import { useState } from 'react';
import { useNavigate } from 'react-router-dom';
import { Lock, Mail, Phone, ChevronLeft, KeyRound } from 'lucide-react';
import { toast } from 'react-hot-toast';
import api from '../services/api';
import { useAdminAuthStore } from '../store/adminAuthStore';
import type { ApiResponse, AuthResponseData } from '../types/admin';

export default function Login() {
  const [loginMode, setLoginMode] = useState<'password' | 'otp'>('password');
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');

  const [phoneNumber, setPhoneNumber] = useState('');
  const [otpCode, setOtpCode] = useState('');
  const [otpSent, setOtpSent] = useState(false);

  const [isLoading, setIsLoading] = useState(false);
  const navigate = useNavigate();
  const setAuth = useAdminAuthStore((state) => state.setAuth);

  const handlePasswordLogin = async (e: React.FormEvent) => {
    e.preventDefault();
    setIsLoading(true);

    try {
      const response = await api.post<ApiResponse<AuthResponseData>>('/auth/admin-login', { email, password });
      if (response.data?.success && response.data.data) {
        setAuth(response.data.data.accessToken, response.data.data.user);
        toast.success('ورود با موفقیت انجام شد');
        navigate('/');
      } else {
        toast.error('اطلاعات ورود نامعتبر است');
      }
    } catch {
      // Toast notification is handled by api.ts interceptor
    } finally {
      setIsLoading(false);
    }
  };

  const handleSendOtp = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!phoneNumber || phoneNumber.length < 10) {
      toast.error('شماره موبایل معتبر وارد کنید');
      return;
    }
    setIsLoading(true);

    try {
      const response = await api.post<ApiResponse>('/auth/send-otp', { phoneNumber });
      if (response.data?.success) {
        toast.success(response.data.message || 'کد تایید پیامک شد');
        setOtpSent(true);
      }
    } catch {
      toast.error('خطا در ارسال کد تایید');
    } finally {
      setIsLoading(false);
    }
  };

  const handleVerifyOtp = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!otpCode || otpCode.length < 4) {
      toast.error('کد تایید معتبر وارد کنید');
      return;
    }
    setIsLoading(true);

    try {
      const response = await api.post<ApiResponse<AuthResponseData>>('/auth/verify-otp', { phoneNumber, code: otpCode });
      if (response.data?.success && response.data.data) {
        setAuth(response.data.data.accessToken, response.data.data.user);
        toast.success('ورود موفقیت‌آمیز بود');
        navigate('/');
      } else {
        toast.error('کد تایید نامعتبر است');
      }
    } catch {
      toast.error('کد تایید اشتباه یا منقضی شده است');
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <div className="min-h-screen bg-gray-50 flex flex-col justify-center py-12 sm:px-6 lg:px-8 font-vazir" dir="rtl">
      <div className="sm:mx-auto sm:w-full sm:max-w-md">
        <div className="w-20 h-20 bg-purple-600 rounded-2xl mx-auto flex items-center justify-center shadow-lg shadow-purple-200">
          <Lock className="w-10 h-10 text-white" />
        </div>
        <h2 className="mt-6 text-center text-3xl font-black text-gray-900">
          ورود به پنل مدیریت
        </h2>
        <p className="mt-2 text-center text-sm text-gray-600 font-bold">
          کانینا | لابراتوار تخصصی مکمل‌های درمانی حیوانات
        </p>
      </div>

      <div className="mt-8 sm:mx-auto sm:w-full sm:max-w-md">
        <div className="bg-white py-8 px-4 shadow-xl shadow-gray-100 sm:rounded-3xl sm:px-10 border border-gray-100">
          {/* Toggle Login Mode */}
          <div className="flex bg-gray-100 p-1 rounded-xl mb-6">
            <button
              type="button"
              onClick={() => { setLoginMode('password'); setOtpSent(false); }}
              className={`flex-1 py-2 text-xs font-black rounded-lg transition-all ${loginMode === 'password' ? 'bg-white text-purple-600 shadow-sm' : 'text-gray-500 hover:text-gray-900'}`}
            >
              ورود با رمز عبور
            </button>
            <button
              type="button"
              onClick={() => { setLoginMode('otp'); setOtpSent(false); }}
              className={`flex-1 py-2 text-xs font-black rounded-lg transition-all ${loginMode === 'otp' ? 'bg-white text-purple-600 shadow-sm' : 'text-gray-500 hover:text-gray-900'}`}
            >
              ورود با پیامک (OTP)
            </button>
          </div>

          {loginMode === 'password' ? (
            <form className="space-y-6" onSubmit={handlePasswordLogin}>
              <div>
                <label className="block text-sm font-black text-gray-700">آدرس ایمیل ادمین</label>
                <div className="mt-2 relative">
                  <div className="absolute inset-y-0 right-0 pl-3 flex items-center pr-3 pointer-events-none">
                    <Mail className="h-5 w-5 text-gray-400" />
                  </div>
                  <input
                    type="email"
                    required
                    value={email}
                    onChange={(e) => setEmail(e.target.value)}
                    className="block w-full pl-3 pr-10 py-3 border border-gray-200 rounded-xl focus:ring-purple-500 focus:border-purple-500 sm:text-sm bg-gray-50 font-bold transition-all"
                    placeholder="admin@canino-iran.com"
                    dir="ltr"
                  />
                </div>
              </div>

              <div>
                <label className="block text-sm font-black text-gray-700">رمز عبور</label>
                <div className="mt-2 relative">
                  <div className="absolute inset-y-0 right-0 pl-3 flex items-center pr-3 pointer-events-none">
                    <Lock className="h-5 w-5 text-gray-400" />
                  </div>
                  <input
                    type="password"
                    required
                    value={password}
                    onChange={(e) => setPassword(e.target.value)}
                    className="block w-full pl-3 pr-10 py-3 border border-gray-200 rounded-xl focus:ring-purple-500 focus:border-purple-500 sm:text-sm bg-gray-50 font-bold transition-all text-left"
                    placeholder="••••••••"
                    dir="ltr"
                  />
                </div>
              </div>

              <div>
                <button
                  type="submit"
                  disabled={isLoading}
                  className="w-full flex justify-center items-center gap-2 py-3 px-4 border border-transparent rounded-xl shadow-sm text-sm font-black text-white bg-purple-600 hover:bg-purple-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-purple-500 transition-all disabled:opacity-50 disabled:cursor-wait"
                >
                  {isLoading ? 'در حال ورود...' : 'ورود به سیستم'}
                  {!isLoading && <ChevronLeft className="w-5 h-5" />}
                </button>
              </div>
            </form>
          ) : (
            <div className="space-y-6">
              {!otpSent ? (
                <form className="space-y-6" onSubmit={handleSendOtp}>
                  <div>
                    <label className="block text-sm font-black text-gray-700">شماره تلفن همراه</label>
                    <div className="mt-2 relative">
                      <div className="absolute inset-y-0 right-0 pl-3 flex items-center pr-3 pointer-events-none">
                        <Phone className="h-5 w-5 text-gray-400" />
                      </div>
                      <input
                        type="tel"
                        required
                        value={phoneNumber}
                        onChange={(e) => setPhoneNumber(e.target.value)}
                        className="block w-full pl-3 pr-10 py-3 border border-gray-200 rounded-xl focus:ring-purple-500 focus:border-purple-500 sm:text-sm bg-gray-50 font-bold transition-all text-left"
                        placeholder="09123456789"
                        dir="ltr"
                      />
                    </div>
                  </div>

                  <button
                    type="submit"
                    disabled={isLoading}
                    className="w-full flex justify-center items-center gap-2 py-3 px-4 border border-transparent rounded-xl shadow-sm text-sm font-black text-white bg-purple-600 hover:bg-purple-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-purple-500 transition-all disabled:opacity-50 disabled:cursor-wait"
                  >
                    {isLoading ? 'در حال ارسال کد...' : 'ارسال کد تایید پیامکی'}
                    {!isLoading && <ChevronLeft className="w-5 h-5" />}
                  </button>
                </form>
              ) : (
                <form className="space-y-6" onSubmit={handleVerifyOtp}>
                  <div>
                    <div className="flex justify-between items-center mb-1">
                      <label className="block text-sm font-black text-gray-700">کد تایید ۵ رقمی</label>
                      <button
                        type="button"
                        onClick={() => setOtpSent(false)}
                        className="text-xs text-purple-600 font-bold hover:underline"
                      >
                        تغییر شماره
                      </button>
                    </div>
                    <div className="mt-2 relative">
                      <div className="absolute inset-y-0 right-0 pl-3 flex items-center pr-3 pointer-events-none">
                        <KeyRound className="h-5 w-5 text-gray-400" />
                      </div>
                      <input
                        type="text"
                        required
                        maxLength={6}
                        value={otpCode}
                        onChange={(e) => setOtpCode(e.target.value)}
                        className="block w-full pl-3 pr-10 py-3 border border-gray-200 rounded-xl focus:ring-purple-500 focus:border-purple-500 sm:text-sm bg-gray-50 font-bold transition-all text-center tracking-widest text-lg"
                        placeholder="12345"
                        dir="ltr"
                      />
                    </div>
                  </div>

                  <button
                    type="submit"
                    disabled={isLoading}
                    className="w-full flex justify-center items-center gap-2 py-3 px-4 border border-transparent rounded-xl shadow-sm text-sm font-black text-white bg-purple-600 hover:bg-purple-700 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-purple-500 transition-all disabled:opacity-50 disabled:cursor-wait"
                  >
                    {isLoading ? 'در حال تایید...' : 'تایید و ورود به پنل'}
                    {!isLoading && <ChevronLeft className="w-5 h-5" />}
                  </button>
                </form>
              )}
            </div>
          )}
        </div>
      </div>
    </div>
  );
}