const AdminRepository = require('../../repositories/admin/AdminRepository');
const UserDocumentRepository = require('../../repositories/documents/UserDocumentRepository');
const UserRepository = require('../../repositories/user/UserRepository');
const { s3 } = require('../../utils/exoscaleUploader');
const { GetObjectCommand } = require('@aws-sdk/client-s3');
const { getSignedUrl } = require('@aws-sdk/s3-request-presigner');
const { DeleteObjectCommand } = require('@aws-sdk/client-s3');
const pidusage = require('pidusage');
const os = require('os');
const { logger } = require('../../middleware/logger');

class AdminService {
  static async getUserStats(unitOfWork) {
    logger.info('AdminService.getUserStats:start');
    try {
      const stats = await AdminRepository.getUserStats(unitOfWork.connection);
      logger.info('AdminService.getUserStats:success', stats);
      return stats;
    } catch (error) {
      logger.error('AdminService.getUserStats:error', { error: error.message });
      throw error;
    }
  }

  static async getUserList(unitOfWork) {
    logger.info('AdminService.getUserList:start');
    try {
      const list = await AdminRepository.getUserList(unitOfWork.connection);
      logger.info('AdminService.getUserList:success', { count: list.length });
      return list;
    } catch (error) {
      logger.error('AdminService.getUserList:error', { error: error.message });
      throw error;
    }
  }

  static async getVerificationPendingUsers(unitOfWork) {
    logger.info('AdminService.getVerificationPendingUsers:start');
    try {
      const users = await AdminRepository.getVerificationPendingUsers(unitOfWork.connection);
      logger.info('AdminService.getVerificationPendingUsers:success', { count: users.length });
      return users;
    } catch (error) {
      logger.error('AdminService.getVerificationPendingUsers:error', { error: error.message });
      throw error;
    }
  }

  static async verifyUser(unitOfWork, userId, permissions) {
    logger.info('AdminService.verifyUser:start', { userId, permissions });
    try {
      // 1. Fetch user
      const userRepo = new UserRepository(unitOfWork);
      const user = await userRepo.findUserByEmailOrId(Number(userId));
      if (!user) throw new Error('User not found');
      logger.info('AdminService.verifyUser:user_fetched', { userId });

      // 2. Fetch documents and contracts
      const documents = await AdminRepository.getUserDocuments(unitOfWork.connection, userId);
      const contracts = await AdminRepository.getUserContracts(unitOfWork.connection, userId);
      logger.info('AdminService.verifyUser:documents_fetched', { userId, documentsCount: documents.length, contractsCount: contracts.length });

      // 3. Fetch ID document metadata
      const idDocs = await AdminRepository.getUserIdDocuments(unitOfWork.connection, userId);
      logger.info('AdminService.verifyUser:id_docs_fetched', { userId, idDocsCount: idDocs.length });

      // 4. Generate signed URLs for front/back of ID documents
      const idDocumentsWithUrls = await Promise.all(
        idDocs.map(async doc => {
          let frontUrl = null, backUrl = null;
          if (doc.front_object_storage_id) {
            try {
              const command = new GetObjectCommand({
                Bucket: process.env.EXOSCALE_BUCKET,
                Key: doc.front_object_storage_id
              });
              frontUrl = await getSignedUrl(s3, command, { expiresIn: 900 });
            } catch (err) { frontUrl = null; }
          }
          if (doc.back_object_storage_id) {
            try {
              const command = new GetObjectCommand({
                Bucket: process.env.EXOSCALE_BUCKET,
                Key: doc.back_object_storage_id
              });
              backUrl = await getSignedUrl(s3, command, { expiresIn: 900 });
            } catch (err) { backUrl = null; }
          }
          return { ...doc, frontUrl, backUrl };
        })
      );
      logger.info('AdminService.verifyUser:id_docs_urls_generated', { userId, idDocsCount: idDocumentsWithUrls.length });

      // 5. Update user_status
      await AdminRepository.verifyUser(unitOfWork.connection, userId);
      logger.info('AdminService.verifyUser:user_status_updated', { userId });

      // 6. Assign permissions
      if (permissions.length > 0) {
        await AdminRepository.assignPermissions(unitOfWork.connection, userId, permissions);
        logger.info('AdminService.verifyUser:permissions_assigned', { userId, permissions });
      }

      // 7. Return updated user data
      logger.info('AdminService.verifyUser:success', { userId });
      return {
        message: 'User verified and permissions updated',
        user: user.getPublicData(),
        documents,
        contracts,
        idDocuments: idDocumentsWithUrls
      };
    } catch (error) {
      logger.error('AdminService.verifyUser:error', { userId, error: error.message });
      throw error;
    }
  }

  static async getFullUserAccountDetails(unitOfWork, userId) {
    logger.info('AdminService.getFullUserAccountDetails:start', { userId });
    try {
      const user = await AdminRepository.getUserById(unitOfWork.connection, userId);
      if (!user) throw new Error('User not found');

      const personalProfile = await AdminRepository.getPersonalProfile(unitOfWork.connection, userId);
      const companyProfile = await AdminRepository.getCompanyProfile(unitOfWork.connection, userId);
      const permissions = await AdminRepository.getUserPermissions(unitOfWork.connection, userId);

      logger.info('AdminService.getFullUserAccountDetails:success', { userId });
      return { user, personalProfile, companyProfile, permissions };
    } catch (error) {
      logger.error('AdminService.getFullUserAccountDetails:error', { userId, error: error.message });
      throw error;
    }
  }

  static async updateUserPermissions(unitOfWork, userId, permissions) {
    logger.info('AdminService.updateUserPermissions:start', { userId, permissions });
    try {
      await AdminRepository.updateUserPermissions(unitOfWork.connection, userId, permissions);
      logger.info('AdminService.updateUserPermissions:success', { userId, permissions });
    } catch (error) {
      logger.error('AdminService.updateUserPermissions:error', { userId, error: error.message });
      throw error;
    }
  }

  static async getServerStatus() {
    logger.info('AdminService.getServerStatus:start');
    try {
      const stats = await pidusage(process.pid);
      const uptimeSeconds = process.uptime();
      const uptimeDays = Math.floor(uptimeSeconds / (60 * 60 * 24));
      const uptimeHours = Math.floor((uptimeSeconds % (60 * 60 * 24)) / 3600);
      const totalMem = os.totalmem();

      logger.info('AdminService.getServerStatus:success', { status: 'Online', uptime: { days: uptimeDays, hours: uptimeHours } });
      return {
        status: 'Online',
        uptime: { days: uptimeDays, hours: uptimeHours },
        cpuUsagePercent: Math.round(stats.cpu),
        memory: {
          used: (stats.memory / (1024 ** 3)).toFixed(1),
          total: (totalMem / (1024 ** 3)).toFixed(1)
        },
        logs: []
      };
    } catch (error) {
      logger.error('AdminService.getServerStatus:error', { error: error.message });
      throw error;
    }
  }

  static async deleteUser(unitOfWork, userId) {
    logger.info('AdminService.deleteUser:start', { userId });
    try {
      // 1. Fetch all object storage IDs for user documents
      const docRepo = new UserDocumentRepository(unitOfWork);
      const objectIds = await docRepo.getAllObjectStorageIdsForUser(userId);

      // 2. Delete each document from S3
      for (const obj of objectIds) {
        try {
          if (obj.object_storage_id) {
            await s3.send(new DeleteObjectCommand({
              Bucket: process.env.EXOSCALE_BUCKET,
              Key: obj.object_storage_id
            }));
            logger.info('AdminService.deleteUser:s3_deleted', { userId, objectKey: obj.object_storage_id });
          }
          // For user_id_documents: front/back
          if (obj.front_object_storage_id) {
            await s3.send(new DeleteObjectCommand({
              Bucket: process.env.EXOSCALE_BUCKET,
              Key: obj.front_object_storage_id
            }));
            logger.info('AdminService.deleteUser:s3_deleted', { userId, objectKey: obj.front_object_storage_id });
          }
          if (obj.back_object_storage_id) {
            await s3.send(new DeleteObjectCommand({
              Bucket: process.env.EXOSCALE_BUCKET,
              Key: obj.back_object_storage_id
            }));
            logger.info('AdminService.deleteUser:s3_deleted', { userId, objectKey: obj.back_object_storage_id });
          }
        } catch (err) {
          logger.warn('AdminService.deleteUser:s3_delete_failed', { userId, error: err.message, objectKey: obj.object_storage_id || obj.front_object_storage_id || obj.back_object_storage_id });
        }
      }

      // 3. Delete user from DB (cascades)
      const userRepo = new UserRepository(unitOfWork);
      await userRepo.deleteUserById(userId);

      logger.info('AdminService.deleteUser:success', { userId });
    } catch (error) {
      logger.error('AdminService.deleteUser:error', { userId, error: error.message });
      throw error;
    }
  }
}

module.exports = AdminService;