/**
 * Email Verification Service
 * 邮箱验证码服务 - 统一入口
 */

const ImapConnector = require('./connectors/imap-connector');
const WindsurfParser = require('./parsers/windsurf-parser');
const emailConfig = require('./email-config');
const logger = require('../../../shared/logger');

class EmailVerificationService {
  constructor(config = null) {
    this.config = config || emailConfig.primary;
    this.connector = null;
    this.parsers = [
      new WindsurfParser()
      // 未来添加更多解析器
      // new GitHubParser(),
      // new TwitterParser(),
    ];
  }

  /**
   * 获取验证码
   * @param {string} siteName - 网站名称（如 'windsurf'）
   * @param {string} recipientEmail - 接收验证码的邮箱地址
   * @param {number} timeout - 超时时间（秒）
   * @returns {Promise<string>} - 验证码
   */
  async getVerificationCode(siteName, recipientEmail, timeout = 60) {
    logger.info('EmailVerification', `开始获取 ${siteName} 的验证码...`);
    logger.info('EmailVerification', `接收邮箱: ${recipientEmail}`);

    try {
      // 1. 初始化连接器
      this.connector = new ImapConnector(this.config);

      // 2. 等待验证码邮件
      const startTime = Date.now();
      const checkInterval = emailConfig.search.checkInterval * 1000; // 转换为毫秒
      let attempts = 0;

      while (Date.now() - startTime < timeout * 1000) {
        attempts++;
        logger.info('EmailVerification', `第 ${attempts} 次检查邮件...`);

        // 关键：每次都重新连接以获取最新邮件（QQ邮箱IMAP有延迟问题）
        if (attempts > 1) {
          logger.info('EmailVerification', '断开并重新连接以刷新邮件...');
          this.connector.disconnect();
          await this.sleep(1000);
        }
        
        await this.connector.connect();
        
        // 获取最新邮件（倒序排列）
        const emails = await this.connector.getLatestEmails(20, 1);

        if (emails && emails.length > 0) {
          logger.info('EmailVerification', `找到 ${emails.length} 封邮件`);
          
          // 打印最近5条邮件信息（倒序，最新的在前）
          const recentEmails = emails.slice(-5).reverse();
          logger.info('EmailVerification', '='.repeat(60));
          logger.info('EmailVerification', '最近5条邮件：');
          recentEmails.forEach((email, index) => {
            const dateStr = email.date ? new Date(email.date).toLocaleString('zh-CN') : 'N/A';
            logger.info('EmailVerification', `  ${index + 1}. 时间: ${dateStr}`);
            logger.info('EmailVerification', `     发件人: ${email.from}`);
            logger.info('EmailVerification', `     主题: ${email.subject}`);
            logger.info('EmailVerification', `     收件人: ${email.to}`);
          });
          logger.info('EmailVerification', '='.repeat(60));
          
          // 3. 查找匹配的邮件并提取验证码（从最新的开始）
          for (const email of emails.reverse()) {
            logger.info('EmailVerification', `检查邮件: 发件人="${email.from}", 主题="${email.subject}", 收件人="${email.to}"`);
            
            // 关键：检查收件人是否匹配
            const emailTo = (email.to || '').toLowerCase();
            const isForRecipient = emailTo.includes(recipientEmail.toLowerCase());
            
            if (!isForRecipient) {
              logger.info('EmailVerification', `  ✗ 跳过：收件人不匹配（需要：${recipientEmail}）`);
              continue;
            }
            
            logger.info('EmailVerification', `  ✓ 收件人匹配！`);
            
            for (const parser of this.parsers) {
              if (parser.canParse(email)) {
                logger.success('EmailVerification', `  ✓ 找到匹配的邮件: ${email.subject}`);
                
                const code = parser.extractCode(email);
                if (code) {
                  logger.success('EmailVerification', `  ✓ 成功提取验证码: ${code}`);
                  
                  // 标记为已读
                  try {
                    await this.connector.markAsRead(email.uid);
                  } catch (e) {
                    // 忽略标记失败
                  }

                  // 断开连接
                  this.connector.disconnect();
                  
                  return code;
                } else {
                  logger.warn('EmailVerification', `  邮件匹配但无法提取验证码`);
                }
              }
            }
          }
          logger.warn('EmailVerification', `未找到匹配的Windsurf验证码邮件`);
        } else {
          logger.info('EmailVerification', `没有邮件`);
        }

        // 等待一段时间后再检查
        logger.info('EmailVerification', `等待 ${emailConfig.search.checkInterval} 秒后重试...`);
        await this.sleep(checkInterval);
      }

      // 超时
      this.connector.disconnect();
      throw new Error(`获取验证码超时（${timeout}秒内未收到邮件）`);

    } catch (error) {
      if (this.connector) {
        this.connector.disconnect();
      }
      throw error;
    }
  }

  /**
   * 搜索特定主题的邮件并提取验证码
   * @param {string} subject - 邮件主题关键词
   * @param {number} timeout - 超时时间（秒）
   * @returns {Promise<string>}
   */
  async getCodeBySubject(subject, timeout = 60) {
    logger.info('EmailVerification', `搜索主题包含 "${subject}" 的邮件...`);

    try {
      this.connector = new ImapConnector(this.config);
      await this.connector.connect();

      const startTime = Date.now();
      const checkInterval = emailConfig.search.checkInterval * 1000;

      while (Date.now() - startTime < timeout * 1000) {
        const emails = await this.connector.searchBySubject(subject, 1);

        if (emails && emails.length > 0) {
          for (const email of emails.reverse()) {
            for (const parser of this.parsers) {
              if (parser.canParse(email)) {
                const code = parser.extractCode(email);
                if (code) {
                  logger.success('EmailVerification', `提取到验证码: ${code}`);
                  this.connector.disconnect();
                  return code;
                }
              }
            }
          }
        }

        await this.sleep(checkInterval);
      }

      this.connector.disconnect();
      throw new Error(`获取验证码超时`);

    } catch (error) {
      if (this.connector) {
        this.connector.disconnect();
      }
      throw error;
    }
  }

  /**
   * 添加新的解析器
   * @param {BaseParser} parser - 解析器实例
   */
  addParser(parser) {
    this.parsers.push(parser);
  }

  /**
   * 休眠
   * @param {number} ms - 毫秒
   */
  sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
  }
}

module.exports = EmailVerificationService;