import React, { useState } from 'react';
import { Link, useNavigate } from 'react-router-dom';
import { Input, Button, message, Modal, Alert } from 'antd';
import { MailOutlined, LockOutlined, UserOutlined, SafetyOutlined, ExclamationCircleOutlined, CheckCircleOutlined } from '@ant-design/icons';
import { hashPassword } from '../../utils/crypto';
import './RegisterPage.css';

const baseURL = 'http://10.126.59.25:8082';

const RegisterPage = () => {
  const [formData, setFormData] = useState({
    username: '',
    email: '',
    emailCode: '',
    password: '',
    confirmPassword: ''
  });

  const [errors, setErrors] = useState({
    username: '',
    email: '',
    emailCode: '',
    password: '',
    confirmPassword: ''
  });

  const [emailCodeSent, setEmailCodeSent] = useState(false);
  const [countdown, setCountdown] = useState(0);
  const [sendingCode, setSendingCode] = useState(false);
  const [isLoading, setIsLoading] = useState(false);
  const [errorModal, setErrorModal] = useState({
    visible: false,
    title: '',
    content: ''
  });
  const [successAlert, setSuccessAlert] = useState({
    visible: false,
    message: ''
  });
  const [emailCodeSuccessAlert, setEmailCodeSuccessAlert] = useState({
    visible: false,
    message: ''
  });

  const navigate = useNavigate();

  // 显示错误弹窗
  const showErrorModal = (title, content) => {
    setErrorModal({
      visible: true,
      title: title,
      content: content
    });
  };

  // 关闭错误弹窗
  const closeErrorModal = () => {
    setErrorModal({
      visible: false,
      title: '',
      content: ''
    });
  };

  // 显示成功提示
  const showSuccessAlert = (message) => {
    setSuccessAlert({
      visible: true,
      message: message
    });
    
    // 3秒后自动隐藏
    setTimeout(() => {
      setSuccessAlert({
        visible: false,
        message: ''
      });
    }, 3000);
  };

  // 显示邮件验证码发送成功提示
  const showEmailCodeSuccessAlert = (message) => {
    setEmailCodeSuccessAlert({
      visible: true,
      message: message
    });
    
    // 5秒后自动隐藏
    setTimeout(() => {
      setEmailCodeSuccessAlert({
        visible: false,
        message: ''
      });
    }, 5000);
  };

  // 倒计时效果
  React.useEffect(() => {
    let timer;
    if (countdown > 0) {
      timer = setTimeout(() => {
        setCountdown(countdown - 1);
      }, 1000);
    }
    return () => clearTimeout(timer);
  }, [countdown]);

  // 发送邮箱验证码
  const sendEmailCode = async () => {
    // 验证邮箱格式
    if (!formData.email || typeof formData.email !== 'string' || !formData.email.trim()) {
      setErrors(prev => ({
        ...prev,
        email: '请先输入邮箱地址'
      }));
      return;
    }
    
    if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(formData.email)) {
      setErrors(prev => ({
        ...prev,
        email: '请输入有效的邮箱地址'
      }));
      return;
    }

    setSendingCode(true);
    
    try {
      // 调用后端API发送验证码
      const response = await fetch(baseURL + '/send-verification-code', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          email: formData.email,
          verification_type: 'register'
        })
      });
      
      if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
      }
      
      const result = await response.json();
      
      if (result.success) {
        showEmailCodeSuccessAlert('验证码已发送到您的邮箱');
        setEmailCodeSent(true);
        setCountdown(60); // 60秒倒计时
        
        // 清除邮箱错误提示
        setErrors(prev => ({
          ...prev,
          email: ''
        }));
      } else {
        // 根据具体错误信息进行处理
        const errorMessage = result.message || '发送验证码失败，请稍后再试';
        
        if (errorMessage.includes('邮箱') && (errorMessage.includes('已注册') || errorMessage.includes('已存在'))) {
          setErrors(prev => ({
            ...prev,
            email: errorMessage
          }));
        } else {
          showErrorModal('发送验证码失败', errorMessage);
        }
      }
      
    } catch (error) {
      console.error('发送验证码失败:', error);
      
      // 根据错误类型显示不同的错误信息
      if (error.name === 'TypeError' && error.message.includes('Failed to fetch')) {
        showErrorModal('网络连接失败', '无法连接到服务器，请检查您的网络连接后重试。如果问题持续存在，请联系客服。');
      } else if (error.message.includes('HTTP 500')) {
        showErrorModal('服务器错误', '服务器出现了内部错误，请稍后重试。如果问题持续存在，请联系客服。');
      } else if (error.message.includes('HTTP 429')) {
        showErrorModal('发送频率限制', '验证码发送过于频繁，请稍后再试。为了防止垃圾邮件，系统限制了发送频率。');
      } else if (error.message.includes('HTTP 400')) {
        showErrorModal('请求错误', '邮箱格式错误，请检查邮箱地址是否正确。');
      } else {
        showErrorModal('发送失败', '发送验证码失败，请稍后重试。如果问题持续存在，请联系客服。');
      }
    } finally {
      setSendingCode(false);
    }
  };

  const handleInputChange = (field) => (e) => {
    const value = e.target.value;
    setFormData(prev => ({
      ...prev,
      [field]: value
    }));
    
    // 清除对应字段的错误提示
    if (errors[field]) {
      setErrors(prev => ({
        ...prev,
        [field]: ''
      }));
    }
  };

  const handlePasswordChange = (e) => {
    const value = e.target.value;
    setFormData(prev => ({
      ...prev,
      password: value
    }));
    
    // 清除密码错误提示
    if (errors.password) {
      setErrors(prev => ({
        ...prev,
        password: ''
      }));
    }
  };

  const handleConfirmPasswordChange = (e) => {
    const value = e.target.value;
    setFormData(prev => ({
      ...prev,
      confirmPassword: value
    }));
    
    // 清除确认密码错误提示
    if (errors.confirmPassword) {
      setErrors(prev => ({
        ...prev,
        confirmPassword: ''
      }));
    }
  };

  const validateForm = () => {
    const newErrors = {
      username: '',
      email: '',
      emailCode: '',
      password: '',
      confirmPassword: ''
    };
    
    let hasError = false;
    
    // 验证用户名
    if (!formData.username || typeof formData.username !== 'string' || !formData.username.trim()) {
      newErrors.username = '请输入用户名';
      hasError = true;
    } else if (formData.username.length < 2) {
      newErrors.username = '用户名至少2个字符';
      hasError = true;
    } else if (formData.username.length > 20) {
      newErrors.username = '用户名不能超过20个字符';
      hasError = true;
    }
    
    // 验证邮箱
    if (!formData.email || typeof formData.email !== 'string' || !formData.email.trim()) {
      newErrors.email = '请输入邮箱地址';
      hasError = true;
    } else if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(formData.email)) {
      newErrors.email = '请输入有效的邮箱地址';
      hasError = true;
    }
    
    // 验证邮箱验证码
    if (!formData.emailCode || typeof formData.emailCode !== 'string' || !formData.emailCode.trim()) {
      newErrors.emailCode = '请输入邮箱验证码';
      hasError = true;
    } else if (formData.emailCode.length !== 6 || !/^\d{6}$/.test(formData.emailCode)) {
      newErrors.emailCode = '请输入6位数字验证码';
      hasError = true;
    }
    
    // 验证密码
    if (!formData.password || typeof formData.password !== 'string' || !formData.password.trim()) {
      newErrors.password = '请输入密码';
      hasError = true;
    } else if (formData.password.length < 6) {
      newErrors.password = '密码长度至少6位';
      hasError = true;
    } else if (formData.password.length > 20) {
      newErrors.password = '密码长度不能超过20位';
      hasError = true;
    }
    
    // 验证确认密码
    if (!formData.confirmPassword || typeof formData.confirmPassword !== 'string' || !formData.confirmPassword.trim()) {
      newErrors.confirmPassword = '请确认密码';
      hasError = true;
    } else if (formData.password !== formData.confirmPassword) {
      newErrors.confirmPassword = '两次输入的密码不一致';
      hasError = true;
    }
    
    setErrors(newErrors);
    return !hasError;
  };

  const handleSubmit = async (e) => {
    e.preventDefault();
    
    // 验证表单
    if (!validateForm()) {
      return;
    }
    
    setIsLoading(true);
    
    try {
      // 调用后端API进行注册
      const registerResponse = await fetch(baseURL + '/register', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          username: formData.username,
          email: formData.email,
          password: hashPassword(formData.password), // 前端加密密码
          verification_code: hashPassword(formData.emailCode) // 前端加密验证码
        })
      });
      
      if (!registerResponse.ok) {
        throw new Error(`HTTP ${registerResponse.status}: ${registerResponse.statusText}`);
      }
      
      const registerResult = await registerResponse.json();
      
      if (registerResult.success) {
        showSuccessAlert('注册成功！欢迎加入小红书，正在跳转到登录页面...');
        // 清空表单数据
        setFormData({
          username: '',
          email: '',
          emailCode: '',
          password: '',
          confirmPassword: ''
        });
        setErrors({
          username: '',
          email: '',
          emailCode: '',
          password: '',
          confirmPassword: ''
        });
        // 延迟跳转到登录页面，让用户看到成功提示
        setTimeout(() => {
          navigate('/login');
        }, 2000);
      } else {
        // 处理不同的注册失败情况
        const errorMessage = registerResult.message || '注册失败，请稍后再试';
        
        // 如果是邮箱已存在的错误，将错误显示在邮箱字段下方
        if (errorMessage.includes('邮箱') && (errorMessage.includes('已存在') || errorMessage.includes('已注册'))) {
          setErrors(prev => ({
            ...prev,
            email: errorMessage
          }));
        } 
        // 如果是用户名已存在的错误，将错误显示在用户名字段下方
        else if (errorMessage.includes('用户名') && (errorMessage.includes('已存在') || errorMessage.includes('已被使用'))) {
          setErrors(prev => ({
            ...prev,
            username: errorMessage
          }));
        } 
        else {
          // 其他错误显示在消息框中
          message.error(errorMessage);
        }
      }
      
    } catch (error) {
      console.error('注册失败:', error);
      
      // 根据错误类型显示不同的错误信息
      if (error.name === 'TypeError' && error.message.includes('Failed to fetch')) {
        showErrorModal('网络连接失败', '无法连接到服务器，请检查您的网络连接后重试。如果问题持续存在，请联系客服。');
      } else if (error.message.includes('HTTP 500')) {
        showErrorModal('服务器内部错误', '服务器出现了内部错误，请稍后重试或联系客服。技术团队已收到通知。');
      } else if (error.message.includes('HTTP 400')) {
        showErrorModal('请求参数错误', '请求参数有误，请检查您输入的信息是否正确。');
      } else if (error.message.includes('HTTP 409')) {
        showErrorModal('用户信息冲突', '您输入的邮箱或用户名可能已被其他用户使用，请尝试使用其他邮箱或用户名。');
      } else if (error.message.includes('HTTP')) {
        showErrorModal('请求失败', `请求失败 (${error.message})，请稍后重试。如果问题持续存在，请联系客服。`);
      } else {
        showErrorModal('注册失败', '注册过程中发生未知错误，请稍后重试。如果问题持续存在，请联系客服。');
      }
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <div className="register-container">
      <div className="register-background"></div>
      
      {isLoading && (
        <div className="loading-overlay">
          <div className="loading-content">
            <div className="loading-spinner-large"></div>
            <p className="loading-text">正在注册...</p>
          </div>
        </div>
      )}
      
      <div className="register-content">
        <div className="register-card">
          {/* 成功提示 */}
          {successAlert.visible && (
            <div style={{ marginBottom: '16px' }}>
              <Alert
                message={successAlert.message}
                type="success"
                icon={<CheckCircleOutlined />}
                showIcon
                closable
                onClose={() => setSuccessAlert({ visible: false, message: '' })}
                style={{
                  borderRadius: '8px',
                  border: '1px solid #b7eb8f',
                  backgroundColor: '#f6ffed'
                }}
              />
            </div>
          )}

          {/* 邮件验证码发送成功提示 */}
          {emailCodeSuccessAlert.visible && (
            <div style={{ marginBottom: '16px' }}>
              <Alert
                message={emailCodeSuccessAlert.message}
                type="success"
                icon={<CheckCircleOutlined />}
                showIcon
                closable
                onClose={() => setEmailCodeSuccessAlert({ visible: false, message: '' })}
                style={{
                  borderRadius: '8px',
                  border: '1px solid #b7eb8f',
                  backgroundColor: '#f6ffed'
                }}
              />
            </div>
          )}
          
          <div className="register-header">
            <h1 className="register-title">加入小红书</h1>
            <p className="register-subtitle">发现美好生活，分享精彩瞬间</p>
          </div>

          <form className="register-form" onSubmit={handleSubmit}>
            <div className="form-group">
              <Input
                type="text"
                id="username"
                name="username"
                className={`form-input ${errors.username ? 'input-error' : ''}`}
                placeholder="请输入用户名"
                value={formData.username}
                onChange={handleInputChange('username')}
                prefix={<UserOutlined />}
                size="large"
                title=""
                status={errors.username ? 'error' : ''}
              />
              {errors.username && (
                <div className="error-message">
                  {errors.username}
                </div>
              )}
            </div>

            <div className="form-group">
              <Input
                type="email"
                id="email"
                name="email"
                className={`form-input ${errors.email ? 'input-error' : ''}`}
                placeholder="请输入邮箱地址"
                value={formData.email}
                onChange={handleInputChange('email')}
                prefix={<MailOutlined />}
                size="large"
                title=""
                status={errors.email ? 'error' : ''}
              />
              {errors.email && (
                <div className="error-message">
                  {errors.email}
                </div>
              )}
            </div>

            <div className="form-group">
              <div className="email-code-wrapper">
                <Input
                  type="text"
                  id="emailCode"
                  name="emailCode"
                  className={`form-input email-code-input ${errors.emailCode ? 'input-error' : ''}`}
                  placeholder="请输入6位验证码"
                  value={formData.emailCode}
                  onChange={handleInputChange('emailCode')}
                  prefix={<SafetyOutlined />}
                  maxLength={6}
                  size="large"
                  title=""
                  status={errors.emailCode ? 'error' : ''}
                />
                <Button
                  type="primary"
                  className="send-code-button"
                  onClick={sendEmailCode}
                  loading={sendingCode}
                  disabled={countdown > 0 || !formData.email || sendingCode}
                  size="large"
                >
                  {countdown > 0 ? `${countdown}s后重发` : (emailCodeSent ? '重新发送' : '发送验证码')}
                </Button>
              </div>
              {errors.emailCode && (
                <div className="error-message">
                  {errors.emailCode}
                </div>
              )}
            </div>

            <div className="form-group">
              <Input.Password
                id="password"
                name="password"
                className={`form-input ${errors.password ? 'input-error' : ''}`}
                placeholder="请输入密码"
                value={formData.password}
                onChange={handlePasswordChange}
                prefix={<LockOutlined />}
                size="large"
                title=""
                status={errors.password ? 'error' : ''}
              />
              {errors.password && (
                <div className="error-message">
                  {errors.password}
                </div>
              )}
            </div>

            <div className="form-group">
              <Input.Password
                id="confirmPassword"
                name="confirmPassword"
                className={`form-input ${errors.confirmPassword ? 'input-error' : ''}`}
                placeholder="请确认密码"
                value={formData.confirmPassword}
                onChange={handleConfirmPasswordChange}
                prefix={<LockOutlined />}
                size="large"
                title=""
                status={errors.confirmPassword ? 'error' : ''}
              />
              {errors.confirmPassword && (
                <div className="error-message">
                  {errors.confirmPassword}
                </div>
              )}
            </div>

            <button
              type="submit"
              className={`register-button ${isLoading ? 'loading' : ''}`}
              disabled={isLoading}
            >
              {isLoading ? (
                <>
                  <div className="loading-spinner"></div>
                  注册中...
                </>
              ) : (
                '立即注册'
              )}
            </button>
          </form>

          <div className="login-link">
            <p>已有账户？ <Link to="/login">立即登录</Link></p>
          </div>
        </div>
      </div>

      {/* 错误弹窗 */}
      <Modal
        title={
          <div style={{ display: 'flex', alignItems: 'center', gap: '8px' }}>
            <ExclamationCircleOutlined style={{ color: '#ff4d4f', fontSize: '18px' }} />
            {errorModal.title}
          </div>
        }
        open={errorModal.visible}
        onOk={closeErrorModal}
        onCancel={closeErrorModal}
        okText="我知道了"
        cancelButtonProps={{ style: { display: 'none' } }}
        centered
        className="error-modal"
      >
        <div style={{ padding: '16px 0', fontSize: '14px', lineHeight: '1.6' }}>
          {errorModal.content}
        </div>
      </Modal>
    </div>
  );
};

export default RegisterPage;