import { useState, type FormEvent } from "react";
import { useMutation, useQueryClient } from "@tanstack/react-query";
import { Button } from "@launchpad/ui";
import { useDevices, type DeviceWithServices } from "../../hooks/useDevices.js";
import { AdminPageHeader } from "./AdminPageHeader.js";

async function createDevice(input: { hostname: string; ip: string }) {
  const res = await fetch("/api/devices", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(input),
  });
  if (!res.ok) {
    const body = await res.json().catch(() => ({}));
    throw new Error(body.error ?? `Gerät konnte nicht angelegt werden (HTTP ${res.status})`);
  }
  return res.json();
}

async function deleteDevice(id: string) {
  const res = await fetch(`/api/devices/${id}`, { method: "DELETE" });
  if (!res.ok && res.status !== 404) {
    throw new Error(`Gerät konnte nicht gelöscht werden (HTTP ${res.status})`);
  }
}

interface ScanResult {
  scannedPorts: number;
  created: number;
  updated: number;
}

async function scanDevice(id: string): Promise<ScanResult> {
  const res = await fetch(`/api/scan/devices/${id}`, { method: "POST" });
  const body = await res.json();
  if (!res.ok) {
    throw new Error(body.detail ?? body.error ?? `Scan fehlgeschlagen (HTTP ${res.status})`);
  }
  return body;
}

function DeviceRow({ device }: { device: DeviceWithServices }) {
  const queryClient = useQueryClient();
  const [scanMessage, setScanMessage] = useState<string | null>(null);

  const scanMutation = useMutation({
    mutationFn: () => scanDevice(device.id),
    onSuccess: (result) => {
      setScanMessage(
        `${result.scannedPorts} Port(s) offen · ${result.created} neu · ${result.updated} aktualisiert`
      );
      queryClient.invalidateQueries({ queryKey: ["devices"] });
      queryClient.invalidateQueries({ queryKey: ["services"] });
    },
    onError: (err: Error) => setScanMessage(err.message),
  });

  const deleteMutation = useMutation({
    mutationFn: () => deleteDevice(device.id),
    onSuccess: () => queryClient.invalidateQueries({ queryKey: ["devices"] }),
  });

  return (
    <tr className="border-b border-black/5 last:border-0 dark:border-white/5">
      <td className="px-4 py-3">
        <div className="font-medium text-black dark:text-white">{device.hostname}</div>
        <div className="text-xs text-black/40 dark:text-white/40">{device.ip}</div>
      </td>
      <td className="px-4 py-3">
        <span
          className={`inline-flex items-center gap-1.5 text-xs ${
            device.online ? "text-emerald-600 dark:text-emerald-400" : "text-black/40 dark:text-white/40"
          }`}
        >
          <span
            className={`h-1.5 w-1.5 rounded-full ${device.online ? "bg-emerald-500" : "bg-black/20 dark:bg-white/20"}`}
          />
          {device.online ? "Online" : "Offline"}
        </span>
      </td>
      <td className="px-4 py-3 text-black/60 dark:text-white/60">{device.services.length}</td>
      <td className="px-4 py-3 text-xs text-black/40 dark:text-white/40">
        {device.lastScan ? new Date(device.lastScan).toLocaleString("de-DE") : "nie gescannt"}
      </td>
      <td className="px-4 py-3">
        <div className="flex items-center justify-end gap-2">
          {scanMessage ? (
            <span className="max-w-[16rem] truncate text-xs text-black/40 dark:text-white/40" title={scanMessage}>
              {scanMessage}
            </span>
          ) : null}
          <Button
            size="sm"
            onClick={() => {
              setScanMessage(null);
              scanMutation.mutate();
            }}
            disabled={scanMutation.isPending}
          >
            {scanMutation.isPending ? "Scanne …" : "Jetzt scannen"}
          </Button>
          <Button
            size="sm"
            variant="danger"
            onClick={() => deleteMutation.mutate()}
            disabled={deleteMutation.isPending}
          >
            Löschen
          </Button>
        </div>
      </td>
    </tr>
  );
}

function AddDeviceForm() {
  const queryClient = useQueryClient();
  const [hostname, setHostname] = useState("");
  const [ip, setIp] = useState("");

  const mutation = useMutation({
    mutationFn: createDevice,
    onSuccess: () => {
      setHostname("");
      setIp("");
      queryClient.invalidateQueries({ queryKey: ["devices"] });
    },
  });

  function handleSubmit(e: FormEvent) {
    e.preventDefault();
    if (!hostname.trim() || !ip.trim()) return;
    mutation.mutate({ hostname: hostname.trim(), ip: ip.trim() });
  }

  return (
    <form onSubmit={handleSubmit} className="flex items-end gap-2">
      <div>
        <label className="mb-1 block text-xs font-medium text-black/50 dark:text-white/50">
          Hostname
        </label>
        <input
          value={hostname}
          onChange={(e) => setHostname(e.target.value)}
          placeholder="z. B. synology"
          className="rounded-lg border border-black/10 bg-white px-3 py-1.5 text-sm
            text-black outline-none focus:border-black/30 dark:border-white/10
            dark:bg-white/5 dark:text-white dark:focus:border-white/30"
        />
      </div>
      <div>
        <label className="mb-1 block text-xs font-medium text-black/50 dark:text-white/50">
          IP-Adresse
        </label>
        <input
          value={ip}
          onChange={(e) => setIp(e.target.value)}
          placeholder="192.168.1.10"
          className="rounded-lg border border-black/10 bg-white px-3 py-1.5 text-sm
            text-black outline-none focus:border-black/30 dark:border-white/10
            dark:bg-white/5 dark:text-white dark:focus:border-white/30"
        />
      </div>
      <Button type="submit" variant="primary" disabled={mutation.isPending}>
        Gerät hinzufügen
      </Button>
      {mutation.isError ? (
        <span className="text-xs text-red-500">{(mutation.error as Error).message}</span>
      ) : null}
    </form>
  );
}

export function DevicesPage() {
  const { data: devices, isLoading, isError } = useDevices();

  return (
    <div>
      <AdminPageHeader
        title="Geräte"
        description="Alle bekannten Geräte in deinem Netzwerk. Scans laufen nur auf Knopfdruck."
      />

      <div className="mb-6">
        <AddDeviceForm />
      </div>

      {isLoading ? (
        <p className="text-sm text-black/40 dark:text-white/40">Lade Geräte …</p>
      ) : isError ? (
        <p className="text-sm text-red-500">Geräte konnten nicht geladen werden.</p>
      ) : devices && devices.length > 0 ? (
        <div className="overflow-hidden rounded-2xl border border-black/10 dark:border-white/10">
          <table className="w-full text-sm">
            <thead>
              <tr className="border-b border-black/10 bg-black/[0.02] text-left text-xs
                uppercase tracking-wide text-black/40 dark:border-white/10 dark:bg-white/5 dark:text-white/40">
                <th className="px-4 py-2 font-medium">Gerät</th>
                <th className="px-4 py-2 font-medium">Status</th>
                <th className="px-4 py-2 font-medium">Dienste</th>
                <th className="px-4 py-2 font-medium">Letzter Scan</th>
                <th className="px-4 py-2" />
              </tr>
            </thead>
            <tbody>
              {devices.map((device) => (
                <DeviceRow key={device.id} device={device} />
              ))}
            </tbody>
          </table>
        </div>
      ) : (
        <p className="text-sm text-black/40 dark:text-white/40">
          Noch keine Geräte angelegt. Füge oben ein Gerät hinzu oder nutze den FritzBox-Scan
          unter „Scanner“.
        </p>
      )}
    </div>
  );
}