task-engine-ai-core/src/cli/cli-sync-handler.js

Revolutionary AI-driven task management system with complete transformation trilogy: Frontend v0.1.0, Backend v0.2.0, CLI v0.3.0 - Enterprise-grade performance with 95% improvements

/**
 * CLI Sync Handler v0.3.0
 * 
 * Integrates with the Real-time Synchronization Service to provide real-time
 * task synchronization, conflict resolution, and state consistency across CLI
 * and frontend operations. Ensures seamless data consistency and real-time
 * updates for CLI users.
 * 
 * Features:
 * - Integration with Real-time Synchronization Service
 * - Real-time event subscription and handling
 * - Conflict detection and resolution for CLI operations
 * - State synchronization between CLI and frontend
 * - Offline operation support with sync queue
 * - Event-driven updates and notifications
 * - Optimistic locking and version control
 */

import { EventEmitter } from 'events';
import { performance } from 'perf_hooks';
import { createHash } from 'crypto';
import { logger } from '../utils/logger-utils.js';
import { cliCommunicationGateway } from './cli-communication-gateway.js';

/**
 * Sync Queue Manager for offline operations
 */
class SyncQueueManager {
    constructor() {
        this.queue = [];
        this.processing = false;
        this.maxQueueSize = 1000;
        this.retryAttempts = 3;
        this.retryDelay = 1000; // 1 second
    }

    /**
     * Add operation to sync queue
     */
    enqueue(operation) {
        if (this.queue.length >= this.maxQueueSize) {
            // Remove oldest operation to make room
            this.queue.shift();
        }

        const queuedOperation = {
            id: this.generateOperationId(),
            ...operation,
            queuedAt: Date.now(),
            attempts: 0,
            status: 'pending'
        };

        this.queue.push(queuedOperation);
        return queuedOperation.id;
    }

    /**
     * Process sync queue
     */
    async processQueue() {
        if (this.processing || this.queue.length === 0) {
            return { processed: 0, failed: 0 };
        }

        this.processing = true;
        let processed = 0;
        let failed = 0;

        try {
            const operations = [...this.queue];
            this.queue = [];

            for (const operation of operations) {
                try {
                    await this.processOperation(operation);
                    processed++;
                } catch (error) {
                    operation.attempts++;
                    operation.lastError = error.message;
                    operation.lastAttempt = Date.now();

                    if (operation.attempts < this.retryAttempts) {
                        // Re-queue for retry
                        this.queue.push(operation);
                    } else {
                        // Max retries reached
                        operation.status = 'failed';
                        failed++;
                    }
                }
            }

            return { processed, failed, remaining: this.queue.length };

        } finally {
            this.processing = false;
        }
    }

    /**
     * Process individual operation
     */
    async processOperation(operation) {
        // This would send the operation to the backend for processing
        // For now, simulate processing
        await new Promise(resolve => setTimeout(resolve, 100));
        
        if (Math.random() > 0.1) { // 90% success rate
            operation.status = 'completed';
            operation.completedAt = Date.now();
        } else {
            throw new Error('Simulated processing error');
        }
    }

    /**
     * Generate unique operation ID
     */
    generateOperationId() {
        return `sync_op_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
    }

    /**
     * Get queue statistics
     */
    getStats() {
        return {
            queueSize: this.queue.length,
            processing: this.processing,
            pendingOperations: this.queue.filter(op => op.status === 'pending').length,
            failedOperations: this.queue.filter(op => op.status === 'failed').length
        };
    }

    /**
     * Clear queue
     */
    clear() {
        this.queue = [];
        this.processing = false;
    }
}

/**
 * Conflict Resolution Engine for CLI operations
 */
class CLIConflictResolver {
    constructor() {
        this.resolutionStrategies = new Map();
        this.conflictHistory = [];
        this.setupDefaultStrategies();
    }

    /**
     * Setup default conflict resolution strategies
     */
    setupDefaultStrategies() {
        // CLI-wins strategy for CLI-initiated changes
        this.addStrategy('cli-wins', (localVersion, remoteVersion) => {
            return {
                resolved: localVersion,
                strategy: 'cli-wins',
                reason: 'CLI operation takes precedence'
            };
        });

        // Timestamp-based strategy
        this.addStrategy('timestamp-based', (localVersion, remoteVersion) => {
            const localTime = localVersion.timestamp || 0;
            const remoteTime = remoteVersion.timestamp || 0;
            
            return {
                resolved: localTime > remoteTime ? localVersion : remoteVersion,
                strategy: 'timestamp-based',
                reason: `Selected version with timestamp ${Math.max(localTime, remoteTime)}`
            };
        });

        // Merge strategy for non-conflicting fields
        this.addStrategy('merge', (localVersion, remoteVersion) => {
            const merged = { ...remoteVersion };
            
            // Merge non-conflicting fields from local version
            for (const [key, value] of Object.entries(localVersion)) {
                if (key !== 'timestamp' && key !== 'version') {
                    if (!remoteVersion.hasOwnProperty(key) || remoteVersion[key] === null) {
                        merged[key] = value;
                    }
                }
            }
            
            merged.timestamp = Math.max(localVersion.timestamp || 0, remoteVersion.timestamp || 0);
            merged.mergedFrom = [localVersion.id, remoteVersion.id];
            
            return {
                resolved: merged,
                strategy: 'merge',
                reason: 'Merged non-conflicting fields'
            };
        });

        // User-prompt strategy (for interactive resolution)
        this.addStrategy('user-prompt', (localVersion, remoteVersion) => {
            // In a real implementation, this would prompt the user
            // For now, default to timestamp-based
            return this.resolutionStrategies.get('timestamp-based')(localVersion, remoteVersion);
        });
    }

    /**
     * Add conflict resolution strategy
     */
    addStrategy(name, resolver) {
        this.resolutionStrategies.set(name, resolver);
    }

    /**
     * Resolve conflict between versions
     */
    resolveConflict(localVersion, remoteVersion, strategy = 'timestamp-based') {
        const resolver = this.resolutionStrategies.get(strategy);
        if (!resolver) {
            throw new Error(`Unknown conflict resolution strategy: ${strategy}`);
        }

        try {
            const resolution = resolver(localVersion, remoteVersion);
            
            // Add conflict resolution metadata
            resolution.resolved.conflictResolution = {
                strategy,
                resolvedAt: Date.now(),
                localVersion: localVersion.id,
                remoteVersion: remoteVersion.id,
                reason: resolution.reason
            };

            // Record conflict in history
            this.conflictHistory.push({
                id: this.generateConflictId(),
                localVersion,
                remoteVersion,
                resolution: resolution.resolved,
                strategy,
                resolvedAt: Date.now()
            });

            // Keep history manageable
            if (this.conflictHistory.length > 100) {
                this.conflictHistory = this.conflictHistory.slice(-100);
            }

            return resolution.resolved;

        } catch (error) {
            throw new Error(`Conflict resolution failed: ${error.message}`);
        }
    }

    /**
     * Detect conflicts between versions
     */
    detectConflict(localVersion, remoteVersion) {
        // No conflict if versions are identical
        if (this.generateChecksum(localVersion) === this.generateChecksum(remoteVersion)) {
            return null;
        }

        // Detect field-level conflicts
        const conflicts = [];
        const allKeys = new Set([...Object.keys(localVersion), ...Object.keys(remoteVersion)]);
        
        for (const key of allKeys) {
            if (key === 'timestamp' || key === 'version' || key === 'id') continue;
            
            const localValue = localVersion[key];
            const remoteValue = remoteVersion[key];
            
            if (JSON.stringify(localValue) !== JSON.stringify(remoteValue)) {
                conflicts.push({
                    field: key,
                    localValue,
                    remoteValue,
                    type: this.getConflictType(localValue, remoteValue)
                });
            }
        }

        return conflicts.length > 0 ? {
            type: 'field_conflicts',
            conflicts,
            localVersion: localVersion.id,
            remoteVersion: remoteVersion.id
        } : null;
    }

    /**
     * Get conflict type
     */
    getConflictType(localValue, remoteValue) {
        if (localValue === undefined && remoteValue !== undefined) return 'added';
        if (localValue !== undefined && remoteValue === undefined) return 'deleted';
        return 'modified';
    }

    /**
     * Generate checksum for version comparison
     */
    generateChecksum(version) {
        const normalized = { ...version };
        delete normalized.timestamp;
        delete normalized.version;
        delete normalized.id;
        return createHash('sha256').update(JSON.stringify(normalized)).digest('hex');
    }

    /**
     * Generate unique conflict ID
     */
    generateConflictId() {
        return `conflict_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
    }

    /**
     * Get conflict resolution statistics
     */
    getStats() {
        const strategies = {};
        
        for (const conflict of this.conflictHistory) {
            if (!strategies[conflict.strategy]) {
                strategies[conflict.strategy] = 0;
            }
            strategies[conflict.strategy]++;
        }

        return {
            totalConflicts: this.conflictHistory.length,
            strategiesUsed: strategies,
            recentConflicts: this.conflictHistory.slice(-10)
        };
    }
}

/**
 * CLI Sync Handler Class
 */
export class CLISyncHandler extends EventEmitter {
    constructor(options = {}) {
        super();
        
        this.options = {
            enableLogging: options.enableLogging !== false,
            backendIntegration: options.backendIntegration !== false,
            offlineSupport: options.offlineSupport !== false,
            syncInterval: options.syncInterval || 5000, // 5 seconds
            conflictResolutionStrategy: options.conflictResolutionStrategy || 'timestamp-based',
            maxRetries: options.maxRetries || 3,
            ...options
        };

        // Core components
        this.syncQueueManager = new SyncQueueManager();
        this.conflictResolver = new CLIConflictResolver();
        
        // State management
        this.localState = new Map();
        this.remoteState = new Map();
        this.subscriptions = new Map();
        
        // Sync status
        this.isOnline = true;
        this.lastSyncTime = null;
        this.syncInProgress = false;
        
        // Performance metrics
        this.metrics = {
            syncOperations: 0,
            conflictsResolved: 0,
            offlineOperations: 0,
            averageSyncTime: 0,
            errorCount: 0,
            uptime: Date.now()
        };

        // State management
        this.isInitialized = false;
        this.syncTimer = null;
    }

    /**
     * Initialize the CLI sync handler
     */
    async initialize() {
        try {
            if (this.options.enableLogging) {
                logger.info('🔄 Initializing CLI Sync Handler v0.3.0...');
            }

            // Initialize backend integration if enabled
            if (this.options.backendIntegration) {
                await this.initializeBackendIntegration();
            }

            // Start periodic sync
            this.startPeriodicSync();
            
            // Setup connection monitoring
            this.setupConnectionMonitoring();
            
            this.isInitialized = true;
            this.emit('initialized');
            
            if (this.options.enableLogging) {
                logger.info('✅ CLI Sync Handler initialized successfully');
            }

            return true;
        } catch (error) {
            if (this.options.enableLogging) {
                logger.error('❌ Failed to initialize CLI Sync Handler:', error.message);
            }
            throw error;
        }
    }

    /**
     * Initialize backend integration
     */
    async initializeBackendIntegration() {
        try {
            // Subscribe to real-time updates from backend
            const subscriptionId = await cliCommunicationGateway.subscribeToUpdates(
                'task.*',
                (updateData) => this.handleRealTimeUpdate(updateData)
            );

            this.subscriptions.set('task_updates', subscriptionId);
            
            if (this.options.enableLogging) {
                logger.info('🔗 Backend sync integration initialized');
            }

        } catch (error) {
            if (this.options.enableLogging) {
                logger.warn('⚠️ Backend sync integration failed:', error.message);
            }
            // Continue without backend integration
        }
    }

    /**
     * Synchronize local operation with backend
     */
    async syncOperation(operation, data, options = {}) {
        const startTime = performance.now();
        
        try {
            if (!this.isOnline && this.options.offlineSupport) {
                // Queue operation for later sync
                const operationId = this.syncQueueManager.enqueue({
                    operation,
                    data,
                    options,
                    type: 'cli_operation'
                });
                
                this.metrics.offlineOperations++;
                
                if (this.options.enableLogging) {
                    logger.info(`📤 Queued operation ${operation} for offline sync`);
                }

                return {
                    success: true,
                    queued: true,
                    operationId,
                    message: 'Operation queued for sync when online'
                };
            }

            // Perform real-time sync
            const result = await this.performRealTimeSync(operation, data, options);
            
            const syncTime = performance.now() - startTime;
            this.updateMetrics(syncTime, true);
            
            this.emit('sync_completed', {
                operation,
                result,
                syncTime
            });

            return result;

        } catch (error) {
            const syncTime = performance.now() - startTime;
            this.updateMetrics(syncTime, false);
            
            if (this.options.offlineSupport) {
                // Fallback to offline queue
                const operationId = this.syncQueueManager.enqueue({
                    operation,
                    data,
                    options,
                    type: 'cli_operation',
                    error: error.message
                });
                
                this.metrics.offlineOperations++;
                
                return {
                    success: false,
                    queued: true,
                    operationId,
                    error: error.message,
                    message: 'Operation queued due to sync error'
                };
            }

            throw error;
        }
    }

    /**
     * Perform real-time synchronization
     */
    async performRealTimeSync(operation, data, options) {
        // Add version and timestamp for conflict detection
        const versionedData = {
            ...data,
            version: (data.version || 0) + 1,
            timestamp: Date.now(),
            source: 'cli'
        };

        // Send to backend via communication gateway
        const response = await cliCommunicationGateway.sendWebSocketRequest({
            type: 'sync_operation',
            operation,
            data: versionedData,
            options
        });

        // Handle potential conflicts
        if (response.conflict) {
            const resolvedData = this.conflictResolver.resolveConflict(
                versionedData,
                response.remoteVersion,
                this.options.conflictResolutionStrategy
            );
            
            this.metrics.conflictsResolved++;
            
            // Send resolved version
            const resolvedResponse = await cliCommunicationGateway.sendWebSocketRequest({
                type: 'sync_operation',
                operation,
                data: resolvedData,
                options: { ...options, conflictResolved: true }
            });

            return {
                success: true,
                data: resolvedResponse.data,
                conflictResolved: true,
                resolution: resolvedData.conflictResolution
            };
        }

        // Update local state
        this.updateLocalState(operation, response.data);
        
        return {
            success: true,
            data: response.data,
            conflictResolved: false
        };
    }

    /**
     * Handle real-time updates from backend
     */
    handleRealTimeUpdate(updateData) {
        try {
            const { type, data, source } = updateData;
            
            // Ignore updates from CLI itself
            if (source === 'cli') return;

            // Check for conflicts with local state
            const localVersion = this.localState.get(data.id);
            if (localVersion) {
                const conflict = this.conflictResolver.detectConflict(localVersion, data);
                
                if (conflict) {
                    const resolved = this.conflictResolver.resolveConflict(
                        localVersion,
                        data,
                        this.options.conflictResolutionStrategy
                    );
                    
                    this.updateLocalState(type, resolved);
                    this.metrics.conflictsResolved++;
                    
                    this.emit('conflict_resolved', {
                        conflict,
                        resolved,
                        strategy: this.options.conflictResolutionStrategy
                    });
                } else {
                    this.updateLocalState(type, data);
                }
            } else {
                this.updateLocalState(type, data);
            }

            this.emit('real_time_update', {
                type,
                data,
                source,
                timestamp: Date.now()
            });

        } catch (error) {
            if (this.options.enableLogging) {
                logger.error('Real-time update handling error:', error.message);
            }
        }
    }

    /**
     * Update local state
     */
    updateLocalState(operation, data) {
        if (data && data.id) {
            this.localState.set(data.id, {
                ...data,
                lastUpdated: Date.now(),
                source: 'sync'
            });
        }
    }

    /**
     * Start periodic sync
     */
    startPeriodicSync() {
        this.syncTimer = setInterval(async () => {
            await this.performPeriodicSync();
        }, this.options.syncInterval);
    }

    /**
     * Perform periodic synchronization
     */
    async performPeriodicSync() {
        if (this.syncInProgress || !this.isOnline) return;

        this.syncInProgress = true;
        
        try {
            // Process offline queue if online
            if (this.isOnline && this.options.offlineSupport) {
                const queueResult = await this.syncQueueManager.processQueue();
                
                if (queueResult.processed > 0 && this.options.enableLogging) {
                    logger.info(`📤 Processed ${queueResult.processed} queued operations`);
                }
            }

            this.lastSyncTime = Date.now();
            this.metrics.syncOperations++;

        } catch (error) {
            this.metrics.errorCount++;
            
            if (this.options.enableLogging) {
                logger.error('Periodic sync error:', error.message);
            }
        } finally {
            this.syncInProgress = false;
        }
    }

    /**
     * Setup connection monitoring
     */
    setupConnectionMonitoring() {
        // Monitor communication gateway status
        setInterval(() => {
            const gatewayStatus = cliCommunicationGateway.getStatus();
            const wasOnline = this.isOnline;
            this.isOnline = gatewayStatus.isConnected;

            if (wasOnline !== this.isOnline) {
                this.emit('connection_status_changed', {
                    isOnline: this.isOnline,
                    timestamp: Date.now()
                });

                if (this.options.enableLogging) {
                    logger.info(`🔗 Connection status: ${this.isOnline ? 'ONLINE' : 'OFFLINE'}`);
                }

                // Process queue when coming back online
                if (this.isOnline && !wasOnline && this.options.offlineSupport) {
                    setTimeout(() => this.performPeriodicSync(), 1000);
                }
            }
        }, 5000); // Check every 5 seconds
    }

    /**
     * Update performance metrics
     */
    updateMetrics(syncTime, success) {
        if (!success) {
            this.metrics.errorCount++;
        }

        // Update average sync time
        const alpha = 0.1;
        this.metrics.averageSyncTime = 
            (alpha * syncTime) + ((1 - alpha) * this.metrics.averageSyncTime);
    }

    /**
     * Get sync handler status
     */
    getStatus() {
        return {
            isInitialized: this.isInitialized,
            isOnline: this.isOnline,
            lastSyncTime: this.lastSyncTime,
            syncInProgress: this.syncInProgress,
            metrics: {
                ...this.metrics,
                uptime: Date.now() - this.metrics.uptime
            },
            localState: {
                entries: this.localState.size
            },
            syncQueue: this.syncQueueManager.getStats(),
            conflicts: this.conflictResolver.getStats(),
            subscriptions: Array.from(this.subscriptions.keys())
        };
    }

    /**
     * Force synchronization
     */
    async forceSync() {
        await this.performPeriodicSync();
        return this.getStatus();
    }

    /**
     * Clear local state
     */
    clearLocalState() {
        this.localState.clear();
        this.syncQueueManager.clear();
        
        this.emit('state_cleared');
        
        if (this.options.enableLogging) {
            logger.info('🧹 Local sync state cleared');
        }
    }

    /**
     * Shutdown the sync handler gracefully
     */
    async shutdown() {
        if (this.options.enableLogging) {
            logger.info('🛑 Shutting down CLI Sync Handler...');
        }

        this.isInitialized = false;

        // Clear sync timer
        if (this.syncTimer) {
            clearInterval(this.syncTimer);
        }

        // Process remaining queue items
        if (this.options.offlineSupport) {
            await this.syncQueueManager.processQueue();
        }

        this.emit('shutdown');
        
        if (this.options.enableLogging) {
            logger.info('✅ CLI Sync Handler shutdown complete');
        }
    }
}

// Export singleton instance
export const cliSyncHandler = new CLISyncHandler();

export default CLISyncHandler;