import React, { useState } from 'react';
import { useAuth } from '../contexts/AuthContext';
import { useLanguage } from '../contexts/LanguageContext';
import { t } from '../i18n/translations';
import { ArrowLeft } from 'lucide-react';

export function RegisterPage() {
  const { language } = useLanguage();
  const { register, completeRegistration } = useAuth();
  const [step, setStep] = useState<'register' | 'setup-otp' | 'verify-otp'>('register');
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const [confirmPassword, setConfirmPassword] = useState('');
  const [otpCode, setOtpCode] = useState('');
  const [userID, setUserID] = useState('');
  const [otpSecret, setOtpSecret] = useState('');
  const [qrCodeURL, setQrCodeURL] = useState('');
  const [error, setError] = useState('');
  const [loading, setLoading] = useState(false);

  const handleRegister = async (e: React.FormEvent) => {
    e.preventDefault();
    setError('');

    if (password !== confirmPassword) {
      setError(t('passwordMismatch', language));
      return;
    }

    if (password.length < 6) {
      setError(t('passwordTooShort', language));
      return;
    }

    setLoading(true);

    const result = await register(email, password);
    
    if (result.success && result.userID) {
      setUserID(result.userID);
      setOtpSecret(result.otpSecret || '');
      setQrCodeURL(result.qrCodeURL || '');
      setStep('setup-otp');
    } else {
      setError(result.message || t('registrationFailed', language));
    }
    
    setLoading(false);
  };

  const handleSetupComplete = () => {
    setStep('verify-otp');
  };

  const handleOTPVerify = async (e: React.FormEvent) => {
    e.preventDefault();
    setError('');
    setLoading(true);

    const result = await completeRegistration(userID, otpCode);
    
    if (!result.success) {
      setError(result.message || t('registrationFailed', language));
    }
    // 成功的话AuthContext会自动处理登录状态
    
    setLoading(false);
  };

  const copyToClipboard = (text: string) => {
    navigator.clipboard.writeText(text);
  };

  return (
    <div className="min-h-screen flex items-center justify-center" style={{ background: '#0B0E11' }}>
      <div className="w-full max-w-md">
        {/* Back to Home */}
        {step === 'register' && (
          <button
            onClick={() => {
              window.history.pushState({}, '', '/');
              window.dispatchEvent(new PopStateEvent('popstate'));
            }}
            className="flex items-center gap-2 mb-6 text-sm hover:text-[#F0B90B] transition-colors"
            style={{ color: '#848E9C' }}
          >
            <ArrowLeft className="w-4 h-4" />
            返回首页
          </button>
        )}

        {/* Logo */}
        <div className="text-center mb-8">
          <div className="w-16 h-16 mx-auto mb-4 flex items-center justify-center">
            <img src="/icons/nofx.svg?v=2" alt="NOFX" className="w-16 h-16" />
          </div>
          <h1 className="text-2xl font-bold" style={{ color: '#EAECEF' }}>
            {t('appTitle', language)}
          </h1>
          <p className="text-sm mt-2" style={{ color: '#848E9C' }}>
            {step === 'register' && t('registerTitle', language)}
            {step === 'setup-otp' && t('setupTwoFactor', language)}
            {step === 'verify-otp' && t('verifyOTP', language)}
          </p>
        </div>

        {/* Registration Form */}
        <div className="rounded-lg p-6" style={{ background: '#1E2329', border: '1px solid #2B3139' }}>
          {step === 'register' && (
            <form onSubmit={handleRegister} className="space-y-4">
              <div>
                <label className="block text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                  {t('email', language)}
                </label>
                <input
                  type="email"
                  value={email}
                  onChange={(e) => setEmail(e.target.value)}
                  className="w-full px-3 py-2 rounded"
                  style={{ background: '#0B0E11', border: '1px solid #2B3139', color: '#EAECEF' }}
                  placeholder={t('emailPlaceholder', language)}
                  required
                />
              </div>

              <div>
                <label className="block text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                  {t('password', language)}
                </label>
                <input
                  type="password"
                  value={password}
                  onChange={(e) => setPassword(e.target.value)}
                  className="w-full px-3 py-2 rounded"
                  style={{ background: '#0B0E11', border: '1px solid #2B3139', color: '#EAECEF' }}
                  placeholder={t('passwordPlaceholder', language)}
                  required
                />
              </div>

              <div>
                <label className="block text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                  {t('confirmPassword', language)}
                </label>
                <input
                  type="password"
                  value={confirmPassword}
                  onChange={(e) => setConfirmPassword(e.target.value)}
                  className="w-full px-3 py-2 rounded"
                  style={{ background: '#0B0E11', border: '1px solid #2B3139', color: '#EAECEF' }}
                  placeholder={t('confirmPasswordPlaceholder', language)}
                  required
                />
              </div>

              {error && (
                <div className="text-sm px-3 py-2 rounded" style={{ background: 'rgba(246, 70, 93, 0.1)', color: '#F6465D' }}>
                  {error}
                </div>
              )}

              <button
                type="submit"
                disabled={loading}
                className="w-full px-4 py-2 rounded text-sm font-semibold transition-all hover:scale-105 disabled:opacity-50"
                style={{ background: '#F0B90B', color: '#000' }}
              >
                {loading ? t('loading', language) : t('registerButton', language)}
              </button>
            </form>
          )}

          {step === 'setup-otp' && (
            <div className="space-y-4">
              <div className="text-center">
                <div className="text-4xl mb-2">📱</div>
                <h3 className="text-lg font-semibold mb-2" style={{ color: '#EAECEF' }}>
                  {t('setupTwoFactor', language)}
                </h3>
                <p className="text-sm" style={{ color: '#848E9C' }}>
                  {t('setupTwoFactorDesc', language)}
                </p>
              </div>

              <div className="space-y-3">
                <div className="p-3 rounded" style={{ background: '#0B0E11', border: '1px solid #2B3139' }}>
                  <p className="text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                    {t('step1Title', language)}
                  </p>
                  <p className="text-xs" style={{ color: '#848E9C' }}>
                    {t('step1Desc', language)}
                  </p>
                </div>

                <div className="p-3 rounded" style={{ background: '#0B0E11', border: '1px solid #2B3139' }}>
                  <p className="text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                    {t('step2Title', language)}
                  </p>
                  <p className="text-xs mb-2" style={{ color: '#848E9C' }}>
                    {t('step2Desc', language)}
                  </p>
                  
                  {qrCodeURL && (
                    <div className="mt-2">
                      <p className="text-xs mb-2" style={{ color: '#848E9C' }}>{t('qrCodeHint', language)}</p>
                      <div className="bg-white p-2 rounded text-center">
                        <img src={`https://api.qrserver.com/v1/create-qr-code/?size=150x150&data=${encodeURIComponent(qrCodeURL)}`} 
                             alt="QR Code" className="mx-auto" />
                      </div>
                    </div>
                  )}
                  
                  <div className="mt-2">
                    <p className="text-xs mb-1" style={{ color: '#848E9C' }}>{t('otpSecret', language)}</p>
                    <div className="flex items-center gap-2">
                      <code className="flex-1 px-2 py-1 text-xs rounded font-mono" 
                            style={{ background: '#2B3139', color: '#EAECEF' }}>
                        {otpSecret}
                      </code>
                      <button
                        onClick={() => copyToClipboard(otpSecret)}
                        className="px-2 py-1 text-xs rounded"
                        style={{ background: '#F0B90B', color: '#000' }}
                      >
                        {t('copy', language)}
                      </button>
                    </div>
                  </div>
                </div>

                <div className="p-3 rounded" style={{ background: '#0B0E11', border: '1px solid #2B3139' }}>
                  <p className="text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                    {t('step3Title', language)}
                  </p>
                  <p className="text-xs" style={{ color: '#848E9C' }}>
                    {t('step3Desc', language)}
                  </p>
                </div>
              </div>

              <button
                onClick={handleSetupComplete}
                className="w-full px-4 py-2 rounded text-sm font-semibold transition-all hover:scale-105"
                style={{ background: '#F0B90B', color: '#000' }}
              >
                {t('setupCompleteContinue', language)}
              </button>
            </div>
          )}

          {step === 'verify-otp' && (
            <form onSubmit={handleOTPVerify} className="space-y-4">
              <div className="text-center mb-4">
                <div className="text-4xl mb-2">🔐</div>
                <p className="text-sm" style={{ color: '#848E9C' }}>
                  {t('enterOTPCode', language)}<br />
                  {t('completeRegistrationSubtitle', language)}
                </p>
              </div>

              <div>
                <label className="block text-sm font-semibold mb-2" style={{ color: '#EAECEF' }}>
                  {t('otpCode', language)}
                </label>
                <input
                  type="text"
                  value={otpCode}
                  onChange={(e) => setOtpCode(e.target.value.replace(/\D/g, '').slice(0, 6))}
                  className="w-full px-3 py-2 rounded text-center text-2xl font-mono"
                  style={{ background: '#0B0E11', border: '1px solid #2B3139', color: '#EAECEF' }}
                  placeholder={t('otpPlaceholder', language)}
                  maxLength={6}
                  required
                />
              </div>

              {error && (
                <div className="text-sm px-3 py-2 rounded" style={{ background: 'rgba(246, 70, 93, 0.1)', color: '#F6465D' }}>
                  {error}
                </div>
              )}

              <div className="flex gap-3">
                <button
                  type="button"
                  onClick={() => setStep('setup-otp')}
                  className="flex-1 px-4 py-2 rounded text-sm font-semibold"
                  style={{ background: '#2B3139', color: '#848E9C' }}
                >
                  {t('back', language)}
                </button>
                <button
                  type="submit"
                  disabled={loading || otpCode.length !== 6}
                  className="flex-1 px-4 py-2 rounded text-sm font-semibold transition-all hover:scale-105 disabled:opacity-50"
                  style={{ background: '#F0B90B', color: '#000' }}
                >
                  {loading ? t('loading', language) : t('completeRegistration', language)}
                </button>
              </div>
            </form>
          )}
        </div>

        {/* Login Link */}
        {step === 'register' && (
          <div className="text-center mt-6">
            <p className="text-sm" style={{ color: '#848E9C' }}>
              已有账户？{' '}
              <button
                onClick={() => {
                  window.history.pushState({}, '', '/login');
                  window.dispatchEvent(new PopStateEvent('popstate'));
                }}
                className="font-semibold hover:underline"
                style={{ color: '#F0B90B' }}
              >
                立即登录
              </button>
            </p>
          </div>
        )}
      </div>
    </div>
  );
}