"use client";

import { useState } from "react";
import { useRouter } from "next/navigation";
import Link from "next/link";
import { createClient } from "@/lib/supabase/client";
import { formatMessage } from "@/lib/i18n/shared";
import { useDict } from "@/components/i18n/LocaleProvider";
import LanguageSwitcher from "@/components/i18n/LanguageSwitcher";
import type { Dict } from "@/lib/i18n/shared";

function authErrorMessage(dict: Dict, message: string): string {
  if (/invalid login credentials/i.test(message))
    return dict.login.errorInvalidCredentials;
  if (/email not confirmed/i.test(message))
    return dict.login.errorEmailNotConfirmed;
  if (/cancelled|aborted|NotAllowedError/i.test(message))
    return dict.login.errorPasskeyCancelled;
  return formatMessage(dict.login.errorGeneric, { message });
}

export default function LoginPage() {
  const router = useRouter();
  const supabase = createClient();
  const dict = useDict();
  const [email, setEmail] = useState("");
  const [password, setPassword] = useState("");
  const [error, setError] = useState<string | null>(null);
  const [busy, setBusy] = useState(false);

  async function redirectByRole(userId: string) {
    const { data: profile } = await supabase
      .from("profiles")
      .select("role")
      .eq("id", userId)
      .single();
    router.replace(profile?.role === "admin" ? "/admin" : "/intern");
    router.refresh();
  }

  async function signInWithPassword(e: React.FormEvent) {
    e.preventDefault();
    setError(null);
    setBusy(true);
    const { data, error } = await supabase.auth.signInWithPassword({
      email,
      password,
    });
    if (error || !data.user) {
      setError(authErrorMessage(dict, error?.message ?? "Unbekannter Fehler"));
      setBusy(false);
      return;
    }

    const { data: profile } = await supabase
      .from("profiles")
      .select("role, password_auth_enabled")
      .eq("id", data.user.id)
      .single();
    if (profile?.password_auth_enabled === false) {
      await supabase.auth.signOut();
      setError(dict.login.errorPasswordDisabled);
      setBusy(false);
      return;
    }
    router.replace(profile?.role === "admin" ? "/admin" : "/intern");
    router.refresh();
  }

  async function signInWithPasskey() {
    setError(null);
    setBusy(true);
    try {
      const { data, error } = await supabase.auth.signInWithPasskey();
      if (error || !data?.user) {
        setError(
          authErrorMessage(dict, error?.message ?? "Passkey-Anmeldung fehlgeschlagen")
        );
        setBusy(false);
        return;
      }
      await redirectByRole(data.user.id);
    } catch (err) {
      setError(authErrorMessage(dict, err instanceof Error ? err.message : String(err)));
      setBusy(false);
    }
  }

  return (
    <div className="flex-1 flex items-center justify-center p-4">
      <div className="card w-full max-w-sm">
        <div className="flex justify-between items-center mb-4">
          <h1 className="text-xl font-bold text-[var(--c-primary)]">
            {dict.login.title}
          </h1>
          <LanguageSwitcher variant="light" />
        </div>
        <form onSubmit={signInWithPassword} className="space-y-3">
          <div>
            <label className="label" htmlFor="email">
              {dict.common.email}
            </label>
            <input
              id="email"
              type="email"
              className="input"
              value={email}
              onChange={(e) => setEmail(e.target.value)}
              autoComplete="username webauthn"
              required
            />
          </div>
          <div>
            <label className="label" htmlFor="password">
              {dict.common.password}
            </label>
            <input
              id="password"
              type="password"
              className="input"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              autoComplete="current-password"
              required
            />
          </div>
          {error && <p className="text-sm text-[var(--c-del)]">{error}</p>}
          <button type="submit" className="btn btn-primary w-full" disabled={busy}>
            {dict.login.submit}
          </button>
        </form>

        <div className="my-4 flex items-center gap-3 text-xs text-gray-400">
          <span className="h-px flex-1 bg-gray-200" />
          {dict.login.or}
          <span className="h-px flex-1 bg-gray-200" />
        </div>

        <button
          type="button"
          onClick={signInWithPasskey}
          className="btn btn-neutral w-full"
          disabled={busy}
        >
          {dict.login.passkeyButton}
        </button>

        <p className="mt-4 text-center text-sm">
          <Link href="/" className="text-gray-500 hover:text-[var(--c-primary)]">
            {dict.login.backToMenu}
          </Link>
        </p>
      </div>
    </div>
  );
}