const geminiAccountService = require('./geminiAccountService');
const accountGroupService = require('./accountGroupService');
const redis = require('../models/redis');
const logger = require('../utils/logger');

class UnifiedGeminiScheduler {
  constructor() {
    this.SESSION_MAPPING_PREFIX = 'unified_gemini_session_mapping:';
  }

  // 🔧 辅助方法：检查账户是否可调度（兼容字符串和布尔值）
  _isSchedulable(schedulable) {
    // 如果是 undefined 或 null，默认为可调度
    if (schedulable === undefined || schedulable === null) {
      return true;
    }
    // 明确设置为 false（布尔值）或 'false'（字符串）时不可调度
    return schedulable !== false && schedulable !== 'false';
  }

  // 🎯 统一调度Gemini账号
  async selectAccountForApiKey(apiKeyData, sessionHash = null, requestedModel = null) {
    try {
      // 如果API Key绑定了专属账户或分组，优先使用
      if (apiKeyData.geminiAccountId) {
        // 检查是否是分组
        if (apiKeyData.geminiAccountId.startsWith('group:')) {
          const groupId = apiKeyData.geminiAccountId.replace('group:', '');
          logger.info(`🎯 API key ${apiKeyData.name} is bound to group ${groupId}, selecting from group`);
          return await this.selectAccountFromGroup(groupId, sessionHash, requestedModel, apiKeyData);
        }
        
        // 普通专属账户
        const boundAccount = await geminiAccountService.getAccount(apiKeyData.geminiAccountId);
        if (boundAccount && boundAccount.isActive === 'true' && boundAccount.status !== 'error') {
          logger.info(`🎯 Using bound dedicated Gemini account: ${boundAccount.name} (${apiKeyData.geminiAccountId}) for API key ${apiKeyData.name}`);
          return {
            accountId: apiKeyData.geminiAccountId,
            accountType: 'gemini'
          };
        } else {
          logger.warn(`⚠️ Bound Gemini account ${apiKeyData.geminiAccountId} is not available, falling back to pool`);
        }
      }

      // 如果有会话哈希，检查是否有已映射的账户
      if (sessionHash) {
        const mappedAccount = await this._getSessionMapping(sessionHash);
        if (mappedAccount) {
          // 验证映射的账户是否仍然可用
          const isAvailable = await this._isAccountAvailable(mappedAccount.accountId, mappedAccount.accountType);
          if (isAvailable) {
            logger.info(`🎯 Using sticky session account: ${mappedAccount.accountId} (${mappedAccount.accountType}) for session ${sessionHash}`);
            return mappedAccount;
          } else {
            logger.warn(`⚠️ Mapped account ${mappedAccount.accountId} is no longer available, selecting new account`);
            await this._deleteSessionMapping(sessionHash);
          }
        }
      }

      // 获取所有可用账户
      const availableAccounts = await this._getAllAvailableAccounts(apiKeyData, requestedModel);
      
      if (availableAccounts.length === 0) {
        // 提供更详细的错误信息
        if (requestedModel) {
          throw new Error(`No available Gemini accounts support the requested model: ${requestedModel}`);
        } else {
          throw new Error('No available Gemini accounts');
        }
      }

      // 按优先级和最后使用时间排序
      const sortedAccounts = this._sortAccountsByPriority(availableAccounts);

      // 选择第一个账户
      const selectedAccount = sortedAccounts[0];
      
      // 如果有会话哈希，建立新的映射
      if (sessionHash) {
        await this._setSessionMapping(sessionHash, selectedAccount.accountId, selectedAccount.accountType);
        logger.info(`🎯 Created new sticky session mapping: ${selectedAccount.name} (${selectedAccount.accountId}, ${selectedAccount.accountType}) for session ${sessionHash}`);
      }

      logger.info(`🎯 Selected account: ${selectedAccount.name} (${selectedAccount.accountId}, ${selectedAccount.accountType}) with priority ${selectedAccount.priority} for API key ${apiKeyData.name}`);
      
      return {
        accountId: selectedAccount.accountId,
        accountType: selectedAccount.accountType
      };
    } catch (error) {
      logger.error('❌ Failed to select account for API key:', error);
      throw error;
    }
  }

  // 📋 获取所有可用账户
  async _getAllAvailableAccounts(apiKeyData, requestedModel = null) {
    const availableAccounts = [];

    // 如果API Key绑定了专属账户，优先返回
    if (apiKeyData.geminiAccountId) {
      const boundAccount = await geminiAccountService.getAccount(apiKeyData.geminiAccountId);
      if (boundAccount && boundAccount.isActive === 'true' && boundAccount.status !== 'error') {
        const isRateLimited = await this.isAccountRateLimited(boundAccount.id);
        if (!isRateLimited) {
          // 检查模型支持
          if (requestedModel && boundAccount.supportedModels && boundAccount.supportedModels.length > 0) {
            // 处理可能带有 models/ 前缀的模型名
            const normalizedModel = requestedModel.replace('models/', '');
            const modelSupported = boundAccount.supportedModels.some(model => 
              model.replace('models/', '') === normalizedModel
            );
            if (!modelSupported) {
              logger.warn(`⚠️ Bound Gemini account ${boundAccount.name} does not support model ${requestedModel}`);
              return availableAccounts;
            }
          }
          
          logger.info(`🎯 Using bound dedicated Gemini account: ${boundAccount.name} (${apiKeyData.geminiAccountId})`);
          return [{
            ...boundAccount,
            accountId: boundAccount.id,
            accountType: 'gemini',
            priority: parseInt(boundAccount.priority) || 50,
            lastUsedAt: boundAccount.lastUsedAt || '0'
          }];
        }
      } else {
        logger.warn(`⚠️ Bound Gemini account ${apiKeyData.geminiAccountId} is not available`);
      }
    }

    // 获取所有Gemini账户（共享池）
    const geminiAccounts = await geminiAccountService.getAllAccounts();
    for (const account of geminiAccounts) {
      if (account.isActive === 'true' && 
          account.status !== 'error' &&
          (account.accountType === 'shared' || !account.accountType) && // 兼容旧数据
          this._isSchedulable(account.schedulable)) { // 检查是否可调度
        
        // 检查token是否过期
        const isExpired = geminiAccountService.isTokenExpired(account);
        if (isExpired && !account.refreshToken) {
          logger.warn(`⚠️ Gemini account ${account.name} token expired and no refresh token available`);
          continue;
        }
        
        // 检查模型支持
        if (requestedModel && account.supportedModels && account.supportedModels.length > 0) {
          // 处理可能带有 models/ 前缀的模型名
          const normalizedModel = requestedModel.replace('models/', '');
          const modelSupported = account.supportedModels.some(model => 
            model.replace('models/', '') === normalizedModel
          );
          if (!modelSupported) {
            logger.debug(`⏭️ Skipping Gemini account ${account.name} - doesn't support model ${requestedModel}`);
            continue;
          }
        }
        
        // 检查是否被限流
        const isRateLimited = await this.isAccountRateLimited(account.id);
        if (!isRateLimited) {
          availableAccounts.push({
            ...account,
            accountId: account.id,
            accountType: 'gemini',
            priority: parseInt(account.priority) || 50, // 默认优先级50
            lastUsedAt: account.lastUsedAt || '0'
          });
        }
      }
    }
    
    logger.info(`📊 Total available Gemini accounts: ${availableAccounts.length}`);
    return availableAccounts;
  }

  // 🔢 按优先级和最后使用时间排序账户
  _sortAccountsByPriority(accounts) {
    return accounts.sort((a, b) => {
      // 首先按优先级排序（数字越小优先级越高）
      if (a.priority !== b.priority) {
        return a.priority - b.priority;
      }
      
      // 优先级相同时，按最后使用时间排序（最久未使用的优先）
      const aLastUsed = new Date(a.lastUsedAt || 0).getTime();
      const bLastUsed = new Date(b.lastUsedAt || 0).getTime();
      return aLastUsed - bLastUsed;
    });
  }

  // 🔍 检查账户是否可用
  async _isAccountAvailable(accountId, accountType) {
    try {
      if (accountType === 'gemini') {
        const account = await geminiAccountService.getAccount(accountId);
        if (!account || account.isActive !== 'true' || account.status === 'error') {
          return false;
        }
        // 检查是否可调度
        if (!this._isSchedulable(account.schedulable)) {
          logger.info(`🚫 Gemini account ${accountId} is not schedulable`);
          return false;
        }
        return !(await this.isAccountRateLimited(accountId));
      }
      return false;
    } catch (error) {
      logger.warn(`⚠️ Failed to check account availability: ${accountId}`, error);
      return false;
    }
  }

  // 🔗 获取会话映射
  async _getSessionMapping(sessionHash) {
    const client = redis.getClientSafe();
    const mappingData = await client.get(`${this.SESSION_MAPPING_PREFIX}${sessionHash}`);
    
    if (mappingData) {
      try {
        return JSON.parse(mappingData);
      } catch (error) {
        logger.warn('⚠️ Failed to parse session mapping:', error);
        return null;
      }
    }
    
    return null;
  }

  // 💾 设置会话映射
  async _setSessionMapping(sessionHash, accountId, accountType) {
    const client = redis.getClientSafe();
    const mappingData = JSON.stringify({ accountId, accountType });
    
    // 设置1小时过期
    await client.setex(
      `${this.SESSION_MAPPING_PREFIX}${sessionHash}`,
      3600,
      mappingData
    );
  }

  // 🗑️ 删除会话映射
  async _deleteSessionMapping(sessionHash) {
    const client = redis.getClientSafe();
    await client.del(`${this.SESSION_MAPPING_PREFIX}${sessionHash}`);
  }

  // 🚫 标记账户为限流状态
  async markAccountRateLimited(accountId, accountType, sessionHash = null) {
    try {
      if (accountType === 'gemini') {
        await geminiAccountService.setAccountRateLimited(accountId, true);
      }

      // 删除会话映射
      if (sessionHash) {
        await this._deleteSessionMapping(sessionHash);
      }

      return { success: true };
    } catch (error) {
      logger.error(`❌ Failed to mark account as rate limited: ${accountId} (${accountType})`, error);
      throw error;
    }
  }

  // ✅ 移除账户的限流状态
  async removeAccountRateLimit(accountId, accountType) {
    try {
      if (accountType === 'gemini') {
        await geminiAccountService.setAccountRateLimited(accountId, false);
      }

      return { success: true };
    } catch (error) {
      logger.error(`❌ Failed to remove rate limit for account: ${accountId} (${accountType})`, error);
      throw error;
    }
  }

  // 🔍 检查账户是否处于限流状态
  async isAccountRateLimited(accountId) {
    try {
      const account = await geminiAccountService.getAccount(accountId);
      if (!account) return false;
      
      if (account.rateLimitStatus === 'limited' && account.rateLimitedAt) {
        const limitedAt = new Date(account.rateLimitedAt).getTime();
        const now = Date.now();
        const limitDuration = 60 * 60 * 1000; // 1小时
        
        return now < (limitedAt + limitDuration);
      }
      return false;
    } catch (error) {
      logger.error(`❌ Failed to check rate limit status: ${accountId}`, error);
      return false;
    }
  }

  // 👥 从分组中选择账户
  async selectAccountFromGroup(groupId, sessionHash = null, requestedModel = null) {
    try {
      // 获取分组信息
      const group = await accountGroupService.getGroup(groupId);
      if (!group) {
        throw new Error(`Group ${groupId} not found`);
      }
      
      if (group.platform !== 'gemini') {
        throw new Error(`Group ${group.name} is not a Gemini group`);
      }

      logger.info(`👥 Selecting account from Gemini group: ${group.name}`);

      // 如果有会话哈希，检查是否有已映射的账户
      if (sessionHash) {
        const mappedAccount = await this._getSessionMapping(sessionHash);
        if (mappedAccount) {
          // 验证映射的账户是否属于这个分组
          const memberIds = await accountGroupService.getGroupMembers(groupId);
          if (memberIds.includes(mappedAccount.accountId)) {
            const isAvailable = await this._isAccountAvailable(mappedAccount.accountId, mappedAccount.accountType);
            if (isAvailable) {
              logger.info(`🎯 Using sticky session account from group: ${mappedAccount.accountId} (${mappedAccount.accountType}) for session ${sessionHash}`);
              return mappedAccount;
            }
          }
          // 如果映射的账户不可用或不在分组中，删除映射
          await this._deleteSessionMapping(sessionHash);
        }
      }

      // 获取分组内的所有账户
      const memberIds = await accountGroupService.getGroupMembers(groupId);
      if (memberIds.length === 0) {
        throw new Error(`Group ${group.name} has no members`);
      }

      const availableAccounts = [];

      // 获取所有成员账户的详细信息
      for (const memberId of memberIds) {
        const account = await geminiAccountService.getAccount(memberId);
        
        if (!account) {
          logger.warn(`⚠️ Gemini account ${memberId} not found in group ${group.name}`);
          continue;
        }

        // 检查账户是否可用
        if (account.isActive === 'true' && 
            account.status !== 'error' && 
            this._isSchedulable(account.schedulable)) {
          
          // 检查token是否过期
          const isExpired = geminiAccountService.isTokenExpired(account);
          if (isExpired && !account.refreshToken) {
            logger.warn(`⚠️ Gemini account ${account.name} in group token expired and no refresh token available`);
            continue;
          }

          // 检查模型支持
          if (requestedModel && account.supportedModels && account.supportedModels.length > 0) {
            // 处理可能带有 models/ 前缀的模型名
            const normalizedModel = requestedModel.replace('models/', '');
            const modelSupported = account.supportedModels.some(model => 
              model.replace('models/', '') === normalizedModel
            );
            if (!modelSupported) {
              logger.debug(`⏭️ Skipping Gemini account ${account.name} in group - doesn't support model ${requestedModel}`);
              continue;
            }
          }
          
          // 检查是否被限流
          const isRateLimited = await this.isAccountRateLimited(account.id);
          if (!isRateLimited) {
            availableAccounts.push({
              ...account,
              accountId: account.id,
              accountType: 'gemini',
              priority: parseInt(account.priority) || 50,
              lastUsedAt: account.lastUsedAt || '0'
            });
          }
        }
      }

      if (availableAccounts.length === 0) {
        throw new Error(`No available accounts in Gemini group ${group.name}`);
      }

      // 使用现有的优先级排序逻辑
      const sortedAccounts = this._sortAccountsByPriority(availableAccounts);

      // 选择第一个账户
      const selectedAccount = sortedAccounts[0];

      // 如果有会话哈希，建立新的映射
      if (sessionHash) {
        await this._setSessionMapping(sessionHash, selectedAccount.accountId, selectedAccount.accountType);
        logger.info(`🎯 Created new sticky session mapping in group: ${selectedAccount.name} (${selectedAccount.accountId}, ${selectedAccount.accountType}) for session ${sessionHash}`);
      }

      logger.info(`🎯 Selected account from Gemini group ${group.name}: ${selectedAccount.name} (${selectedAccount.accountId}, ${selectedAccount.accountType}) with priority ${selectedAccount.priority}`);
      
      return {
        accountId: selectedAccount.accountId,
        accountType: selectedAccount.accountType
      };
    } catch (error) {
      logger.error(`❌ Failed to select account from Gemini group ${groupId}:`, error);
      throw error;
    }
  }
}

module.exports = new UnifiedGeminiScheduler();