'Completeness check completed.')
            elif action == 'assess_risk':
                services.evaluate_risk(case, user=request.user)
                messages.info(request, 'Risk assessment recorded.')
            elif action == 'approve':
                services.approve_case(case, request.user)
                messages.success(request, 'Case approved.')
            elif action == 'reject':
                services.reject_case(case, request.user, request.POST.get('reason', ''))
                messages.warning(request, 'Case rejected.')
            elif action == 'record_submission':
                ref = request.POST.get('dds_reference')
                if not ref:
                    messages.error(request, 'DDS reference required.')
                else:
                    services.record_submission(case, request.user, ref, request.POST.get('submission_date') or None)
                    messages.success(request, 'External submission recorded.')
        except ValueError as exc:
            messages.error(request, str(exc))
        return redirect(self.request.path)