src/auth/token_manager.js

import axios from 'axios';
import { log } from '../utils/logger.js';
import { generateSessionId, generateProjectId, generateTokenId, generateInstanceId } from '../utils/idGenerator.js';
import config, { getConfigJson } from '../config/config.js';
import { OAUTH_CONFIG } from '../constants/oauth.js';
import { buildAxiosRequestConfig } from '../utils/httpClient.js';
import {
  DEFAULT_REQUEST_COUNT_PER_TOKEN,
  TOKEN_REFRESH_BUFFER
} from '../constants/index.js';
import TokenStore from './token_store.js';
import { TokenError } from '../utils/errors.js';
import quotaManager from './quota_manager.js';
import tokenCooldownManager from './token_cooldown_manager.js';
import { randomUUID } from 'crypto';

// 轮询策略枚举
const RotationStrategy = {
  ROUND_ROBIN: 'round_robin',           // 均衡负载：每次请求切换
  QUOTA_EXHAUSTED: 'quota_exhausted',   // 额度耗尽才切换
  REQUEST_COUNT: 'request_count'        // 自定义次数后切换
};

/**
 * Token 管理器
 * 负责 Token 的存储、轮询、刷新等功能
 */
class TokenManager {
  /**
   * @param {string} filePath - Token 数据文件路径
   */
  constructor(filePath) {
    this.store = new TokenStore(filePath);
    /** @type {Array<Object>} */
    this.tokens = [];
    /** @type {number} */
    this.currentIndex = 0;

    // 轮询策略相关 - 使用原子操作避免锁
    /** @type {string} */
    this.rotationStrategy = RotationStrategy.ROUND_ROBIN;
    /** @type {number} */
    this.requestCountPerToken = DEFAULT_REQUEST_COUNT_PER_TOKEN;
    /** @type {Map<string, number>} */
    this.tokenRequestCounts = new Map();

    // 针对额度耗尽策略的可用 token 索引缓存（优化大规模账号场景）
    /** @type {number[]} */
    this.availableQuotaTokenIndices = [];
    /** @type {number} */
    this.currentQuotaIndex = 0;

    /** @type {Promise<void>|null} */
    this._initPromise = null;
  }

  async _initialize() {
    try {
      log.info('正在初始化token管理器...');
      const tokenArray = await this.store.readAll();

      this.tokens = tokenArray.filter(token => token.enable !== false).map(token => ({
        ...token,
        sessionId: generateSessionId(),
        instanceId: generateInstanceId(),
        deviceId: randomUUID(),
        sub: token?.sub ? token?.sub : "g1-pro-tier"
      }));

      this.currentIndex = 0;
      this.tokenRequestCounts.clear();
      this._rebuildAvailableQuotaTokens();

      // 加载轮询策略配置
      this.loadRotationConfig();

      if (this.tokens.length === 0) {
        log.warn('⚠ 暂无可用账号，请使用以下方式添加：');
        log.warn('  方式1: 运行 npm run login 命令登录');
        log.warn('  方式2: 访问前端管理页面添加账号');
      } else {
        log.info(`成功加载 ${this.tokens.length} 个可用token`);
        if (this.rotationStrategy === RotationStrategy.REQUEST_COUNT) {
          log.info(`轮询策略: ${this.rotationStrategy}, 每token请求 ${this.requestCountPerToken} 次后切换`);
        } else {
          log.info(`轮询策略: ${this.rotationStrategy}`);
        }

        // 并发刷新所有过期的 token
        await this._refreshExpiredTokensConcurrently();
      }
    } catch (error) {
      log.error('初始化token失败:', error.message);
      this.tokens = [];
    }
  }

  /**
   * 并发刷新所有过期的 token
   * @private
   */
  async _refreshExpiredTokensConcurrently() {
    const expiredTokens = this.tokens.filter(token => this.isExpired(token));
    if (expiredTokens.length === 0) {
      return;
    }

    // 获取 salt 用于生成 tokenId
    const salt = await this.store.getSalt();
    const tokenIds = expiredTokens.map(token => generateTokenId(token.refresh_token, salt));

    log.info(`正在批量刷新 ${tokenIds.length} 个token: ${tokenIds.join(', ')}`);
    const startTime = Date.now();

    const results = await Promise.allSettled(
      expiredTokens.map(token => this._refreshTokenSafe(token))
    );

    let successCount = 0;
    let failCount = 0;
    const tokensToDisable = [];
    const failedTokenIds = [];

    results.forEach((result, index) => {
      const token = expiredTokens[index];
      const tokenId = tokenIds[index];
      if (result.status === 'fulfilled') {
        if (result.value === 'success') {
          successCount++;
        } else if (result.value === 'disable') {
          tokensToDisable.push(token);
          failCount++;
          failedTokenIds.push(tokenId);
        }
      } else {
        failCount++;
        failedTokenIds.push(tokenId);
      }
    });

    // 批量禁用失效的 token
    for (const token of tokensToDisable) {
      this.disableToken(token);
    }

    const elapsed = Date.now() - startTime;
    if (failCount > 0) {
      log.warn(`刷新完成: 成功 ${successCount}, 失败 ${failCount} (${failedTokenIds.join(', ')}), 耗时 ${elapsed}ms`);
    } else {
      log.info(`刷新完成: 成功 ${successCount}, 耗时 ${elapsed}ms`);
    }
  }

  /**
   * 安全刷新单个 token（不抛出异常）
   * @param {Object} token - Token 对象
   * @returns {Promise<'success'|'disable'|'skip'>} 刷新结果
   * @private
   */
  async _refreshTokenSafe(token) {
    try {
      // 并发刷新时使用静默模式，避免重复打印日志
      await this.refreshToken(token, true);
      return 'success';
    } catch (error) {
      if (error.statusCode === 403 || error.statusCode === 400) {
        return 'disable';
      }
      throw error;
    }
  }

  async _ensureInitialized() {
    if (!this._initPromise) {
      this._initPromise = this._initialize();
    }
    return this._initPromise;
  }

  // 加载轮询策略配置
  loadRotationConfig() {
    try {
      const jsonConfig = getConfigJson();
      if (jsonConfig.rotation) {
        this.rotationStrategy = jsonConfig.rotation.strategy || RotationStrategy.ROUND_ROBIN;
        this.requestCountPerToken = jsonConfig.rotation.requestCount || 10;
      }
    } catch (error) {
      log.warn('加载轮询配置失败，使用默认值:', error.message);
    }
  }

  // 更新轮询策略（热更新）
  updateRotationConfig(strategy, requestCount) {
    if (strategy && Object.values(RotationStrategy).includes(strategy)) {
      this.rotationStrategy = strategy;
    }
    if (requestCount && requestCount > 0) {
      this.requestCountPerToken = requestCount;
    }
    // 重置计数器
    this.tokenRequestCounts.clear();
    if (this.rotationStrategy === RotationStrategy.REQUEST_COUNT) {
      log.info(`轮询策略已更新: ${this.rotationStrategy}, 每token请求 ${this.requestCountPerToken} 次后切换`);
    } else {
      log.info(`轮询策略已更新: ${this.rotationStrategy}`);
    }
  }

  // 重建额度耗尽策略下的可用 token 列表
  _rebuildAvailableQuotaTokens() {
    this.availableQuotaTokenIndices = [];
    this.tokens.forEach((token, index) => {
      if (token.enable !== false && token.hasQuota !== false) {
        this.availableQuotaTokenIndices.push(index);
      }
    });

    if (this.availableQuotaTokenIndices.length === 0) {
      this.currentQuotaIndex = 0;
    } else {
      this.currentQuotaIndex = this.currentQuotaIndex % this.availableQuotaTokenIndices.length;
    }
  }

  // 从额度耗尽策略的可用列表中移除指定下标
  _removeQuotaIndex(tokenIndex) {
    const pos = this.availableQuotaTokenIndices.indexOf(tokenIndex);
    if (pos !== -1) {
      this.availableQuotaTokenIndices.splice(pos, 1);
      if (this.currentQuotaIndex >= this.availableQuotaTokenIndices.length) {
        this.currentQuotaIndex = 0;
      }
    }
  }

  async fetchProjectId(token) {
    // 步骤1: 尝试 loadCodeAssist
    try {

      const {projectId,sub} = await this._tryLoadCodeAssist(token) || {};
      if (projectId) return {projectId,sub};
      log.warn('[fetchProjectId] loadCodeAssist 未返回 projectId，回退到 onboardUser');
    } catch (err) {
      log.warn(`[fetchProjectId] loadCodeAssist 失败: ${err.message}，回退到 onboardUser`);
    }

    // 步骤2: 回退到 onboardUser
    try {
      const {projectId,sub} = await this._tryOnboardUser(token) || {};
      if (projectId) return {projectId, sub};
      log.error('[fetchProjectId] loadCodeAssist 和 onboardUser 均未能获取 projectId');
      return {projectId: undefined, sub: "free-tier"};
    } catch (err) {
      log.error(`[fetchProjectId] onboardUser 失败: ${err.message}`);
      return {projectId: undefined, sub: "free-tier"};
    }
  }

  /**
   * 尝试通过 loadCodeAssist 获取 projectId
   * @param {Object} token - Token 对象
   * @returns {Promise<string|null>} projectId 或 null
   * @private
   */
  async _tryLoadCodeAssist(token) {
    const apiHost = config.api.host;
    const requestUrl = `https://${apiHost}/v1internal:loadCodeAssist`;
    const requestBody = {
      metadata: {
        ideType: 'ANTIGRAVITY',
        platform: 'PLATFORM_UNSPECIFIED',
        pluginType: 'GEMINI'
      }
    };

    log.info(`[loadCodeAssist] 请求: ${requestUrl}`);
    const response = await axios(buildAxiosRequestConfig({
      method: 'POST',
      url: requestUrl,
      headers: {
        'Host': apiHost,
        'User-Agent': config.api.userAgent,
        'Authorization': `Bearer ${token.access_token}`,
        'Content-Type': 'application/json',
        'Accept-Encoding': 'gzip'
      },
      data: JSON.stringify(requestBody)
    }));

    const data = response.data;
    // log.info(`[loadCodeAssist] 响应: ${JSON.stringify(data)}`); // 响应可能很大，不打印

    // 检查是否有 currentTier（表示用户已激活）
    let sub = "free-tier";
    if (data?.currentTier) {
      log.info('[loadCodeAssist] 用户已激活');
      const projectId = data.cloudaicompanionProject;
      if (projectId) {
        log.info(`[loadCodeAssist] 成功获取 projectId: ${projectId}`);
        sub = data.currentTier.id;
        return {projectId, sub};
      }
      log.warn('[loadCodeAssist] 响应中无 projectId');
      return null;
    }

    log.info('[loadCodeAssist] 用户未激活 (无 currentTier)');
    return null;
  }

  /**
   * 尝试通过 onboardUser 获取 projectId（长时间运行操作，需要轮询）
   * @param {Object} token - Token 对象
   * @returns {Promise<string|null>} projectId 或 null
   * @private
   */
  async _tryOnboardUser(token) {
    const apiHost = config.api.host;
    const requestUrl = `https://${apiHost}/v1internal:onboardUser`;

    // 首先获取用户的 tier 信息
    const tierId = await this._getOnboardTier(token);
    if (!tierId) {
      log.error('[onboardUser] 无法确定用户 tier');
      return null;
    }

    log.info(`[onboardUser] 用户 tier: ${tierId}`);

    const requestBody = {
      tierId: tierId,
      metadata: {
        ideType: 'ANTIGRAVITY',
        platform: 'PLATFORM_UNSPECIFIED',
        pluginType: 'GEMINI'
      }
    };

    log.info(`[onboardUser] 请求: ${requestUrl}`);

    // onboardUser 是长时间运行操作，需要轮询
    const maxAttempts = 5;
    for (let attempt = 1; attempt <= maxAttempts; attempt++) {
      log.info(`[onboardUser] 轮询尝试 ${attempt}/${maxAttempts}`);

      const response = await axios(buildAxiosRequestConfig({
        method: 'POST',
        url: requestUrl,
        headers: {
          'Host': apiHost,
          'User-Agent': config.api.userAgent,
          'Authorization': `Bearer ${token.access_token}`,
          'Content-Type': 'application/json',
          'Accept-Encoding': 'gzip'
        },
        data: JSON.stringify(requestBody),
        timeout: 30000
      }));

      const data = response.data;
      // log.info(`[onboardUser] 响应: ${JSON.stringify(data)}`); // 响应可能很大，不打印

      // 检查长时间运行操作是否完成
      let sub = "g1-pro-tier";
      if (data?.done) {
        log.info('[onboardUser] 操作完成');
        const responseData = data.response || {};
        const projectObj = responseData.cloudaicompanionProject;

        let projectId = null;
        if (typeof projectObj === 'object' && projectObj !== null) {
          projectId = projectObj.id;
        } else if (typeof projectObj === 'string') {
          projectId = projectObj;
        }

        if (projectId) {
          log.info(`[onboardUser] 成功获取 projectId: ${projectId}`);
          return {projectId,sub};
        }
        log.warn('[onboardUser] 操作完成但响应中无 projectId');
        return null;
      }

      log.info('[onboardUser] 操作进行中，等待 2 秒...');
      await new Promise(resolve => setTimeout(resolve, 2000));
    }

    log.error('[onboardUser] 超时：操作未在 10 秒内完成');
    return null;
  }

  /**
   * 从 loadCodeAssist 响应中获取用户应该注册的 tier
   * @param {Object} token - Token 对象
   * @returns {Promise<string|null>} tier_id 或 null
   * @private
   */
  async _getOnboardTier(token) {
    const apiHost = config.api.host;
    const requestUrl = `https://${apiHost}/v1internal:loadCodeAssist`;
    const requestBody = {
      metadata: {
        ideType: 'ANTIGRAVITY',
        platform: 'PLATFORM_UNSPECIFIED',
        pluginType: 'GEMINI'
      }
    };

    log.info(`[_getOnboardTier] 请求: ${requestUrl}`);

    try {
      const response = await axios(buildAxiosRequestConfig({
        method: 'POST',
        url: requestUrl,
        headers: {
          'Host': apiHost,
          'User-Agent': config.api.userAgent,
          'Authorization': `Bearer ${token.access_token}`,
          'Content-Type': 'application/json',
          'Accept-Encoding': 'gzip'
        },
        data: JSON.stringify(requestBody),
        timeout: 30000
      }));

      const data = response.data;
      // log.info(`[_getOnboardTier] 响应: ${JSON.stringify(data)}`); // 响应可能很大，不打印

      // 查找默认的 tier
      const allowedTiers = data?.allowedTiers || [];
      for (const tier of allowedTiers) {
        if (tier.isDefault) {
          log.info(`[_getOnboardTier] 找到默认 tier: ${tier.id}`);
          return tier.id;
        }
      }

      // 如果没有默认 tier，使用 LEGACY 作为回退
      log.warn('[_getOnboardTier] 未找到默认 tier，使用 LEGACY');
      return 'LEGACY';
    } catch (err) {
      log.error(`[_getOnboardTier] 获取 tier 失败: ${err.message}`);
      return null;
    }
  }

  /**
   * 根据 tokenId 获取并更新 projectId
   * @param {string} tokenId - 安全的 token ID
   * @returns {Promise<Object>} 包含 projectId 的结果
   */
  async fetchProjectIdForToken(tokenId) {
    const tokenData = await this.findTokenById(tokenId);
    if (!tokenData) {
      throw new TokenError('Token不存在', null, 404);
    }

    // 确保 token 未过期
    if (this.isExpired(tokenData)) {
      await this.refreshToken(tokenData);
    }

    const {projectId,sub} = await this.fetchProjectId(tokenData) || {};
    if (!projectId) {
      throw new TokenError('无法获取 projectId，该账号可能无资格', null, 400);
    }

    // 更新并保存
    tokenData.projectId = projectId;
    tokenData.sub = sub;
    tokenData.hasQuota = true;
    this.saveToFile(tokenData);

    // 同步更新内存中的 token
    const memoryToken = this.tokens.find(t => t.refresh_token === tokenData.refresh_token);
    if (memoryToken) {
      memoryToken.projectId = projectId;
      memoryToken.sub = sub;
      memoryToken.hasQuota = true;
    }

    return { projectId };
  }

  /**
   * 检查 Token 是否过期
   * @param {Object} token - Token 对象
   * @returns {boolean} 是否过期
   */
  isExpired(token) {
    if (!token.timestamp || !token.expires_in) return true;
    const expiresAt = token.timestamp + (token.expires_in * 1000);
    return Date.now() >= expiresAt - TOKEN_REFRESH_BUFFER;
  }

  async refreshToken(token, silent = false) {
    // 获取 tokenId 用于日志显示
    const salt = await this.store.getSalt();
    const tokenId = generateTokenId(token.refresh_token, salt);
    if (!silent) {
      log.info(`正在刷新token: ${tokenId}`);
    }

    const body = new URLSearchParams({
      client_id: OAUTH_CONFIG.CLIENT_ID,
      client_secret: OAUTH_CONFIG.CLIENT_SECRET,
      grant_type: 'refresh_token',
      refresh_token: token.refresh_token
    });

    try {
      const response = await axios(buildAxiosRequestConfig({
        method: 'POST',
        url: OAUTH_CONFIG.TOKEN_URL,
        headers: {
          'Host': 'oauth2.googleapis.com',
          'User-Agent': 'Go-http-client/1.1',
          'Content-Type': 'application/x-www-form-urlencoded',
          'Accept-Encoding': 'gzip'
        },
        data: body.toString()
      }));

      token.access_token = response.data.access_token;
      token.expires_in = response.data.expires_in;
      token.timestamp = Date.now();
      this.saveToFile(token);
      return token;
    } catch (error) {
      const statusCode = error.response?.status;
      const rawBody = error.response?.data;
      const message = typeof rawBody === 'string' ? rawBody : (rawBody?.error?.message || error.message || '刷新 token 失败');
      throw new TokenError(message, tokenId, statusCode || 500);
    }
  }

  saveToFile(tokenToUpdate = null) {
    // 保持与旧接口同步调用方式一致，内部使用异步写入
    this.store.mergeActiveTokens(this.tokens, tokenToUpdate).catch((error) => {
      log.error('保存账号配置文件失败:', error.message);
    });
  }

  disableToken(token) {
    log.warn(`禁用token ...${token.access_token.slice(-8)}`)
    token.enable = false;
    this.saveToFile();
    // 清理该 token 的请求计数（避免内存泄漏）
    this.tokenRequestCounts.delete(token.refresh_token);
    this.tokens = this.tokens.filter(t => t.refresh_token !== token.refresh_token);
    this.currentIndex = this.currentIndex % Math.max(this.tokens.length, 1);
    // tokens 结构发生变化时，重建额度耗尽策略下的可用列表
    this._rebuildAvailableQuotaTokens();
  }

  // 原子操作：获取并递增请求计数
  incrementRequestCount(tokenKey) {
    const current = this.tokenRequestCounts.get(tokenKey) || 0;
    const newCount = current + 1;
    this.tokenRequestCounts.set(tokenKey, newCount);
    return newCount;
  }

  // 原子操作：重置请求计数
  resetRequestCount(tokenKey) {
    this.tokenRequestCounts.set(tokenKey, 0);
  }


  // 标记token额度耗尽
  markQuotaExhausted(token) {
    token.hasQuota = false;
    this.saveToFile(token);
    log.warn(`...${token.access_token.slice(-8)}: 额度已耗尽，标记为无额度`);

    if (this.rotationStrategy === RotationStrategy.QUOTA_EXHAUSTED) {
      const tokenIndex = this.tokens.findIndex(t => t.refresh_token === token.refresh_token);
      if (tokenIndex !== -1) {
        this._removeQuotaIndex(tokenIndex);
      }
      this.currentIndex = (this.currentIndex + 1) % Math.max(this.tokens.length, 1);
    }
  }

  // 恢复token额度（用于额度重置后）
  restoreQuota(token) {
    token.hasQuota = true;
    this.saveToFile(token);
    log.info(`...${token.access_token.slice(-8)}: 额度已恢复`);
  }

  /**
   * 记录一次请求（用于额度预估）
   * @param {Object} token - Token 对象
   * @param {string} modelId - 使用的模型 ID
   */
  async recordRequest(token, modelId) {
    if (!token || !modelId) return;

    try {
      const salt = await this.store.getSalt();
      const tokenId = generateTokenId(token.refresh_token, salt);
      quotaManager.recordRequest(tokenId, modelId);
    } catch (error) {
      // 记录失败不影响请求
      log.warn('记录请求次数失败:', error.message);
    }
  }

  /**
   * 准备单个 token（刷新 + 获取 projectId）
   * @param {Object} token - Token 对象
   * @returns {Promise<'ready'|'skip'|'disable'>} 处理结果
   * @private
   */
  async _prepareToken(token) {
    // 刷新过期 token
    if (this.isExpired(token)) {
      await this.refreshToken(token);
    }

    // 获取 projectId
    if (!token.projectId) {
      if (config.skipProjectIdFetch) {
        token.projectId = generateProjectId();
        this.saveToFile(token);
        log.info(`...${token.access_token.slice(-8)}: 使用随机生成的projectId: ${token.projectId}`);
      } else {
        const {projectId,sub} = await this.fetchProjectId(token) || {};
        if (projectId === undefined) {
          log.warn(`...${token.access_token.slice(-8)}: 无资格获取projectId，禁用账号`);
          return 'disable';
        }
        token.projectId = projectId;
        token.sub = sub;
        this.saveToFile(token);
      }
    }

    return 'ready';
  }

  /**
   * 处理 token 准备过程中的错误
   * @param {Error} error - 错误对象
   * @param {Object} token - Token 对象
   * @returns {'disable'|'skip'} 处理结果
   * @private
   */
  _handleTokenError(error, token) {
    const suffix = token.access_token?.slice(-8) || 'unknown';
    if (error.statusCode === 403 || error.statusCode === 400) {
      log.warn(`...${suffix}: Token 已失效或错误，已自动禁用该账号`);
      return 'disable';
    }
    log.error(`...${suffix} 操作失败:`, error.message);
    return 'skip';
  }

  /**
   * 重置所有 token 的额度状态
   * @private
   */
  _resetAllQuotas() {
    log.warn('所有token额度已耗尽，重置额度状态');
    this.tokens.forEach(t => {
      t.hasQuota = true;
    });
    this.saveToFile();
    this._rebuildAvailableQuotaTokens();
  }

  /**
   * 检查所有 token 对指定模型是否都不可用（额度为0或在冷却中）
   * @param {string} modelId - 模型 ID
   * @returns {boolean} true = 所有 token 对该模型都不可用
   * @private
   */
  _checkAllTokensExhaustedForModel(modelId) {
    if (!modelId || this.tokens.length === 0) return false;

    for (const token of this.tokens) {
      if (this._canUseTokenForModel(token, modelId)) {
        return false; // 有至少一个 token 可用
      }
    }
    return true; // 所有 token 都不可用
  }

  /**
   * 检查 token 对指定模型是否有额度
   * @param {Object} token - Token 对象
   * @param {string} modelId - 模型 ID
   * @returns {boolean} true = 有额度或无数据，false = 额度为 0
   * @private
   */
  _hasQuotaForModel(token, modelId) {
    if (!token || !modelId) return true;

    try {
      const salt = this.store._salt; // 使用同步方式获取 salt
      if (!salt) return true; // 没有 salt，假设有额度

      const tokenId = generateTokenId(token.refresh_token, salt);
      return quotaManager.hasQuotaForModel(tokenId, modelId);
    } catch (error) {
      // 出错时假设有额度
      return true;
    }
  }

  /**
   * 检查 token 对指定模型是否在冷却中
   * @param {Object} token - Token 对象
   * @param {string} modelId - 模型 ID
   * @returns {boolean} true = 可用（不在冷却中），false = 在冷却中
   * @private
   */
  _isTokenAvailableForModel(token, modelId) {
    if (!token || !modelId) return true;

    try {
      const salt = this.store._salt;
      if (!salt) return true;

      const tokenId = generateTokenId(token.refresh_token, salt);
      return tokenCooldownManager.isAvailable(tokenId, modelId);
    } catch (error) {
      return true;
    }
  }

  /**
   * 检查 token 对指定模型是否可用（既有额度，又不在冷却中）
   * @param {Object} token - Token 对象
   * @param {string} modelId - 模型 ID
   * @returns {boolean} true = 可用，false = 不可用
   * @private
   */
  _canUseTokenForModel(token, modelId) {
    if (!token || !modelId) return true;

    // 先检查冷却状态（更严格的限制）
    if (!this._isTokenAvailableForModel(token, modelId)) {
      return false;
    }

    // 再检查额度
    return this._hasQuotaForModel(token, modelId);
  }

  /**
   * 获取可用的 token
   * @param {string} [modelId] - 可选，请求的模型 ID，用于检查该模型的额度
   * @returns {Promise<Object|null>} token 对象
   */
  async getToken(modelId = null) {
    await this._ensureInitialized();
    if (this.tokens.length === 0) return null;

    // 针对额度耗尽策略做单独的高性能处理
    if (this.rotationStrategy === RotationStrategy.QUOTA_EXHAUSTED) {
      return this._getTokenForQuotaExhaustedStrategy(modelId);
    }

    return this._getTokenForDefaultStrategy(modelId);
  }

  /**
   * 额度耗尽策略的 token 获取
   * @param {string} [modelId] - 请求的模型 ID
   * @private
   */
  async _getTokenForQuotaExhaustedStrategy(modelId = null) {
    // 如果当前没有可用 token，尝试重置额度
    if (this.availableQuotaTokenIndices.length === 0) {
      this._resetAllQuotas();
    }

    const totalAvailable = this.availableQuotaTokenIndices.length;
    if (totalAvailable === 0) {
      return null;
    }

    // 如果提供了 modelId，先检查是否所有 token 对该模型的额度都为 0
    let allTokensExhausted = false;
    if (modelId) {
      allTokensExhausted = this._checkAllTokensExhaustedForModel(modelId);
    }

    const startIndex = this.currentQuotaIndex % totalAvailable;

    for (let i = 0; i < totalAvailable; i++) {
      const listIndex = (startIndex + i) % totalAvailable;
      const tokenIndex = this.availableQuotaTokenIndices[listIndex];
      const token = this.tokens[tokenIndex];

      // 如果提供了 modelId 且不是所有 token 都耗尽，检查该 token 对该模型是否可用
      if (modelId && !allTokensExhausted) {
        if (!this._canUseTokenForModel(token, modelId)) {
          // 该 token 对该模型不可用（额度为 0 或在冷却中），跳过
          continue;
        }
      }

      try {
        const result = await this._prepareToken(token);
        if (result === 'disable') {
          this.disableToken(token);
          this._rebuildAvailableQuotaTokens();
          if (this.tokens.length === 0 || this.availableQuotaTokenIndices.length === 0) {
            return null;
          }
          continue;
        }

        this.currentIndex = tokenIndex;
        this.currentQuotaIndex = listIndex;
        return token;
      } catch (error) {
        const action = this._handleTokenError(error, token);
        if (action === 'disable') {
          this.disableToken(token);
          this._rebuildAvailableQuotaTokens();
          if (this.tokens.length === 0 || this.availableQuotaTokenIndices.length === 0) {
            return null;
          }
        }
        // skip: 继续尝试下一个 token
      }
    }

    // 所有可用 token 都不可用，重置额度状态
    this._resetAllQuotas();
    return this.tokens[0] || null;
  }

  /**
   * 默认策略（round_robin / request_count）的 token 获取
   * @param {string} [modelId] - 请求的模型 ID
   * @private
   */
  async _getTokenForDefaultStrategy(modelId = null) {
    const totalTokens = this.tokens.length;
    const startIndex = this.currentIndex;

    // 如果提供了 modelId，先检查是否所有 token 对该模型的额度都为 0
    let allTokensExhausted = false;
    if (modelId) {
      allTokensExhausted = this._checkAllTokensExhaustedForModel(modelId);
    }

    for (let i = 0; i < totalTokens; i++) {
      const index = (startIndex + i) % totalTokens;
      const token = this.tokens[index];

      // 如果提供了 modelId 且不是所有 token 都耗尽，检查该 token 对该模型是否可用
      if (modelId && !allTokensExhausted) {
        if (!this._canUseTokenForModel(token, modelId)) {
          // 该 token 对该模型不可用（额度为 0 或在冷却中），跳过
          continue;
        }
      }

      try {
        const result = await this._prepareToken(token);
        if (result === 'disable') {
          this.disableToken(token);
          if (this.tokens.length === 0) return null;
          continue;
        }

        // 更新当前索引
        this.currentIndex = index;

        // 根据策略决定是否切换（仅 round_robin 策略每次切换）
        if (this.rotationStrategy === RotationStrategy.ROUND_ROBIN) {
          this.currentIndex = (this.currentIndex + 1) % this.tokens.length;
        } else if (this.rotationStrategy === RotationStrategy.REQUEST_COUNT) {
          // 自定义次数策略：请求计数在 recordRequest 中处理，这里只处理切换逻辑
          const tokenKey = token.refresh_token;
          const count = this.tokenRequestCounts.get(tokenKey) || 0;
          if (count >= this.requestCountPerToken) {
            this.resetRequestCount(tokenKey);
            this.currentIndex = (this.currentIndex + 1) % this.tokens.length;
          }
        }

        return token;
      } catch (error) {
        const action = this._handleTokenError(error, token);
        if (action === 'disable') {
          this.disableToken(token);
          if (this.tokens.length === 0) return null;
        }
        // skip: 继续尝试下一个 token
      }
    }

    return null;
  }

  disableCurrentToken(token) {
    const found = this.tokens.find(t => t.access_token === token.access_token);
    if (found) {
      this.disableToken(found);
    }
  }

  // API管理方法
  async reload() {
    this._initPromise = this._initialize();
    await this._initPromise;
    log.info('Token已热重载');
  }

  async addToken(tokenData) {
    try {
      const allTokens = await this.store.readAll();

      const newToken = {
        access_token: tokenData.access_token,
        refresh_token: tokenData.refresh_token,
        expires_in: tokenData.expires_in || 3599,
        timestamp: tokenData.timestamp || Date.now(),
        enable: tokenData.enable !== undefined ? tokenData.enable : true
      };

      if (tokenData.projectId) {
        newToken.projectId = tokenData.projectId;
      }
      if (tokenData.email) {
        newToken.email = tokenData.email;
      }
      if (tokenData.hasQuota !== undefined) {
        newToken.hasQuota = tokenData.hasQuota;
      }
      if (tokenData.sub) {
        newToken.sub = tokenData.sub;
      }

      allTokens.push(newToken);
      await this.store.writeAll(allTokens);

      await this.reload();
      return { success: true, message: 'Token添加成功' };
    } catch (error) {
      log.error('添加Token失败:', error.message);
      return { success: false, message: error.message };
    }
  }

  async updateToken(refreshToken, updates) {
    try {
      const allTokens = await this.store.readAll();

      const index = allTokens.findIndex(t => t.refresh_token === refreshToken);
      if (index === -1) {
        return { success: false, message: 'Token不存在' };
      }

      allTokens[index] = { ...allTokens[index], ...updates };
      await this.store.writeAll(allTokens);

      await this.reload();
      return { success: true, message: 'Token更新成功' };
    } catch (error) {
      log.error('更新Token失败:', error.message);
      return { success: false, message: error.message };
    }
  }

  async deleteToken(refreshToken) {
    try {
      const allTokens = await this.store.readAll();

      const filteredTokens = allTokens.filter(t => t.refresh_token !== refreshToken);
      if (filteredTokens.length === allTokens.length) {
        return { success: false, message: 'Token不存在' };
      }

      await this.store.writeAll(filteredTokens);

      await this.reload();
      return { success: true, message: 'Token删除成功' };
    } catch (error) {
      log.error('删除Token失败:', error.message);
      return { success: false, message: error.message };
    }
  }

  async getTokenList() {
    try {
      const allTokens = await this.store.readAll();
      const salt = await this.store.getSalt();

      return allTokens.map(token => ({
        // 使用安全的 tokenId 替代完整的 refresh_token
        id: generateTokenId(token.refresh_token, salt),
        expires_in: token.expires_in,
        timestamp: token.timestamp,
        enable: token.enable !== false,
        projectId: token.projectId || null,
        email: token.email || null,
        hasQuota: token.hasQuota !== false
      }));
    } catch (error) {
      log.error('获取Token列表失败:', error.message);
      return [];
    }
  }

  /**
   * 根据 tokenId 查找完整的 token 对象
   * @param {string} tokenId - 安全的 token ID
   * @returns {Promise<Object|null>} token 对象或 null
   */
  async findTokenById(tokenId) {
    try {
      const allTokens = await this.store.readAll();
      const salt = await this.store.getSalt();

      return allTokens.find(token =>
        generateTokenId(token.refresh_token, salt) === tokenId
      ) || null;
    } catch (error) {
      log.error('查找Token失败:', error.message);
      return null;
    }
  }

  /**
   * 根据 tokenId 更新 token
   * @param {string} tokenId - 安全的 token ID
   * @param {Object} updates - 更新内容
   * @returns {Promise<Object>} 操作结果
   */
  async updateTokenById(tokenId, updates) {
    try {
      const allTokens = await this.store.readAll();
      const salt = await this.store.getSalt();

      const index = allTokens.findIndex(token =>
        generateTokenId(token.refresh_token, salt) === tokenId
      );

      if (index === -1) {
        return { success: false, message: 'Token不存在' };
      }

      allTokens[index] = { ...allTokens[index], ...updates };
      await this.store.writeAll(allTokens);

      await this.reload();
      return { success: true, message: 'Token更新成功' };
    } catch (error) {
      log.error('更新Token失败:', error.message);
      return { success: false, message: error.message };
    }
  }

  /**
   * 根据 tokenId 删除 token
   * @param {string} tokenId - 安全的 token ID
   * @returns {Promise<Object>} 操作结果
   */
  async deleteTokenById(tokenId) {
    try {
      const allTokens = await this.store.readAll();
      const salt = await this.store.getSalt();

      const filteredTokens = allTokens.filter(token =>
        generateTokenId(token.refresh_token, salt) !== tokenId
      );

      if (filteredTokens.length === allTokens.length) {
        return { success: false, message: 'Token不存在' };
      }

      await this.store.writeAll(filteredTokens);

      await this.reload();
      return { success: true, message: 'Token删除成功' };
    } catch (error) {
      log.error('删除Token失败:', error.message);
      return { success: false, message: error.message };
    }
  }

  /**
   * 根据 tokenId 刷新 token
   * @param {string} tokenId - 安全的 token ID
   * @returns {Promise<Object>} 刷新后的 token 信息（不含敏感数据）
   */
  async refreshTokenById(tokenId) {
    const tokenData = await this.findTokenById(tokenId);
    if (!tokenData) {
      throw new TokenError('Token不存在', null, 404);
    }

    const refreshedToken = await this.refreshToken(tokenData);
    return {
      expires_in: refreshedToken.expires_in,
      timestamp: refreshedToken.timestamp
    };
  }

  /**
   * 获取盐值（用于前端验证等场景）
   * @returns {Promise<string>} 盐值
   */
  async getSalt() {
    return this.store.getSalt();
  }

  /**
   * 根据 token 对象获取 tokenId
   * @param {Object} token - Token 对象
   * @returns {Promise<string|null>} tokenId，如果无法生成返回 null
   */
  async getTokenId(token) {
    if (!token?.refresh_token) return null;
    try {
      const salt = await this.store.getSalt();
      if (!salt) return null;
      return generateTokenId(token.refresh_token, salt);
    } catch (error) {
      log.error(`生成tokenId失败: ${error.message}`);
      return null;
    }
  }

  // 获取当前轮询配置
  getRotationConfig() {
    return {
      strategy: this.rotationStrategy,
      requestCount: this.requestCountPerToken,
      currentIndex: this.currentIndex,
      tokenCounts: Object.fromEntries(this.tokenRequestCounts)
    };
  }
}

// 导出策略枚举
export { RotationStrategy };

const tokenManager = new TokenManager();
export default tokenManager;