import React, { useState, useEffect } from 'react';
import { Link } from 'react-router-dom';
import { Input, Checkbox, Modal, Alert } from 'antd';
import { MailOutlined, LockOutlined, ExclamationCircleOutlined, CheckCircleOutlined } from '@ant-design/icons';
import { 
  getRememberedLoginInfo, 
  saveRememberedLoginInfo, 
  saveAuthInfo, 
  isLoggedIn 
} from '../../utils/auth';
import { hashPassword } from '../../utils/crypto';
import './LoginPage.css';

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

const LoginPage = () => {
  const [formData, setFormData] = useState({
    email: '',
    password: ''
  });

  const [rememberMe, setRememberMe] = useState(false);
  const [isLoading, setIsLoading] = useState(false);
  const [errors, setErrors] = useState({
    email: '',
    password: ''
  });
  const [errorModal, setErrorModal] = useState({
    visible: false,
    title: '',
    content: ''
  });
  const [successAlert, setSuccessAlert] = useState({
    visible: false,
    message: ''
  });

  // 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);
  };

  // 页面加载时检查是否有记住的登录信息
  useEffect(() => {
    // 检查是否已经登录
    if (isLoggedIn()) {
      // 如果已经有token，可以选择直接跳转到主页面
      // window.location.href = '/test-dashboard';
      console.log('用户已登录');
    }

    // 获取记住的登录信息
    const rememberedInfo = getRememberedLoginInfo();
    if (rememberedInfo.rememberMe && rememberedInfo.email) {
      setFormData({
        email: rememberedInfo.email,
        password: rememberedInfo.password
      });
      setRememberMe(true);
    }
  }, []);

  const handleEmailChange = (e) => {
    const value = e.target.value;
    setFormData(prev => ({
      ...prev,
      email: value
    }));
    
    // 清除邮箱错误提示
    if (errors.email) {
      setErrors(prev => ({
        ...prev,
        email: ''
      }));
    }
  };

  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 handleRememberMeChange = (e) => {
    const checked = e.target.checked;
    setRememberMe(checked);
    
    // 如果取消记住我，清除已保存的登录信息
    if (!checked) {
      saveRememberedLoginInfo('', '', false);
    }
  };

  const validateForm = () => {
    const newErrors = {
      email: '',
      password: ''
    };
    
    let hasError = false;
    
    // 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;
    }
    
    setErrors(newErrors);
    return !hasError;
  };

  const handleSubmit = async (e) => {
    e.preventDefault();
    
    // 验证表单
    if (!validateForm()) {
      return;
    }
    
    setIsLoading(true);
    
    try {
      // 发送登录请求到后端
      const response = await fetch(baseURL + '/login', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          email: formData.email, // 后端支持邮箱登录
          password: hashPassword(formData.password) // 前端加密密码
        })
      });
      
      const result = await response.json();
      
      if (result.success) {
        // 显示成功提示
        showSuccessAlert('登录成功！正在跳转...');
        
        // 保存认证信息
        saveAuthInfo(result.token, result.user, rememberMe);
        
        // 保存或清除记住的登录信息
        saveRememberedLoginInfo(formData.email, formData.password, rememberMe);
        
        // 延迟跳转，让用户看到成功提示
        setTimeout(() => {
          window.location.href = '/test-dashboard';
        }, 1500);
      } else {
        // 登录失败，显示错误信息
        let errorTitle = '登录失败';
        let errorContent = result.message || '登录失败，请检查您的邮箱和密码';
        
        // 根据错误类型提供更详细的信息
        if (result.message) {
          if (result.message.includes('邮箱') || result.message.includes('email')) {
            errorTitle = '邮箱验证失败';
            errorContent = '您输入的邮箱地址不存在或格式不正确，请检查后重试。';
          } else if (result.message.includes('密码') || result.message.includes('password')) {
            errorTitle = '密码验证失败';
            errorContent = '您输入的密码不正确，请检查后重试。如果忘记密码，请点击"忘记密码"进行重置。';
          } else if (result.message.includes('用户不存在')) {
            errorTitle = '用户不存在';
            errorContent = '该邮箱尚未注册，请先注册账户或检查邮箱地址是否正确。';
          } else if (result.message.includes('账户被锁定') || result.message.includes('locked')) {
            errorTitle = '账户被锁定';
            errorContent = '您的账户因安全原因被暂时锁定，请联系客服或稍后重试。';
          }
        }
        
        showErrorModal(errorTitle, errorContent);
      }
    } catch (error) {
      console.error('登录请求失败:', error);
      
      // 根据错误类型显示不同的错误信息
      if (error.name === 'TypeError' && error.message.includes('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.name === 'AbortError') {
        showErrorModal('请求超时', '请求超时，请检查网络连接后重试。');
      } else {
        showErrorModal('登录失败', '网络连接失败，请检查网络或稍后重试。如果问题持续存在，请联系客服。');
      }
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <div className="login-container">
      <div className="login-background"></div>
      
      {isLoading && (
        <div className="loading-overlay">
          <div className="loading-content">
            <div className="loading-spinner-large"></div>
            <p className="loading-text">正在登录...</p>
          </div>
        </div>
      )}
      
      <div className="login-content">
        <div className="login-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>
          )}
          
          <div className="login-header">
            <h1 className="login-title">欢迎来到小红书</h1>
            <p className="login-subtitle">标记我的生活</p>
          </div>

          <form className="login-form" onSubmit={handleSubmit}>
            <div className="form-group">
              <Input
                type="email"
                id="email"
                name="email"
                className={`form-input ${errors.email ? 'input-error' : ''}`}
                placeholder="请输入您的邮箱"
                value={formData.email}
                onChange={handleEmailChange}
                prefix={<MailOutlined />}
                size="large"
                title=""
                status={errors.email ? 'error' : ''}
              />
              {errors.email && (
                <div className="error-message">
                  {errors.email}
                </div>
              )}
            </div>

            <div className="form-group">
              <Input.Password
                id="password"
                name="password"
                className={`form-input ${errors.password ? 'input-error' : ''}`}
                placeholder="请输入您的密码"
                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-options">
              <Checkbox 
                checked={rememberMe}
                onChange={handleRememberMeChange}
              >
                记住我
              </Checkbox>
              <Link to="/forgot-password" className="forgot-password">忘记密码？</Link>
            </div>

            <button
              type="submit"
              className={`login-button ${isLoading ? 'loading' : ''}`}
              disabled={isLoading}
            >
              {isLoading ? (
                <>
                  <div className="loading-spinner"></div>
                  登录中...
                </>
              ) : (
                '登录'
              )}
            </button>
          </form>

          <div className="signup-link">
            <p>还没有账户？ <Link to="/register">立即注册</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 LoginPage;