"use client";

import {
  BeakerIcon,
  BellAlertIcon,
  CheckCircleIcon,
  ClockIcon,
  FireIcon,
} from "@heroicons/react/24/outline";
import { useEffect, useState } from "react";
import { useSession } from "@/lib/auth-client";
import {
  ReminderKind,
  ReminderRule,
  ReminderSettings,
  defaultReminderSettings,
  loadHellthData,
  saveHellthData,
} from "@/lib/hellth-data";

const reminderMeta: Record<
  ReminderKind,
  { title: string; description: string; icon: typeof BeakerIcon; color: string }
> = {
  water: {
    title: "Wasser trinken",
    description: "Regelmäßig kleine Trinkimpulse statt abends alles nachholen.",
    icon: BeakerIcon,
    color: "text-blue-500",
  },
  snack: {
    title: "Snack prüfen",
    description: "Hilft, geplante Snacks bewusst zu essen und ungeplantes Snacken zu vermeiden.",
    icon: FireIcon,
    color: "text-orange-500",
  },
  movement: {
    title: "Kurz bewegen",
    description: "Steh vom Schreibtisch auf, streck dich oder geh ein paar Schritte.",
    icon: ClockIcon,
    color: "text-emerald-500",
  },
};

function permissionLabel(permission: NotificationPermission | "unsupported") {
  if (permission === "granted") return "Benachrichtigungen sind erlaubt.";
  if (permission === "denied") return "Benachrichtigungen sind im Browser blockiert.";
  if (permission === "unsupported") return "Dieser Browser unterstützt keine Web-Benachrichtigungen.";
  return "Benachrichtigungen sind noch nicht aktiviert.";
}

export default function ErinnerungenPage() {
  const { data: session } = useSession();
  const userKey = session?.user?.id ?? session?.user?.email ?? null;
  const [settings, setSettings] = useState<ReminderSettings>(defaultReminderSettings);
  const [permission, setPermission] = useState<NotificationPermission | "unsupported">("default");
  const [saved, setSaved] = useState(false);

  useEffect(() => {
    if (!userKey) return;
    setSettings(loadHellthData(userKey).reminders);
    setPermission(typeof Notification === "undefined" ? "unsupported" : Notification.permission);
  }, [userKey]);

  function persist(nextSettings: ReminderSettings) {
    if (!userKey) return;
    setSettings(nextSettings);
    const data = loadHellthData(userKey);
    saveHellthData({ ...data, reminders: nextSettings }, userKey);
    setSaved(true);
    window.setTimeout(() => setSaved(false), 1500);
  }

  function updateRule(kind: ReminderKind, patch: Partial<ReminderRule>) {
    persist({
      ...settings,
      rules: {
        ...settings.rules,
        [kind]: { ...settings.rules[kind], ...patch },
      },
    });
  }

  async function requestPermission() {
    if (typeof Notification === "undefined") {
      setPermission("unsupported");
      return;
    }
    const result = await Notification.requestPermission();
    setPermission(result);
    persist({
      ...settings,
      enabled: result === "granted" ? settings.enabled : false,
      permissionRequestedAt: new Date().toISOString(),
    });
  }

  async function sendTest(kind: ReminderKind) {
    if (typeof Notification === "undefined" || Notification.permission !== "granted") return;
    const rule = settings.rules[kind];
    if ("serviceWorker" in navigator) {
      try {
        const registration = await navigator.serviceWorker.ready;
        await registration.showNotification(`Hellth Hub: ${reminderMeta[kind].title}`, {
          body: rule.message,
          tag: `hellth-test-${kind}`,
        });
        return;
      } catch {
        // Fall through to regular notification.
      }
    }
    new Notification(`Hellth Hub: ${reminderMeta[kind].title}`, { body: rule.message });
  }

  return (
    <div className="mx-auto max-w-5xl space-y-5 pb-24">
      <header className="rounded-[2rem] bg-white p-6 shadow-sm ring-1 ring-gray-100">
        <div className="flex items-start justify-between gap-4">
          <div>
            <p className="text-sm font-black uppercase text-[#0F766E]">Coach Impulse</p>
            <h1 className="mt-2 text-4xl font-black tracking-normal text-gray-950">Erinnerungen</h1>
            <p className="mt-3 max-w-2xl text-sm font-semibold text-gray-400">
              Kleine Push-Impulse für Wasser, geplante Snacks und Bewegung im Arbeitsalltag.
            </p>
          </div>
          <BellAlertIcon className="h-10 w-10 text-[#0F766E]" />
        </div>
      </header>

      <section className="rounded-[2rem] bg-white p-6 shadow-sm ring-1 ring-gray-100">
        <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
          <div>
            <h2 className="text-xl font-black text-gray-950">Benachrichtigungen</h2>
            <p className="mt-1 text-sm font-semibold text-gray-400">{permissionLabel(permission)}</p>
          </div>
          <div className="flex flex-wrap gap-3">
            <button
              type="button"
              onClick={() => void requestPermission()}
              className="rounded-full bg-gray-950 px-5 py-3 text-sm font-black text-white"
            >
              Berechtigung anfragen
            </button>
            <button
              type="button"
              disabled={permission !== "granted"}
              onClick={() => persist({ ...settings, enabled: !settings.enabled })}
              className={`rounded-full px-5 py-3 text-sm font-black disabled:opacity-40 ${
                settings.enabled ? "bg-emerald-600 text-white" : "bg-gray-100 text-gray-950"
              }`}
            >
              {settings.enabled ? "Aktiv" : "Pausiert"}
            </button>
          </div>
        </div>
      </section>

      <div className="grid gap-4 lg:grid-cols-3">
        {(Object.keys(settings.rules) as ReminderKind[]).map((kind) => {
          const meta = reminderMeta[kind];
          const rule = settings.rules[kind];
          return (
            <section key={kind} className="rounded-[2rem] bg-white p-5 shadow-sm ring-1 ring-gray-100">
              <div className="flex items-start gap-3">
                <meta.icon className={`h-8 w-8 ${meta.color}`} />
                <div>
                  <h2 className="text-xl font-black text-gray-950">{meta.title}</h2>
                  <p className="mt-1 text-sm font-semibold text-gray-400">{meta.description}</p>
                </div>
              </div>

              <label className="mt-5 flex items-center justify-between rounded-2xl bg-gray-50 px-4 py-3 text-sm font-black text-gray-950">
                Aktivieren
                <input
                  type="checkbox"
                  checked={rule.enabled}
                  onChange={(event) => updateRule(kind, { enabled: event.target.checked })}
                />
              </label>

              <div className="mt-4 grid grid-cols-2 gap-2">
                <label className="text-xs font-black uppercase text-gray-400">
                  Von
                  <input
                    type="time"
                    value={rule.startTime}
                    onChange={(event) => updateRule(kind, { startTime: event.target.value })}
                    className="mt-1 w-full rounded-2xl border border-gray-200 px-3 py-2 text-sm text-gray-950"
                  />
                </label>
                <label className="text-xs font-black uppercase text-gray-400">
                  Bis
                  <input
                    type="time"
                    value={rule.endTime}
                    onChange={(event) => updateRule(kind, { endTime: event.target.value })}
                    className="mt-1 w-full rounded-2xl border border-gray-200 px-3 py-2 text-sm text-gray-950"
                  />
                </label>
              </div>

              <label className="mt-4 block text-xs font-black uppercase text-gray-400">
                Intervall Minuten
                <input
                  type="number"
                  min={15}
                  step={15}
                  value={rule.intervalMinutes}
                  onChange={(event) => updateRule(kind, { intervalMinutes: Number(event.target.value) || 60 })}
                  className="mt-1 w-full rounded-2xl border border-gray-200 px-3 py-2 text-sm text-gray-950"
                />
              </label>

              <label className="mt-4 block text-xs font-black uppercase text-gray-400">
                Nachricht
                <textarea
                  value={rule.message}
                  onChange={(event) => updateRule(kind, { message: event.target.value })}
                  className="mt-1 min-h-24 w-full rounded-2xl border border-gray-200 px-3 py-2 text-sm font-semibold normal-case text-gray-950"
                />
              </label>

              <button
                type="button"
                disabled={permission !== "granted"}
                onClick={() => void sendTest(kind)}
                className="mt-4 w-full rounded-full bg-gray-100 px-4 py-3 text-sm font-black text-gray-950 disabled:opacity-40"
              >
                Test senden
              </button>
            </section>
          );
        })}
      </div>

      {saved ? (
        <div className="fixed bottom-24 left-1/2 z-50 flex -translate-x-1/2 items-center gap-2 rounded-full bg-emerald-600 px-5 py-3 text-sm font-black text-white shadow-lg">
          <CheckCircleIcon className="h-5 w-5" />
          Gespeichert
        </div>
      ) : null}
    </div>
  );
}