import csv

from django import forms
from django.contrib import messages
from django.core.validators import FileExtensionValidator, ValidationError
from django.db import models
from django.shortcuts import get_object_or_404, redirect
from django.utils.decorators import method_decorator
from django.views.generic import FormView, ListView

from users.decorators import admin_required
from users.models import Domain
from users.services import DomainService
from users.views.admin.domains import DomainValidator


@method_decorator(admin_required, name="dispatch")
class FederationRoot(ListView):
    template_name = "admin/federation.html"
    paginate_by = 50

    def get(self, request, *args, **kwargs):
        self.query = request.GET.get("query")
        self.extra_context = {
            "section": "federation",
            "query": self.query or "",
        }
        return super().get(request, *args, **kwargs)

    def get_queryset(self):
        domains = (
            Domain.objects.filter(local=False)
            .annotate(num_users=models.Count("identities"))
            .order_by("domain")
        )
        if self.query:
            domains = domains.filter(domain__icontains=self.query)
        return domains


@method_decorator(admin_required, name="dispatch")
class FederationEdit(FormView):
    template_name = "admin/federation_edit.html"
    extra_context = {"section": "federation"}

    class form_class(forms.Form):
        blocked = forms.BooleanField(
            help_text="If this domain is blocked from interacting with this server.\nAll incoming posts from this domain will be irrecoverably dropped.",
            widget=forms.Select(choices=[(True, "Blocked"), (False, "Not Blocked")]),
            required=False,
        )
        notes = forms.CharField(
            label="Notes",
            widget=forms.Textarea(
                attrs={
                    "rows": 3,
                },
            ),
            required=False,
        )

    def dispatch(self, request, domain):
        self.domain = get_object_or_404(
            Domain.objects.filter(local=False), domain=domain
        )
        return super().dispatch(request)

    def get_context_data(self, *args, **kwargs):
        context = super().get_context_data(*args, **kwargs)
        context["domain"] = self.domain
        context["page"] = self.request.GET.get("page")
        return context

    def form_valid(self, form):
        self.domain.blocked = form.cleaned_data["blocked"]
        self.domain.notes = form.cleaned_data["notes"] or None
        self.domain.save()
        return redirect(Domain.urls.root_federation)

    def get_initial(self):
        return {
            "blocked": self.domain.blocked,
            "notes": self.domain.notes,
        }


@method_decorator(admin_required, name="dispatch")
class FederationBlocklist(FormView):
    template_name = "admin/federation_blocklist.html"
    extra_context = {"section": "federation"}
    error_msg = "The uploaded file has an invalid blocklist CSV format."
    success_msg = "The blocklist CSV was processed processed with success!"

    class form_class(forms.Form):
        blocklist = forms.FileField(
            help_text=(
                "Blocklist file with one domain per line. "
                "CSVs with 'domain' and '#domain' headers are also supported."
            ),
            validators=[FileExtensionValidator(allowed_extensions=["txt", "csv"])],
        )

    def form_valid(self, form):
        validator = DomainValidator()
        domains = []

        try:
            lines = form.cleaned_data["blocklist"].read().decode("utf-8").splitlines()

            if "#domain" in lines[0] or "domain" in lines[0]:
                reader = csv.DictReader(lines)
            else:
                reader = csv.DictReader(lines, fieldnames=["#domain"])

            for row in reader:
                domain = row.get("#domain", row.get("domain", "")).strip()

                try:
                    validator(domain)
                except ValidationError:
                    # skip adding invalid domain
                    # to the blocklist
                    continue

                domains.append(domain)
        except (TypeError, ValueError):
            messages.error(self.request, self.error_msg)
            return redirect(".")

        if not domains:
            messages.error(self.request, self.error_msg)
            return redirect(".")

        DomainService.block(domains)

        messages.success(self.request, self.success_msg)
        return redirect("admin_federation")

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["page"] = self.request.GET.get("page")
        return context