"use client";

import { signIn } from "next-auth/react";
import { useRouter, useSearchParams } from "next/navigation";
import { Suspense, useState } from "react";
import { Lock, User, AlertCircle, LogIn } from "lucide-react";

export default function AdminLoginPage() {
  return (
    <Suspense
      fallback={
        <div className="min-h-[80vh] flex items-center justify-center text-brand-300">
          Yükleniyor...
        </div>
      }
    >
      <LoginForm />
    </Suspense>
  );
}

function LoginForm() {
  const router = useRouter();
  const params = useSearchParams();
  const callbackUrl = params.get("callbackUrl") || "/admin";

  const [username, setUsername] = useState("");
  const [password, setPassword] = useState("");
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);

  async function onSubmit(e: React.FormEvent) {
    e.preventDefault();
    setLoading(true);
    setError(null);

    const res = await signIn("credentials", {
      username,
      password,
      redirect: false,
    });

    setLoading(false);
    if (!res || res.error) {
      setError("Kullanıcı adı veya şifre hatalı.");
      return;
    }
    router.push(callbackUrl);
    router.refresh();
  }

  return (
    <div className="min-h-[80vh] flex items-center justify-center px-4 py-16">
      <div className="w-full max-w-md glass-strong rounded-2xl p-8 shadow-2xl">
        <div className="flex items-center gap-3 mb-6">
          <div className="w-12 h-12 rounded-xl bg-brand-700/40 flex items-center justify-center">
            <Lock className="w-6 h-6 text-brand-100" />
          </div>
          <div>
            <h1 className="text-2xl font-bold text-white">Admin Girişi</h1>
            <p className="text-sm text-brand-300/80">Yönetim paneline erişim</p>
          </div>
        </div>

        <form onSubmit={onSubmit} className="space-y-4">
          <div>
            <label className="block text-sm text-brand-200 mb-1">
              Kullanıcı Adı
            </label>
            <div className="relative">
              <User className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-brand-400" />
              <input
                type="text"
                value={username}
                onChange={(e) => setUsername(e.target.value)}
                className="w-full bg-brand-900/40 border border-brand-700/40 focus:border-brand-400 rounded-lg pl-10 pr-3 py-2.5 text-white outline-none transition"
                placeholder="admin"
                autoComplete="username"
                required
              />
            </div>
          </div>

          <div>
            <label className="block text-sm text-brand-200 mb-1">Şifre</label>
            <div className="relative">
              <Lock className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-brand-400" />
              <input
                type="password"
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                className="w-full bg-brand-900/40 border border-brand-700/40 focus:border-brand-400 rounded-lg pl-10 pr-3 py-2.5 text-white outline-none transition"
                placeholder="••••••••"
                autoComplete="current-password"
                required
              />
            </div>
          </div>

          {error && (
            <div className="flex items-start gap-2 p-3 rounded-lg bg-red-500/10 border border-red-500/30 text-red-200 text-sm">
              <AlertCircle className="w-4 h-4 mt-0.5 shrink-0" />
              <span>{error}</span>
            </div>
          )}

          <button
            type="submit"
            disabled={loading}
            className="btn-primary w-full justify-center disabled:opacity-60 disabled:cursor-not-allowed"
          >
            <LogIn className="w-4 h-4" />
            {loading ? "Giriş yapılıyor..." : "Giriş Yap"}
          </button>
        </form>

        <p className="mt-6 text-xs text-brand-400 text-center">
          Yalnızca yetkili yöneticiler erişebilir.
        </p>
      </div>
    </div>
  );
}