"use client";

import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { useParams, useRouter } from "next/navigation";
import { api } from "@/lib/api";
import type { DocumentTemplate } from "@/lib/types";
import { TEMPLATE_CATEGORY_LABELS } from "@/lib/types";
import { Breadcrumb } from "@/components/layout/Breadcrumb";
import { TemplateEditor } from "@/components/templates/TemplateEditor";
import Link from "next/link";
import {
  Loader2,
  Lock,
  Trash2,
  FileDown,
  ArrowRight,
} from "lucide-react";
import { toast } from "sonner";
import { useState } from "react";

export default function TemplateDetailPage() {
  const { id } = useParams<{ id: string }>();
  const router = useRouter();
  const queryClient = useQueryClient();
  const [isEditing, setIsEditing] = useState(false);

  const { data: template, isLoading } = useQuery({
    queryKey: ["template", id],
    queryFn: () => api.get<DocumentTemplate>(`/templates/${id}`),
  });

  const deleteMutation = useMutation({
    mutationFn: () => api.delete(`/templates/${id}`),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["templates"] });
      toast.success("Vorlage gelöscht");
      router.push("/vorlagen");
    },
    onError: () => toast.error("Fehler beim Löschen"),
  });

  const updateMutation = useMutation({
    mutationFn: (data: Partial<DocumentTemplate>) =>
      api.put<DocumentTemplate>(`/templates/${id}`, data),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["template", id] });
      queryClient.invalidateQueries({ queryKey: ["templates"] });
      toast.success("Vorlage gespeichert");
      setIsEditing(false);
    },
    onError: () => toast.error("Fehler beim Speichern"),
  });

  if (isLoading) {
    return (
      <div className="flex items-center justify-center py-12">
        <Loader2 className="h-5 w-5 animate-spin text-neutral-400" />
      </div>
    );
  }

  if (!template) {
    return (
      <div className="py-12 text-center text-sm text-neutral-500">
        Vorlage nicht gefunden
      </div>
    );
  }

  return (
    <div className="animate-fade-in space-y-4">
      <Breadcrumb
        items={[
          { label: "Dashboard", href: "/dashboard" },
          { label: "Vorlagen", href: "/vorlagen" },
          { label: template.name },
        ]}
      />

      <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
        <div>
          <div className="flex items-center gap-2">
            <h1 className="text-lg font-semibold text-neutral-900">
              {template.name}
            </h1>
            {template.is_system && (
              <Lock className="h-4 w-4 text-neutral-400" aria-label="Systemvorlage" />
            )}
          </div>
          <div className="mt-1 flex items-center gap-2">
            <span className="rounded-full bg-neutral-100 px-2 py-0.5 text-xs text-neutral-600">
              {TEMPLATE_CATEGORY_LABELS[template.category] ?? template.category}
            </span>
            {template.description && (
              <span className="text-xs text-neutral-500">
                {template.description}
              </span>
            )}
          </div>
        </div>

        <div className="flex items-center gap-2">
          <Link
            href={`/vorlagen/${id}/render`}
            className="flex items-center gap-1.5 rounded-md bg-neutral-900 px-3 py-1.5 text-sm font-medium text-white transition-colors hover:bg-neutral-800"
          >
            <FileDown className="h-3.5 w-3.5" />
            Dokument erstellen
            <ArrowRight className="h-3.5 w-3.5" />
          </Link>
          {!template.is_system && (
            <>
              <button
                onClick={() => setIsEditing(!isEditing)}
                className="rounded-md border border-neutral-200 bg-white px-3 py-1.5 text-sm text-neutral-700 transition-colors hover:bg-neutral-50"
              >
                {isEditing ? "Abbrechen" : "Bearbeiten"}
              </button>
              <button
                onClick={() => {
                  if (confirm("Vorlage wirklich löschen?")) {
                    deleteMutation.mutate();
                  }
                }}
                className="rounded-md border border-red-200 bg-white p-1.5 text-red-600 transition-colors hover:bg-red-50"
              >
                <Trash2 className="h-4 w-4" />
              </button>
            </>
          )}
        </div>
      </div>

      {isEditing ? (
        <TemplateEditor
          template={template}
          onSave={(data) => updateMutation.mutate(data)}
          isSaving={updateMutation.isPending}
        />
      ) : (
        <div className="space-y-4">
          {/* Variables */}
          {template.variables && template.variables.length > 0 && (
            <div className="rounded-lg border border-neutral-200 bg-white p-4">
              <h3 className="mb-2 text-sm font-medium text-neutral-700">
                Variablen
              </h3>
              <div className="flex flex-wrap gap-1.5">
                {template.variables.map((v: string) => (
                  <code
                    key={v}
                    className="rounded bg-neutral-100 px-1.5 py-0.5 text-xs text-neutral-600"
                  >
                    {`{{${v}}}`}
                  </code>
                ))}
              </div>
            </div>
          )}

          {/* Content preview */}
          <div className="rounded-lg border border-neutral-200 bg-white p-6">
            <h3 className="mb-3 text-sm font-medium text-neutral-700">
              Vorschau
            </h3>
            <div className="prose prose-sm prose-neutral max-w-none whitespace-pre-wrap font-mono text-xs leading-relaxed text-neutral-700">
              {template.content}
            </div>
          </div>
        </div>
      )}
    </div>
  );
}