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

from apps.batches.models import ProcessingBatch
from apps.shipments.models import Shipment
from apps.documents.downloads import file_response
from apps.documents.models import CertificateOfAnalysis, Document
from apps.esg.models import ESGFieldReport
from apps.subscriptions.models import Subscription
from apps.guides.views import GuideDetailView as BaseGuideDetailView
from apps.guides.views import GuideIndexView as BaseGuideIndexView


class BuyerRequiredMixin(UserPassesTestMixin):
    def test_func(self):
        user = self.request.user
        return user.is_authenticated and (user.role in ("buyer", "admin") or user.is_superuser)


class DashboardView(BuyerRequiredMixin, TemplateView):
    template_name = "portal/dashboard.html"

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx["total_batches"] = ProcessingBatch.objects.count()
        ctx["recent_batches"] = ProcessingBatch.objects.order_by("-created_at")[:5]
        ctx["documents"] = Document.objects.filter(visibility="buyer").order_by("-uploaded_at")[:5]
        ctx["active_shipments"] = Shipment.objects.exclude(status="delivered").count()
        ctx["subscription"] = Subscription.objects.filter(user=self.request.user).first()
        return ctx


class BatchListView(BuyerRequiredMixin, ListView):
    model = ProcessingBatch
    template_name = "portal/batch_list.html"
    context_object_name = "batches"
    paginate_by = 25

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

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


class BatchDetailView(BuyerRequiredMixin, DetailView):
    model = ProcessingBatch
    template_name = "portal/batch_detail.html"
    context_object_name = "batch"

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        b = self.object
        ctx["shipments"] = Shipment.objects.filter(batch=b)
        ctx["documents"] = Document.objects.filter(batch=b, visibility="buyer")
        ctx["esg_reports"] = ESGFieldReport.objects.filter(batch=b)
        return ctx


class DocumentListView(BuyerRequiredMixin, ListView):
    model = Document
    template_name = "portal/document_list.html"
    context_object_name = "documents"
    paginate_by = 25

    def get_queryset(self):
        qs = Document.objects.filter(visibility="buyer").select_related("batch", "uploaded_by")
        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 DocumentDownloadView(BuyerRequiredMixin, View):
    """Serve the stored file behind a buyer-visible document.

    A buyer may only fetch files from documents marked buyer-visible, so a
    guessed document id belonging to an operations-only row is a 404 rather
    than a leak.
    """

    def get(self, request, pk):
        doc = get_object_or_404(Document, pk=pk, visibility=Document.Visibility.BUYER)
        return file_response(doc.file_url, doc.file_name)


class CoADownloadView(BuyerRequiredMixin, View):
    """Serve the summary PDF of a published certificate of analysis.

    Only a published certificate is downloadable, matching the compliance page
    that links to it: a certificate still awaiting release stays internal.
    """

    def get(self, request, pk):
        coa = get_object_or_404(
            CertificateOfAnalysis,
            pk=pk,
            status=CertificateOfAnalysis.Status.PUBLISHED,
        )
        return file_response(coa.file_url, coa.file_name)


class SubscriptionView(BuyerRequiredMixin, DetailView):
    model = Subscription
    template_name = "portal/subscription.html"
    context_object_name = "sub"

    def get_object(self):
        return Subscription.objects.filter(user=self.request.user).first()


class ChatView(BuyerRequiredMixin, TemplateView):
    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        from apps.ai.models import AgentConfig
        user = self.request.user
        if user.role in ("admin", "ops") or user.is_superuser:
            ctx["agents"] = AgentConfig.objects.filter(is_active=True)
        else:
            ctx["agents"] = AgentConfig.objects.filter(is_active=True, user__isnull=True)
        return ctx
    template_name = "portal/chat.html"


class ChatEmbedView(BuyerRequiredMixin, TemplateView):
    template_name = "portal/chat_embed.html"

    def dispatch(self, request, *args, **kwargs):
        response = super().dispatch(request, *args, **kwargs)
        response["X-Frame-Options"] = "ALLOWALL"
        return response


class ComplianceView(BuyerRequiredMixin, TemplateView):
    template_name = "portal/compliance.html"

    def get_context_data(self, **kwargs):
        from apps.compliance.models import DueDiligenceCase
        from apps.documents.models import CertificateOfAnalysis

        ctx = super().get_context_data(**kwargs)
        ctx["approved_coas"] = CertificateOfAnalysis.objects.filter(
            status=CertificateOfAnalysis.Status.PUBLISHED
        ).select_related("batch", "quality_approved_by").order_by("-published_at")
        ctx["eudr_cases"] = DueDiligenceCase.objects.select_related("batch", "approved_by").order_by("-updated_at")
        return ctx


class GuideIndexView(BuyerRequiredMixin, BaseGuideIndexView):
    template_name = "guides/index_portal.html"


class GuideDetailView(BuyerRequiredMixin, BaseGuideDetailView):
    template_name = "guides/detail_portal.html"