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-- Traditional PostgreSQL backup approach - complex and time-consuming

-- Full database backup (blocks database during backup)
pg_dump --host=localhost --port=5432 --username=postgres \
  --format=custom --blobs --verbose --file=full_backup_20240130.dump \
  --schema=public ecommerce_db;

-- Problems with traditional full backups:
-- 1. Database blocking during backup operations
-- 2. Exponentially growing backup sizes
-- 3. Long recovery times for large databases
-- 4. No granular recovery options
-- 5. Complex coordination across multiple database instances
-- 6. Limited point-in-time recovery capabilities
-- 7. Expensive storage requirements for frequent backups
-- 8. Manual intervention required for disaster recovery scenarios

-- Incremental backup simulation (requires complex custom scripting)
BEGIN;

-- Create backup tracking table
CREATE TABLE IF NOT EXISTS backup_tracking (
    backup_id SERIAL PRIMARY KEY,
    backup_type VARCHAR(20) NOT NULL, -- full, incremental, differential
    backup_timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_lsn BIGINT,
    backup_size_bytes BIGINT,
    backup_location TEXT NOT NULL,
    backup_status VARCHAR(20) DEFAULT 'in_progress',
    completion_time TIMESTAMP,
    verification_status VARCHAR(20),
    retention_until TIMESTAMP
);

-- Track WAL position for incremental backups
CREATE TABLE IF NOT EXISTS wal_tracking (
    tracking_id SERIAL PRIMARY KEY,
    checkpoint_timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    wal_position BIGINT NOT NULL,
    transaction_count BIGINT,
    database_size_bytes BIGINT,
    active_connections INTEGER
);

COMMIT;

-- Complex stored procedure for incremental backup coordination
CREATE OR REPLACE FUNCTION perform_incremental_backup(
    backup_location TEXT,
    compression_level INTEGER DEFAULT 6
)
RETURNS TABLE (
    backup_id INTEGER,
    backup_size_bytes BIGINT,
    duration_seconds INTEGER,
    success BOOLEAN
) AS $$
DECLARE
    current_lsn BIGINT;
    last_backup_lsn BIGINT;
    backup_start_time TIMESTAMP := clock_timestamp();
    new_backup_id INTEGER;
    backup_command TEXT;
    backup_result INTEGER;
BEGIN
    -- Get current WAL position
    SELECT pg_current_wal_lsn() INTO current_lsn;

    -- Get last backup LSN
    SELECT COALESCE(MAX(last_lsn), 0) 
    INTO last_backup_lsn 
    FROM backup_tracking 
    WHERE backup_status = 'completed';

    -- Check if incremental backup is needed
    IF current_lsn <= last_backup_lsn THEN
        RAISE NOTICE 'No changes since last backup, skipping incremental backup';
        RETURN;
    END IF;

    -- Create backup record
    INSERT INTO backup_tracking (
        backup_type, 
        last_lsn, 
        backup_location
    ) 
    VALUES (
        'incremental', 
        current_lsn, 
        backup_location
    ) 
    RETURNING backup_id INTO new_backup_id;

    -- Perform incremental backup (simplified - actual implementation much more complex)
    -- This would require complex WAL shipping and parsing logic
    backup_command := format(
        'pg_basebackup --host=localhost --username=postgres --wal-method=stream --compress=%s --format=tar --pgdata=%s/incremental_%s',
        compression_level,
        backup_location,
        new_backup_id
    );

    -- Execute backup command (in real implementation)
    -- SELECT * FROM system_command(backup_command) INTO backup_result;
    backup_result := 0; -- Simulate success

    IF backup_result = 0 THEN
        -- Update backup record with completion
        UPDATE backup_tracking 
        SET 
            backup_status = 'completed',
            completion_time = clock_timestamp(),
            backup_size_bytes = pg_database_size(current_database())
        WHERE backup_id = new_backup_id;

        -- Record WAL tracking information
        INSERT INTO wal_tracking (
            wal_position,
            transaction_count,
            database_size_bytes,
            active_connections
        ) VALUES (
            current_lsn,
            (SELECT sum(xact_commit + xact_rollback) FROM pg_stat_database),
            pg_database_size(current_database()),
            (SELECT count(*) FROM pg_stat_activity WHERE state = 'active')
        );

        RETURN QUERY SELECT 
            new_backup_id,
            pg_database_size(current_database()),
            EXTRACT(SECONDS FROM clock_timestamp() - backup_start_time)::INTEGER,
            TRUE;
    ELSE
        -- Mark backup as failed
        UPDATE backup_tracking 
        SET backup_status = 'failed' 
        WHERE backup_id = new_backup_id;

        RETURN QUERY SELECT 
            new_backup_id,
            0::BIGINT,
            EXTRACT(SECONDS FROM clock_timestamp() - backup_start_time)::INTEGER,
            FALSE;
    END IF;
END;
$$ LANGUAGE plpgsql;

-- Point-in-time recovery simulation (extremely complex in traditional systems)
CREATE OR REPLACE FUNCTION simulate_point_in_time_recovery(
    target_timestamp TIMESTAMP,
    recovery_location TEXT
)
RETURNS TABLE (
    recovery_success BOOLEAN,
    recovered_to_timestamp TIMESTAMP,
    recovery_duration_minutes INTEGER,
    data_loss_minutes INTEGER
) AS $$
DECLARE
    base_backup_id INTEGER;
    target_lsn BIGINT;
    recovery_start_time TIMESTAMP := clock_timestamp();
    actual_recovery_timestamp TIMESTAMP;
BEGIN
    -- Find appropriate base backup
    SELECT backup_id 
    INTO base_backup_id
    FROM backup_tracking 
    WHERE backup_timestamp <= target_timestamp 
      AND backup_status = 'completed'
      AND backup_type IN ('full', 'differential')
    ORDER BY backup_timestamp DESC 
    LIMIT 1;

    IF base_backup_id IS NULL THEN
        RAISE EXCEPTION 'No suitable base backup found for timestamp %', target_timestamp;
    END IF;

    -- Find target LSN from WAL tracking
    SELECT wal_position 
    INTO target_lsn
    FROM wal_tracking 
    WHERE checkpoint_timestamp <= target_timestamp
    ORDER BY checkpoint_timestamp DESC 
    LIMIT 1;

    -- Simulate complex recovery process
    -- In reality, this involves:
    -- 1. Restoring base backup
    -- 2. Applying WAL files up to target point
    -- 3. Complex validation and consistency checks
    -- 4. Service coordination and failover

    -- Simulate recovery time based on data size and complexity
    PERFORM pg_sleep(
        CASE 
            WHEN pg_database_size(current_database()) > 1073741824 THEN 5 -- Large DB: 5+ minutes
            WHEN pg_database_size(current_database()) > 104857600 THEN 2  -- Medium DB: 2+ minutes
            ELSE 0.5 -- Small DB: 30+ seconds
        END
    );

    actual_recovery_timestamp := target_timestamp - INTERVAL '2 minutes'; -- Simulate slight data loss

    RETURN QUERY SELECT 
        TRUE as recovery_success,
        actual_recovery_timestamp,
        EXTRACT(MINUTES FROM clock_timestamp() - recovery_start_time)::INTEGER,
        EXTRACT(MINUTES FROM target_timestamp - actual_recovery_timestamp)::INTEGER;

END;
$$ LANGUAGE plpgsql;

-- Disaster recovery coordination (manual and error-prone)
CREATE OR REPLACE FUNCTION coordinate_disaster_recovery(
    disaster_scenario VARCHAR(100),
    recovery_site_location TEXT,
    maximum_data_loss_minutes INTEGER DEFAULT 15
)
RETURNS TABLE (
    step_number INTEGER,
    step_description TEXT,
    step_status VARCHAR(20),
    step_duration_minutes INTEGER,
    success BOOLEAN
) AS $$
DECLARE
    step_counter INTEGER := 0;
    total_start_time TIMESTAMP := clock_timestamp();
    step_start_time TIMESTAMP;
BEGIN
    -- Step 1: Assess disaster scope
    step_counter := step_counter + 1;
    step_start_time := clock_timestamp();

    -- Simulate disaster assessment
    PERFORM pg_sleep(0.5);

    RETURN QUERY SELECT 
        step_counter,
        'Assess disaster scope and determine recovery requirements',
        'completed',
        EXTRACT(MINUTES FROM clock_timestamp() - step_start_time)::INTEGER,
        TRUE;

    -- Step 2: Activate disaster recovery site
    step_counter := step_counter + 1;
    step_start_time := clock_timestamp();

    PERFORM pg_sleep(2);

    RETURN QUERY SELECT 
        step_counter,
        'Activate disaster recovery site and initialize infrastructure',
        'completed',
        EXTRACT(MINUTES FROM clock_timestamp() - step_start_time)::INTEGER,
        TRUE;

    -- Step 3: Restore latest backup
    step_counter := step_counter + 1;
    step_start_time := clock_timestamp();

    PERFORM pg_sleep(3);

    RETURN QUERY SELECT 
        step_counter,
        'Restore latest full backup to recovery site',
        'completed', 
        EXTRACT(MINUTES FROM clock_timestamp() - step_start_time)::INTEGER,
        TRUE;

    -- Step 4: Apply incremental backups and WAL files
    step_counter := step_counter + 1;
    step_start_time := clock_timestamp();

    PERFORM pg_sleep(1.5);

    RETURN QUERY SELECT 
        step_counter,
        'Apply incremental backups and WAL files for point-in-time recovery',
        'completed',
        EXTRACT(MINUTES FROM clock_timestamp() - step_start_time)::INTEGER,
        TRUE;

    -- Step 5: Validate data consistency and application connectivity
    step_counter := step_counter + 1;
    step_start_time := clock_timestamp();

    PERFORM pg_sleep(1);

    RETURN QUERY SELECT 
        step_counter,
        'Validate data consistency and test application connectivity',
        'completed',
        EXTRACT(MINUTES FROM clock_timestamp() - step_start_time)::INTEGER,
        TRUE;

    -- Step 6: Switch application traffic to recovery site
    step_counter := step_counter + 1;
    step_start_time := clock_timestamp();

    PERFORM pg_sleep(0.5);

    RETURN QUERY SELECT 
        step_counter,
        'Switch application traffic to disaster recovery site',
        'completed',
        EXTRACT(MINUTES FROM clock_timestamp() - step_start_time)::INTEGER,
        TRUE;

END;
$$ LANGUAGE plpgsql;

-- Problems with traditional disaster recovery approaches:
-- 1. Complex manual coordination across multiple systems and teams
-- 2. Long recovery times due to sequential restoration process
-- 3. High risk of human error during crisis situations
-- 4. Limited automation and orchestration capabilities
-- 5. Expensive infrastructure duplication requirements
-- 6. Difficult testing and validation of recovery procedures
-- 7. Poor integration with cloud storage and modern infrastructure
-- 8. Limited granular recovery options for specific collections or datasets
-- 9. Complex dependency management across related database systems
-- 10. High operational overhead for maintaining backup infrastructure

// MongoDB Enterprise Backup and Recovery Management System
const { MongoClient, GridFSBucket } = require('mongodb');
const fs = require('fs');
const path = require('path');
const zlib = require('zlib');
const crypto = require('crypto');

// Advanced MongoDB backup and recovery management system
class MongoEnterpriseBackupManager {
  constructor(connectionUri, options = {}) {
    this.client = new MongoClient(connectionUri);
    this.db = null;
    this.gridFS = null;

    // Backup configuration
    this.config = {
      // Backup strategy settings
      backupStrategy: {
        enableFullBackups: options.backupStrategy?.enableFullBackups !== false,
        enableIncrementalBackups: options.backupStrategy?.enableIncrementalBackups !== false,
        fullBackupInterval: options.backupStrategy?.fullBackupInterval || '7d',
        incrementalBackupInterval: options.backupStrategy?.incrementalBackupInterval || '1h',
        retentionPeriod: options.backupStrategy?.retentionPeriod || '90d',
        compressionEnabled: options.backupStrategy?.compressionEnabled !== false,
        encryptionEnabled: options.backupStrategy?.encryptionEnabled || false
      },

      // Storage configuration
      storageSettings: {
        localBackupPath: options.storageSettings?.localBackupPath || './backups',
        cloudStorageEnabled: options.storageSettings?.cloudStorageEnabled || false,
        cloudProvider: options.storageSettings?.cloudProvider || 'aws', // aws, azure, gcp
        cloudBucket: options.storageSettings?.cloudBucket || 'mongodb-backups',
        storageClass: options.storageSettings?.storageClass || 'standard' // standard, infrequent, archive
      },

      // Recovery configuration
      recoverySettings: {
        enablePointInTimeRecovery: options.recoverySettings?.enablePointInTimeRecovery !== false,
        oplogRetentionHours: options.recoverySettings?.oplogRetentionHours || 72,
        parallelRecoveryThreads: options.recoverySettings?.parallelRecoveryThreads || 4,
        recoveryValidationEnabled: options.recoverySettings?.recoveryValidationEnabled !== false
      },

      // Disaster recovery configuration
      disasterRecovery: {
        enableCrossRegionReplication: options.disasterRecovery?.enableCrossRegionReplication || false,
        replicationRegions: options.disasterRecovery?.replicationRegions || [],
        automaticFailover: options.disasterRecovery?.automaticFailover || false,
        rpoMinutes: options.disasterRecovery?.rpoMinutes || 15, // Recovery Point Objective
        rtoMinutes: options.disasterRecovery?.rtoMinutes || 30   // Recovery Time Objective
      }
    };

    // Backup state tracking
    this.backupState = {
      lastFullBackup: null,
      lastIncrementalBackup: null,
      activeBackupOperations: new Map(),
      backupHistory: new Map(),
      recoveryOperations: new Map()
    };

    // Performance metrics
    this.metrics = {
      totalBackupsCreated: 0,
      totalDataBackedUp: 0,
      totalRecoveryOperations: 0,
      averageBackupTime: 0,
      averageRecoveryTime: 0,
      backupSuccessRate: 100,
      lastBackupTimestamp: null
    };
  }

  async initialize(databaseName) {
    console.log('Initializing MongoDB Enterprise Backup Manager...');

    try {
      await this.client.connect();
      this.db = this.client.db(databaseName);
      this.gridFS = new GridFSBucket(this.db, { bucketName: 'backups' });

      // Setup backup management collections
      await this.setupBackupCollections();

      // Initialize backup storage directories
      await this.initializeBackupStorage();

      // Load existing backup history
      await this.loadBackupHistory();

      // Setup automated backup scheduling if enabled
      if (this.config.backupStrategy.enableFullBackups || 
          this.config.backupStrategy.enableIncrementalBackups) {
        this.setupAutomatedBackups();
      }

      console.log('MongoDB Enterprise Backup Manager initialized successfully');

    } catch (error) {
      console.error('Error initializing backup manager:', error);
      throw error;
    }
  }

  // Create comprehensive full backup
  async createFullBackup(options = {}) {
    console.log('Starting full backup operation...');

    const backupId = this.generateBackupId();
    const startTime = Date.now();

    try {
      // Initialize backup operation tracking
      const backupOperation = {
        backupId: backupId,
        backupType: 'full',
        startTime: new Date(startTime),
        status: 'in_progress',
        collections: [],
        totalDocuments: 0,
        totalSize: 0,
        compressionRatio: 0,
        encryptionEnabled: this.config.backupStrategy.encryptionEnabled
      };

      this.backupState.activeBackupOperations.set(backupId, backupOperation);

      // Get list of collections to backup
      const collections = options.collections || await this.getBackupCollections();
      backupOperation.collections = collections.map(c => c.name);

      console.log(`Backing up ${collections.length} collections...`);

      // Create backup metadata
      const backupMetadata = {
        backupId: backupId,
        backupType: 'full',
        timestamp: new Date(),
        databaseName: this.db.databaseName,
        collections: collections.map(c => ({
          name: c.name,
          documentCount: 0,
          avgDocSize: 0,
          totalSize: 0,
          indexes: []
        })),
        backupSize: 0,
        compressionEnabled: this.config.backupStrategy.compressionEnabled,
        encryptionEnabled: this.config.backupStrategy.encryptionEnabled,
        version: '1.0'
      };

      // Backup each collection with metadata
      for (const collectionInfo of collections) {
        const collectionBackup = await this.backupCollection(
          collectionInfo.name, 
          backupId, 
          'full',
          options
        );

        // Update metadata
        const collectionMeta = backupMetadata.collections.find(c => c.name === collectionInfo.name);
        collectionMeta.documentCount = collectionBackup.documentCount;
        collectionMeta.avgDocSize = collectionBackup.avgDocSize;
        collectionMeta.totalSize = collectionBackup.totalSize;
        collectionMeta.indexes = collectionBackup.indexes;

        backupOperation.totalDocuments += collectionBackup.documentCount;
        backupOperation.totalSize += collectionBackup.totalSize;
      }

      // Backup database metadata and indexes
      await this.backupDatabaseMetadata(backupId, backupMetadata);

      // Create backup manifest
      const backupManifest = await this.createBackupManifest(backupId, backupMetadata);

      // Store backup in GridFS
      await this.storeBackupInGridFS(backupId, backupManifest);

      // Upload to cloud storage if enabled
      if (this.config.storageSettings.cloudStorageEnabled) {
        await this.uploadToCloudStorage(backupId, backupManifest);
      }

      // Calculate final metrics
      const endTime = Date.now();
      const duration = endTime - startTime;

      backupOperation.status = 'completed';
      backupOperation.endTime = new Date(endTime);
      backupOperation.duration = duration;
      backupOperation.compressionRatio = this.calculateCompressionRatio(backupOperation.totalSize, backupManifest.compressedSize);

      // Update backup history
      this.backupState.backupHistory.set(backupId, backupOperation);
      this.backupState.lastFullBackup = backupOperation;
      this.backupState.activeBackupOperations.delete(backupId);

      // Update metrics
      this.updateBackupMetrics(backupOperation);

      // Log backup completion
      await this.logBackupOperation(backupOperation);

      console.log(`Full backup completed successfully: ${backupId}`);
      console.log(`Duration: ${Math.round(duration / 1000)}s, Size: ${Math.round(backupOperation.totalSize / 1024 / 1024)}MB`);

      return {
        backupId: backupId,
        backupType: 'full',
        duration: duration,
        totalSize: backupOperation.totalSize,
        collections: backupOperation.collections.length,
        totalDocuments: backupOperation.totalDocuments,
        compressionRatio: backupOperation.compressionRatio,
        success: true
      };

    } catch (error) {
      console.error(`Full backup failed: ${backupId}`, error);

      // Update backup operation status
      const backupOperation = this.backupState.activeBackupOperations.get(backupId);
      if (backupOperation) {
        backupOperation.status = 'failed';
        backupOperation.error = error.message;
        backupOperation.endTime = new Date();

        // Move to history
        this.backupState.backupHistory.set(backupId, backupOperation);
        this.backupState.activeBackupOperations.delete(backupId);
      }

      throw error;
    }
  }

  // Create incremental backup based on oplog
  async createIncrementalBackup(options = {}) {
    console.log('Starting incremental backup operation...');

    if (!this.backupState.lastFullBackup) {
      throw new Error('No full backup found. Full backup required before incremental backup.');
    }

    const backupId = this.generateBackupId();
    const startTime = Date.now();

    try {
      // Get oplog entries since last backup
      const lastBackupTime = this.backupState.lastIncrementalBackup?.endTime || 
                             this.backupState.lastFullBackup.endTime;

      const oplogEntries = await this.getOplogEntries(lastBackupTime, options);

      console.log(`Processing ${oplogEntries.length} oplog entries for incremental backup...`);

      const backupOperation = {
        backupId: backupId,
        backupType: 'incremental',
        startTime: new Date(startTime),
        status: 'in_progress',
        baseBackupId: this.backupState.lastFullBackup.backupId,
        oplogEntries: oplogEntries.length,
        affectedCollections: new Set(),
        totalSize: 0
      };

      this.backupState.activeBackupOperations.set(backupId, backupOperation);

      // Process oplog entries and create incremental backup data
      const incrementalData = await this.processOplogForBackup(oplogEntries, backupId);

      // Update operation with processed data
      backupOperation.affectedCollections = Array.from(incrementalData.affectedCollections);
      backupOperation.totalSize = incrementalData.totalSize;

      // Create incremental backup manifest
      const incrementalManifest = {
        backupId: backupId,
        backupType: 'incremental',
        timestamp: new Date(),
        baseBackupId: this.backupState.lastFullBackup.backupId,
        oplogStartTime: lastBackupTime,
        oplogEndTime: new Date(),
        oplogEntries: oplogEntries.length,
        affectedCollections: backupOperation.affectedCollections,
        incrementalSize: incrementalData.totalSize
      };

      // Store incremental backup
      await this.storeIncrementalBackup(backupId, incrementalData, incrementalManifest);

      // Upload to cloud storage if enabled
      if (this.config.storageSettings.cloudStorageEnabled) {
        await this.uploadIncrementalToCloud(backupId, incrementalManifest);
      }

      // Complete backup operation
      const endTime = Date.now();
      const duration = endTime - startTime;

      backupOperation.status = 'completed';
      backupOperation.endTime = new Date(endTime);
      backupOperation.duration = duration;

      // Update backup state
      this.backupState.backupHistory.set(backupId, backupOperation);
      this.backupState.lastIncrementalBackup = backupOperation;
      this.backupState.activeBackupOperations.delete(backupId);

      // Update metrics
      this.updateBackupMetrics(backupOperation);

      // Log backup completion
      await this.logBackupOperation(backupOperation);

      console.log(`Incremental backup completed successfully: ${backupId}`);
      console.log(`Duration: ${Math.round(duration / 1000)}s, Oplog entries: ${oplogEntries.length}`);

      return {
        backupId: backupId,
        backupType: 'incremental',
        duration: duration,
        oplogEntries: oplogEntries.length,
        affectedCollections: backupOperation.affectedCollections.length,
        totalSize: backupOperation.totalSize,
        success: true
      };

    } catch (error) {
      console.error(`Incremental backup failed: ${backupId}`, error);

      const backupOperation = this.backupState.activeBackupOperations.get(backupId);
      if (backupOperation) {
        backupOperation.status = 'failed';
        backupOperation.error = error.message;
        backupOperation.endTime = new Date();

        this.backupState.backupHistory.set(backupId, backupOperation);
        this.backupState.activeBackupOperations.delete(backupId);
      }

      throw error;
    }
  }

  // Advanced point-in-time recovery
  async performPointInTimeRecovery(targetTimestamp, options = {}) {
    console.log(`Starting point-in-time recovery to ${targetTimestamp}...`);

    const recoveryId = this.generateRecoveryId();
    const startTime = Date.now();

    try {
      // Find appropriate backup chain for target timestamp
      const backupChain = await this.findBackupChain(targetTimestamp);

      if (!backupChain || backupChain.length === 0) {
        throw new Error(`No suitable backup found for timestamp: ${targetTimestamp}`);
      }

      console.log(`Using backup chain: ${backupChain.map(b => b.backupId).join(' -> ')}`);

      const recoveryOperation = {
        recoveryId: recoveryId,
        recoveryType: 'point_in_time',
        targetTimestamp: targetTimestamp,
        startTime: new Date(startTime),
        status: 'in_progress',
        backupChain: backupChain,
        recoveryDatabase: options.recoveryDatabase || `${this.db.databaseName}_recovery_${recoveryId}`,
        totalSteps: 0,
        completedSteps: 0
      };

      this.backupState.recoveryOperations.set(recoveryId, recoveryOperation);

      // Create recovery database
      const recoveryDb = this.client.db(recoveryOperation.recoveryDatabase);

      // Step 1: Restore base full backup
      console.log('Restoring base full backup...');
      await this.restoreFullBackup(backupChain[0], recoveryDb, recoveryOperation);
      recoveryOperation.completedSteps++;

      // Step 2: Apply incremental backups in sequence
      for (let i = 1; i < backupChain.length; i++) {
        console.log(`Applying incremental backup ${i}/${backupChain.length - 1}...`);
        await this.applyIncrementalBackup(backupChain[i], recoveryDb, recoveryOperation);
        recoveryOperation.completedSteps++;
      }

      // Step 3: Apply oplog entries up to target timestamp
      console.log('Applying oplog entries for point-in-time recovery...');
      await this.applyOplogToTimestamp(targetTimestamp, recoveryDb, recoveryOperation);
      recoveryOperation.completedSteps++;

      // Step 4: Validate recovered database
      if (this.config.recoverySettings.recoveryValidationEnabled) {
        console.log('Validating recovered database...');
        await this.validateRecoveredDatabase(recoveryDb, recoveryOperation);
        recoveryOperation.completedSteps++;
      }

      // Complete recovery operation
      const endTime = Date.now();
      const duration = endTime - startTime;

      recoveryOperation.status = 'completed';
      recoveryOperation.endTime = new Date(endTime);
      recoveryOperation.duration = duration;
      recoveryOperation.actualRecoveryTimestamp = await this.getLatestTimestampFromDb(recoveryDb);

      // Calculate data loss
      const dataLoss = targetTimestamp - recoveryOperation.actualRecoveryTimestamp;
      recoveryOperation.dataLossMs = Math.max(0, dataLoss);

      // Update metrics
      this.updateRecoveryMetrics(recoveryOperation);

      // Log recovery completion
      await this.logRecoveryOperation(recoveryOperation);

      console.log(`Point-in-time recovery completed successfully: ${recoveryId}`);
      console.log(`Recovery database: ${recoveryOperation.recoveryDatabase}`);
      console.log(`Duration: ${Math.round(duration / 1000)}s, Data loss: ${Math.round(dataLoss / 1000)}s`);

      return {
        recoveryId: recoveryId,
        recoveryType: 'point_in_time',
        duration: duration,
        recoveryDatabase: recoveryOperation.recoveryDatabase,
        actualRecoveryTimestamp: recoveryOperation.actualRecoveryTimestamp,
        dataLossMs: recoveryOperation.dataLossMs,
        backupChainLength: backupChain.length,
        success: true
      };

    } catch (error) {
      console.error(`Point-in-time recovery failed: ${recoveryId}`, error);

      const recoveryOperation = this.backupState.recoveryOperations.get(recoveryId);
      if (recoveryOperation) {
        recoveryOperation.status = 'failed';
        recoveryOperation.error = error.message;
        recoveryOperation.endTime = new Date();
      }

      throw error;
    }
  }

  // Disaster recovery orchestration
  async orchestrateDisasterRecovery(disasterScenario, options = {}) {
    console.log(`Orchestrating disaster recovery for scenario: ${disasterScenario}`);

    const recoveryId = this.generateRecoveryId();
    const startTime = Date.now();

    try {
      const disasterRecoveryOperation = {
        recoveryId: recoveryId,
        recoveryType: 'disaster_recovery',
        disasterScenario: disasterScenario,
        startTime: new Date(startTime),
        status: 'in_progress',
        steps: [],
        currentStep: 0,
        recoveryRegion: options.recoveryRegion || 'primary',
        targetRPO: this.config.disasterRecovery.rpoMinutes,
        targetRTO: this.config.disasterRecovery.rtoMinutes
      };

      this.backupState.recoveryOperations.set(recoveryId, disasterRecoveryOperation);

      // Define disaster recovery steps
      const recoverySteps = [
        {
          step: 1,
          description: 'Assess disaster scope and activate recovery procedures',
          action: this.assessDisasterScope.bind(this),
          estimatedDuration: 2
        },
        {
          step: 2, 
          description: 'Initialize disaster recovery infrastructure',
          action: this.initializeRecoveryInfrastructure.bind(this),
          estimatedDuration: 5
        },
        {
          step: 3,
          description: 'Locate and prepare latest backup chain',
          action: this.prepareDisasterRecoveryBackups.bind(this),
          estimatedDuration: 3
        },
        {
          step: 4,
          description: 'Restore database from backup chain',
          action: this.restoreDisasterRecoveryDatabase.bind(this),
          estimatedDuration: 15
        },
        {
          step: 5,
          description: 'Validate data consistency and integrity',
          action: this.validateDisasterRecoveryDatabase.bind(this),
          estimatedDuration: 3
        },
        {
          step: 6,
          description: 'Switch application traffic to recovery site',
          action: this.switchToRecoverySite.bind(this),
          estimatedDuration: 2
        }
      ];

      disasterRecoveryOperation.steps = recoverySteps;
      disasterRecoveryOperation.totalSteps = recoverySteps.length;

      // Execute recovery steps sequentially
      for (const step of recoverySteps) {
        console.log(`Executing step ${step.step}: ${step.description}`);
        disasterRecoveryOperation.currentStep = step.step;

        const stepStartTime = Date.now();

        try {
          await step.action(disasterRecoveryOperation, options);

          step.status = 'completed';
          step.actualDuration = Math.round((Date.now() - stepStartTime) / 1000 / 60);

          console.log(`Step ${step.step} completed in ${step.actualDuration} minutes`);

        } catch (stepError) {
          step.status = 'failed';
          step.error = stepError.message;
          step.actualDuration = Math.round((Date.now() - stepStartTime) / 1000 / 60);

          console.error(`Step ${step.step} failed:`, stepError);
          throw stepError;
        }
      }

      // Complete disaster recovery
      const endTime = Date.now();
      const totalDuration = Math.round((endTime - startTime) / 1000 / 60);

      disasterRecoveryOperation.status = 'completed';
      disasterRecoveryOperation.endTime = new Date(endTime);
      disasterRecoveryOperation.totalDuration = totalDuration;
      disasterRecoveryOperation.rtoAchieved = totalDuration <= this.config.disasterRecovery.rtoMinutes;

      // Update metrics
      this.updateRecoveryMetrics(disasterRecoveryOperation);

      // Log disaster recovery completion
      await this.logRecoveryOperation(disasterRecoveryOperation);

      console.log(`Disaster recovery completed successfully: ${recoveryId}`);
      console.log(`Total duration: ${totalDuration} minutes (RTO target: ${this.config.disasterRecovery.rtoMinutes} minutes)`);

      return {
        recoveryId: recoveryId,
        recoveryType: 'disaster_recovery',
        totalDuration: totalDuration,
        rtoAchieved: disasterRecoveryOperation.rtoAchieved,
        stepsCompleted: recoverySteps.filter(s => s.status === 'completed').length,
        totalSteps: recoverySteps.length,
        success: true
      };

    } catch (error) {
      console.error(`Disaster recovery failed: ${recoveryId}`, error);

      const recoveryOperation = this.backupState.recoveryOperations.get(recoveryId);
      if (recoveryOperation) {
        recoveryOperation.status = 'failed';
        recoveryOperation.error = error.message;
        recoveryOperation.endTime = new Date();
      }

      throw error;
    }
  }

  // Backup individual collection with compression and encryption
  async backupCollection(collectionName, backupId, backupType, options) {
    console.log(`Backing up collection: ${collectionName}`);

    const collection = this.db.collection(collectionName);
    const backupData = {
      collectionName: collectionName,
      backupId: backupId,
      backupType: backupType,
      timestamp: new Date(),
      documents: [],
      indexes: [],
      documentCount: 0,
      totalSize: 0,
      avgDocSize: 0
    };

    try {
      // Get collection stats
      const stats = await collection.stats();
      backupData.documentCount = stats.count || 0;
      backupData.totalSize = stats.size || 0;
      backupData.avgDocSize = backupData.documentCount > 0 ? backupData.totalSize / backupData.documentCount : 0;

      // Backup collection indexes
      const indexes = await collection.listIndexes().toArray();
      backupData.indexes = indexes.filter(idx => idx.name !== '_id_'); // Exclude default _id index

      // Stream collection documents for memory-efficient backup
      const cursor = collection.find({});
      const documents = [];

      while (await cursor.hasNext()) {
        const doc = await cursor.next();
        documents.push(doc);

        // Process in batches to manage memory usage
        if (documents.length >= 1000) {
          await this.processBatch(documents, backupData, backupId, collectionName);
          documents.length = 0; // Clear batch
        }
      }

      // Process remaining documents
      if (documents.length > 0) {
        await this.processBatch(documents, backupData, backupId, collectionName);
      }

      console.log(`Collection backup completed: ${collectionName} (${backupData.documentCount} documents)`);

      return backupData;

    } catch (error) {
      console.error(`Error backing up collection ${collectionName}:`, error);
      throw error;
    }
  }

  // Process document batch with compression and encryption
  async processBatch(documents, backupData, backupId, collectionName) {
    // Serialize documents to JSON
    const batchData = JSON.stringify(documents);

    // Apply compression if enabled
    let processedData = Buffer.from(batchData, 'utf8');
    if (this.config.backupStrategy.compressionEnabled) {
      processedData = zlib.gzipSync(processedData);
    }

    // Apply encryption if enabled  
    if (this.config.backupStrategy.encryptionEnabled) {
      processedData = this.encryptData(processedData);
    }

    // Store batch data (implementation would store to GridFS or file system)
    const batchId = `${backupId}_${collectionName}_${Date.now()}`;
    await this.storeBatch(batchId, processedData);

    backupData.documents.push({
      batchId: batchId,
      documentCount: documents.length,
      compressedSize: processedData.length,
      originalSize: Buffer.byteLength(batchData, 'utf8')
    });
  }

  // Get oplog entries for incremental backup
  async getOplogEntries(fromTimestamp, options = {}) {
    console.log(`Retrieving oplog entries from ${fromTimestamp}...`);

    try {
      const oplogDb = this.client.db('local');
      const oplogCollection = oplogDb.collection('oplog.rs');

      // Query oplog for entries since last backup
      const query = {
        ts: { $gt: fromTimestamp },
        ns: { $regex: `^${this.db.databaseName}\.` }, // Only our database
        op: { $in: ['i', 'u', 'd'] } // Insert, update, delete operations
      };

      // Exclude certain collections from oplog backup
      const excludeCollections = options.excludeCollections || ['backups.files', 'backups.chunks'];
      if (excludeCollections.length > 0) {
        query.ns = {
          $regex: `^${this.db.databaseName}\.`,
          $nin: excludeCollections.map(col => `${this.db.databaseName}.${col}`)
        };
      }

      const oplogEntries = await oplogCollection
        .find(query)
        .sort({ ts: 1 })
        .limit(options.maxEntries || 100000)
        .toArray();

      console.log(`Retrieved ${oplogEntries.length} oplog entries`);

      return oplogEntries;

    } catch (error) {
      console.error('Error retrieving oplog entries:', error);
      throw error;
    }
  }

  // Process oplog entries for incremental backup
  async processOplogForBackup(oplogEntries, backupId) {
    console.log('Processing oplog entries for incremental backup...');

    const incrementalData = {
      backupId: backupId,
      oplogEntries: oplogEntries,
      affectedCollections: new Set(),
      totalSize: 0,
      operationCounts: {
        inserts: 0,
        updates: 0,
        deletes: 0
      }
    };

    // Group oplog entries by collection
    const collectionOps = new Map();

    for (const entry of oplogEntries) {
      const collectionName = entry.ns.split('.')[1];
      incrementalData.affectedCollections.add(collectionName);

      if (!collectionOps.has(collectionName)) {
        collectionOps.set(collectionName, []);
      }
      collectionOps.get(collectionName).push(entry);

      // Count operation types
      switch (entry.op) {
        case 'i': incrementalData.operationCounts.inserts++; break;
        case 'u': incrementalData.operationCounts.updates++; break;  
        case 'd': incrementalData.operationCounts.deletes++; break;
      }
    }

    // Process and store oplog data per collection
    for (const [collectionName, ops] of collectionOps) {
      const collectionOplogData = JSON.stringify(ops);
      let processedData = Buffer.from(collectionOplogData, 'utf8');

      // Apply compression
      if (this.config.backupStrategy.compressionEnabled) {
        processedData = zlib.gzipSync(processedData);
      }

      // Apply encryption
      if (this.config.backupStrategy.encryptionEnabled) {
        processedData = this.encryptData(processedData);
      }

      // Store incremental data
      const incrementalId = `${backupId}_oplog_${collectionName}`;
      await this.storeIncrementalData(incrementalId, processedData);

      incrementalData.totalSize += processedData.length;
    }

    console.log(`Processed oplog for ${incrementalData.affectedCollections.size} collections`);

    return incrementalData;
  }

  // Comprehensive backup analytics and monitoring
  async getBackupAnalytics(timeRange = '30d') {
    console.log('Generating backup and recovery analytics...');

    const timeRanges = {
      '1d': 1,
      '7d': 7,
      '30d': 30,
      '90d': 90
    };

    const days = timeRanges[timeRange] || 30;
    const startDate = new Date(Date.now() - (days * 24 * 60 * 60 * 1000));

    try {
      // Get backup history from database
      const backupHistory = await this.db.collection('backup_operations')
        .find({
          startTime: { $gte: startDate }
        })
        .sort({ startTime: -1 })
        .toArray();

      // Get recovery history
      const recoveryHistory = await this.db.collection('recovery_operations')
        .find({
          startTime: { $gte: startDate }
        })
        .sort({ startTime: -1 })
        .toArray();

      // Calculate analytics
      const analytics = {
        reportGeneratedAt: new Date(),
        timeRange: timeRange,

        // Backup statistics
        backupStatistics: {
          totalBackups: backupHistory.length,
          fullBackups: backupHistory.filter(b => b.backupType === 'full').length,
          incrementalBackups: backupHistory.filter(b => b.backupType === 'incremental').length,
          successfulBackups: backupHistory.filter(b => b.status === 'completed').length,
          failedBackups: backupHistory.filter(b => b.status === 'failed').length,
          successRate: backupHistory.length > 0 
            ? (backupHistory.filter(b => b.status === 'completed').length / backupHistory.length) * 100 
            : 0,

          // Size and performance metrics
          totalDataBackedUp: backupHistory
            .filter(b => b.status === 'completed')
            .reduce((sum, b) => sum + (b.totalSize || 0), 0),
          averageBackupSize: 0,
          averageBackupDuration: 0,
          averageCompressionRatio: 0
        },

        // Recovery statistics  
        recoveryStatistics: {
          totalRecoveryOperations: recoveryHistory.length,
          pointInTimeRecoveries: recoveryHistory.filter(r => r.recoveryType === 'point_in_time').length,
          disasterRecoveries: recoveryHistory.filter(r => r.recoveryType === 'disaster_recovery').length,
          successfulRecoveries: recoveryHistory.filter(r => r.status === 'completed').length,
          failedRecoveries: recoveryHistory.filter(r => r.status === 'failed').length,
          recoverySuccessRate: recoveryHistory.length > 0 
            ? (recoveryHistory.filter(r => r.status === 'completed').length / recoveryHistory.length) * 100 
            : 0,

          // Performance metrics
          averageRecoveryDuration: 0,
          averageDataLoss: 0,
          rtoCompliance: 0,
          rpoCompliance: 0
        },

        // System health indicators
        systemHealth: {
          backupFrequency: this.calculateBackupFrequency(backupHistory),
          storageUtilization: await this.calculateStorageUtilization(),
          lastSuccessfulBackup: backupHistory.find(b => b.status === 'completed'),
          nextScheduledBackup: this.getNextScheduledBackup(),
          alertsAndWarnings: []
        },

        // Detailed backup history
        recentBackups: backupHistory.slice(0, 10),
        recentRecoveries: recoveryHistory.slice(0, 5)
      };

      // Calculate averages
      const completedBackups = backupHistory.filter(b => b.status === 'completed');
      if (completedBackups.length > 0) {
        analytics.backupStatistics.averageBackupSize = 
          analytics.backupStatistics.totalDataBackedUp / completedBackups.length;
        analytics.backupStatistics.averageBackupDuration = 
          completedBackups.reduce((sum, b) => sum + (b.duration || 0), 0) / completedBackups.length;
        analytics.backupStatistics.averageCompressionRatio = 
          completedBackups.reduce((sum, b) => sum + (b.compressionRatio || 1), 0) / completedBackups.length;
      }

      const completedRecoveries = recoveryHistory.filter(r => r.status === 'completed');
      if (completedRecoveries.length > 0) {
        analytics.recoveryStatistics.averageRecoveryDuration = 
          completedRecoveries.reduce((sum, r) => sum + (r.duration || 0), 0) / completedRecoveries.length;
        analytics.recoveryStatistics.averageDataLoss = 
          completedRecoveries.reduce((sum, r) => sum + (r.dataLossMs || 0), 0) / completedRecoveries.length;
      }

      // Generate alerts and warnings
      analytics.systemHealth.alertsAndWarnings = this.generateHealthAlerts(analytics);

      return analytics;

    } catch (error) {
      console.error('Error generating backup analytics:', error);
      throw error;
    }
  }

  // Utility methods
  async setupBackupCollections() {
    // Create indexes for backup management collections
    await this.db.collection('backup_operations').createIndexes([
      { key: { backupId: 1 }, unique: true },
      { key: { backupType: 1, startTime: -1 } },
      { key: { status: 1, startTime: -1 } },
      { key: { startTime: -1 } }
    ]);

    await this.db.collection('recovery_operations').createIndexes([
      { key: { recoveryId: 1 }, unique: true },
      { key: { recoveryType: 1, startTime: -1 } },
      { key: { status: 1, startTime: -1 } }
    ]);
  }

  async initializeBackupStorage() {
    // Create backup storage directories
    if (!fs.existsSync(this.config.storageSettings.localBackupPath)) {
      fs.mkdirSync(this.config.storageSettings.localBackupPath, { recursive: true });
    }
  }

  generateBackupId() {
    return `backup_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
  }

  generateRecoveryId() {
    return `recovery_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
  }

  calculateCompressionRatio(originalSize, compressedSize) {
    return originalSize > 0 ? originalSize / compressedSize : 1;
  }

  encryptData(data) {
    // Simplified encryption - in production, use proper encryption libraries
    const cipher = crypto.createCipher('aes192', 'backup-encryption-key');
    let encrypted = cipher.update(data, 'binary', 'hex');
    encrypted += cipher.final('hex');
    return Buffer.from(encrypted, 'hex');
  }

  async storeBatch(batchId, data) {
    // Store batch data in GridFS
    const uploadStream = this.gridFS.openUploadStream(batchId);
    uploadStream.end(data);
    return new Promise((resolve, reject) => {
      uploadStream.on('finish', resolve);
      uploadStream.on('error', reject);
    });
  }

  async logBackupOperation(backupOperation) {
    await this.db.collection('backup_operations').insertOne({
      ...backupOperation,
      loggedAt: new Date()
    });
  }

  async logRecoveryOperation(recoveryOperation) {
    await this.db.collection('recovery_operations').insertOne({
      ...recoveryOperation,
      loggedAt: new Date()
    });
  }

  // Placeholder methods for complex operations
  async getBackupCollections() { /* Implementation */ return []; }
  async backupDatabaseMetadata(backupId, metadata) { /* Implementation */ }
  async createBackupManifest(backupId, metadata) { /* Implementation */ return {}; }
  async storeBackupInGridFS(backupId, manifest) { /* Implementation */ }
  async uploadToCloudStorage(backupId, manifest) { /* Implementation */ }
  async storeIncrementalBackup(backupId, data, manifest) { /* Implementation */ }
  async findBackupChain(timestamp) { /* Implementation */ return []; }
  async restoreFullBackup(backup, db, operation) { /* Implementation */ }
  async applyIncrementalBackup(backup, db, operation) { /* Implementation */ }
  async applyOplogToTimestamp(timestamp, db, operation) { /* Implementation */ }
  async validateRecoveredDatabase(db, operation) { /* Implementation */ }
  async assessDisasterScope(operation, options) { /* Implementation */ }
  async initializeRecoveryInfrastructure(operation, options) { /* Implementation */ }
  async prepareDisasterRecoveryBackups(operation, options) { /* Implementation */ }
  async restoreDisasterRecoveryDatabase(operation, options) { /* Implementation */ }
  async validateDisasterRecoveryDatabase(operation, options) { /* Implementation */ }
  async switchToRecoverySite(operation, options) { /* Implementation */ }

  updateBackupMetrics(operation) {
    this.metrics.totalBackupsCreated++;
    this.metrics.totalDataBackedUp += operation.totalSize || 0;
    this.metrics.lastBackupTimestamp = operation.endTime;
  }

  updateRecoveryMetrics(operation) {
    this.metrics.totalRecoveryOperations++;
    // Update other recovery metrics
  }
}

// Example usage demonstrating comprehensive backup and recovery
async function demonstrateEnterpriseBackupRecovery() {
  const backupManager = new MongoEnterpriseBackupManager('mongodb://localhost:27017');

  try {
    await backupManager.initialize('production_ecommerce');

    console.log('Performing full backup...');
    const fullBackupResult = await backupManager.createFullBackup();
    console.log('Full backup result:', fullBackupResult);

    // Simulate some data changes
    console.log('Simulating data changes...');
    await new Promise(resolve => setTimeout(resolve, 2000));

    console.log('Performing incremental backup...');
    const incrementalBackupResult = await backupManager.createIncrementalBackup();
    console.log('Incremental backup result:', incrementalBackupResult);

    // Demonstrate point-in-time recovery
    const recoveryTimestamp = new Date(Date.now() - 60000); // 1 minute ago
    console.log('Performing point-in-time recovery...');
    const recoveryResult = await backupManager.performPointInTimeRecovery(recoveryTimestamp);
    console.log('Recovery result:', recoveryResult);

    // Generate analytics report
    const analytics = await backupManager.getBackupAnalytics('30d');
    console.log('Backup Analytics:', JSON.stringify(analytics, null, 2));

  } catch (error) {
    console.error('Backup and recovery demonstration error:', error);
  }
}

module.exports = {
  MongoEnterpriseBackupManager,
  demonstrateEnterpriseBackupRecovery
};