/**
 * Advanced Workflow Engine
 * Enhanced workflow execution with sophisticated conditional logic, advanced loops, and dynamic modification
 */

import { EventEmitter } from 'node:events';
import { Logger } from '../core/logger.js';
import { EventBus } from '../core/event-bus.js';
import { generateId } from '../utils/helpers.js';

// Enhanced Workflow Types
export interface AdvancedWorkflowStep {
  id: string;
  name: string;
  type: 'task' | 'if-else' | 'switch' | 'while' | 'for' | 'parallel' | 'try-catch' | 'dynamic-task';
  condition?: AdvancedCondition;
  branches?: WorkflowBranch[];
  loop?: LoopConfiguration;
  errorHandling?: ErrorHandlingConfiguration;
  dynamicTaskConfig?: DynamicTaskConfiguration;
  command?: string;
  agentType?: string;
  dependencies: string[];
  timeout?: number;
  retryCount?: number;
  onSuccess?: string;
  onFailure?: string;
  variables?: Record<string, any>;
  metadata: Record<string, any>;
}

export interface AdvancedCondition {
  type: 'expression' | 'script' | 'function' | 'ai-decision';
  expression?: string;
  script?: string;
  function?: string;
  aiPrompt?: string;
  variables?: string[];
  operator?: 'and' | 'or' | 'not';
  conditions?: AdvancedCondition[];
  timeout?: number;
  fallback?: boolean;
}

export interface WorkflowBranch {
  id: string;
  name: string;
  condition: AdvancedCondition;
  steps: AdvancedWorkflowStep[];
  priority: number;
}

export interface LoopConfiguration {
  type: 'while' | 'for' | 'foreach' | 'until' | 'async-parallel' | 'batch';
  condition?: AdvancedCondition;
  maxIterations: number;
  breakCondition?: AdvancedCondition;
  continueCondition?: AdvancedCondition;
  itemsExpression?: string; // For foreach
  batchSize?: number; // For batch processing
  parallel?: boolean;
  maxConcurrency?: number;
  variables?: Record<string, any>;
}

export interface ErrorHandlingConfiguration {
  strategy: 'ignore' | 'retry' | 'fallback' | 'compensate' | 'escalate';
  maxRetries: number;
  retryDelay: number;
  retryBackoff: 'linear' | 'exponential' | 'custom';
  fallbackSteps?: AdvancedWorkflowStep[];
  compensationSteps?: AdvancedWorkflowStep[];
  escalationRules?: EscalationRule[];
  customHandler?: string;
}

export interface DynamicTaskConfiguration {
  taskGenerator: 'expression' | 'function' | 'ai-generation' | 'template';
  generator: string;
  parameters: Record<string, any>;
  validation?: AdvancedCondition;
  maxTasks?: number;
}

export interface EscalationRule {
  condition: AdvancedCondition;
  action: 'notify' | 'reassign' | 'abort' | 'custom';
  target?: string;
  message?: string;
  customHandler?: string;
}

export interface AdvancedWorkflow {
  id: string;
  name: string;
  description: string;
  version: string;
  status: 'draft' | 'active' | 'paused' | 'completed' | 'failed';
  steps: AdvancedWorkflowStep[];
  globalVariables: Record<string, any>;
  globalErrorHandling: ErrorHandlingConfiguration;
  triggers: WorkflowTrigger[];
  schedule?: WorkflowSchedule;
  permissions?: WorkflowPermissions;
  createdAt: number;
  updatedAt: number;
  metadata: Record<string, any>;
}

export interface WorkflowTrigger {
  id: string;
  type: 'manual' | 'scheduled' | 'event' | 'webhook' | 'condition';
  condition?: AdvancedCondition;
  schedule?: string; // Cron expression
  eventType?: string;
  webhookUrl?: string;
  enabled: boolean;
}

export interface WorkflowSchedule {
  enabled: boolean;
  cronExpression: string;
  timezone: string;
  maxRuns?: number;
  startDate?: Date;
  endDate?: Date;
}

export interface WorkflowPermissions {
  view: string[];
  edit: string[];
  execute: string[];
  admin: string[];
}

export interface AdvancedWorkflowExecution {
  id: string;
  workflowId: string;
  status: 'pending' | 'running' | 'paused' | 'completed' | 'failed' | 'cancelled';
  currentStep?: string;
  variables: Record<string, any>;
  stepResults: Record<string, StepResult>;
  logs: ExecutionLog[];
  performance: ExecutionPerformance;
  startedAt: number;
  completedAt?: number;
  pausedAt?: number;
  triggeredBy: string;
  metadata: Record<string, any>;
}

export interface StepResult {
  stepId: string;
  status: 'pending' | 'running' | 'completed' | 'failed' | 'skipped';
  output: any;
  error?: string;
  duration: number;
  retryCount: number;
  variables: Record<string, any>;
  logs: string[];
  startedAt: number;
  completedAt?: number;
}

export interface ExecutionLog {
  timestamp: number;
  level: 'info' | 'warn' | 'error' | 'debug';
  message: string;
  stepId?: string;
  context?: Record<string, any>;
}

export interface ExecutionPerformance {
  totalDuration: number;
  stepDurations: Record<string, number>;
  waitTime: number;
  resourceUsage: Record<string, any>;
  throughput: number;
  efficiency: number;
}

/**
 * Advanced Workflow Engine with enhanced conditional logic and dynamic capabilities
 */
class AdvancedWorkflowEngine extends EventEmitter {
  private logger: Logger;
  private eventBus: EventBus;
  private workflows = new Map<string, AdvancedWorkflow>();
  private executions = new Map<string, AdvancedWorkflowExecution>();
  private conditionEvaluator: ConditionEvaluator;
  private dynamicTaskGenerator: DynamicTaskGenerator;
  private isInitialized = false;

  constructor(
    logger: Logger,
    eventBus: EventBus
  ) {
    super();
    this.logger = logger;
    this.eventBus = eventBus;
    this.conditionEvaluator = new ConditionEvaluator(logger);
    this.dynamicTaskGenerator = new DynamicTaskGenerator(logger);
  }

  async initialize(): Promise<void> {
    if (this.isInitialized) {
      return;
    }

    this.logger.info('Initializing Advanced Workflow Engine...');
    
    // Initialize sub-components
    await this.conditionEvaluator.initialize();
    await this.dynamicTaskGenerator.initialize();

    // Setup event handlers
    this.setupEventHandlers();

    this.isInitialized = true;
    this.logger.info('Advanced Workflow Engine initialized successfully');
  }

  /**
   * Create a new advanced workflow
   */
  async createWorkflow(workflow: Partial<AdvancedWorkflow>): Promise<string> {
    const workflowId = workflow.id || generateId('workflow');
    
    const advancedWorkflow: AdvancedWorkflow = {
      id: workflowId,
      name: workflow.name || 'Untitled Workflow',
      description: workflow.description || '',
      version: workflow.version || '1.0.0',
      status: 'draft',
      steps: workflow.steps || [],
      globalVariables: workflow.globalVariables || {},
      globalErrorHandling: workflow.globalErrorHandling || {
        strategy: 'retry',
        maxRetries: 3,
        retryDelay: 1000,
        retryBackoff: 'exponential'
      },
      triggers: workflow.triggers || [],
      schedule: workflow.schedule,
      permissions: workflow.permissions,
      createdAt: Date.now(),
      updatedAt: Date.now(),
      metadata: workflow.metadata || {}
    };

    this.workflows.set(workflowId, advancedWorkflow);
    
    this.emit('workflow:created', { workflowId, workflow: advancedWorkflow });
    this.logger.info('Created advanced workflow', { workflowId, name: advancedWorkflow.name });
    
    return workflowId;
  }

  /**
   * Execute workflow with advanced conditional logic
   */
  async executeWorkflow(
    workflowId: string, 
    variables: Record<string, any> = {},
    triggeredBy: string = 'manual'
  ): Promise<string> {
    const workflow = this.workflows.get(workflowId);
    if (!workflow) {
      throw new Error(`Workflow not found: ${workflowId}`);
    }

    const executionId = generateId('execution');
    const execution: AdvancedWorkflowExecution = {
      id: executionId,
      workflowId,
      status: 'pending',
      variables: { ...workflow.globalVariables, ...variables },
      stepResults: {},
      logs: [],
      performance: {
        totalDuration: 0,
        stepDurations: {},
        waitTime: 0,
        resourceUsage: {},
        throughput: 0,
        efficiency: 0
      },
      startedAt: Date.now(),
      triggeredBy,
      metadata: {}
    };

    this.executions.set(executionId, execution);
    
    this.emit('execution:started', { executionId, execution });
    this.addLog(execution, 'info', 'Starting workflow execution', 'engine');
    
    // Start execution asynchronously
    this.executeWorkflowAsync(execution, workflow);
    
    return executionId;
  }

  /**
   * Add dynamic step to running workflow
   */
  async addDynamicStep(
    executionId: string,
    stepConfig: Partial<AdvancedWorkflowStep>,
    insertAfter?: string
  ): Promise<string> {
    const execution = this.executions.get(executionId);
    if (!execution || execution.status !== 'running') {
      throw new Error('Cannot add step to non-running execution');
    }

    const workflow = this.workflows.get(execution.workflowId);
    if (!workflow) {
      throw new Error('Workflow not found');
    }

    const stepId = generateId('dynamic-step');
    const newStep: AdvancedWorkflowStep = {
      id: stepId,
      name: stepConfig.name || 'Dynamic Step',
      type: stepConfig.type || 'task',
      condition: stepConfig.condition,
      command: stepConfig.command,
      agentType: stepConfig.agentType,
      dependencies: stepConfig.dependencies || [],
      timeout: stepConfig.timeout,
      retryCount: stepConfig.retryCount,
      variables: stepConfig.variables,
      metadata: { ...stepConfig.metadata, dynamic: true, addedAt: Date.now() }
    };

    // Insert step into workflow
    if (insertAfter) {
      const insertIndex = workflow.steps.findIndex(s => s.id === insertAfter);
      if (insertIndex >= 0) {
        workflow.steps.splice(insertIndex + 1, 0, newStep);
      } else {
        workflow.steps.push(newStep);
      }
    } else {
      workflow.steps.push(newStep);
    }

    workflow.updatedAt = Date.now();

    this.addLog(execution, 'info', `Added dynamic step: ${newStep.name}`, 'engine');
    this.emit('workflow:step-added', { executionId, stepId, step: newStep });

    return stepId;
  }

  /**
   * Remove step from running workflow
   */
  async removeStep(executionId: string, stepId: string): Promise<void> {
    const execution = this.executions.get(executionId);
    if (!execution) {
      throw new Error('Execution not found');
    }

    const workflow = this.workflows.get(execution.workflowId);
    if (!workflow) {
      throw new Error('Workflow not found');
    }

    // Don't allow removal of currently running or completed steps
    const stepResult = execution.stepResults[stepId];
    if (stepResult && ['running', 'completed'].includes(stepResult.status)) {
      throw new Error('Cannot remove running or completed step');
    }

    // Remove from workflow
    workflow.steps = workflow.steps.filter(s => s.id !== stepId);
    workflow.updatedAt = Date.now();

    // Remove from execution if pending
    if (stepResult) {
      delete execution.stepResults[stepId];
    }

    this.addLog(execution, 'info', `Removed step: ${stepId}`, 'engine');
    this.emit('workflow:step-removed', { executionId, stepId });
  }

  /**
   * Pause workflow execution
   */
  async pauseExecution(executionId: string): Promise<void> {
    const execution = this.executions.get(executionId);
    if (!execution || execution.status !== 'running') {
      throw new Error('Cannot pause non-running execution');
    }

    execution.status = 'paused';
    execution.pausedAt = Date.now();

    this.addLog(execution, 'info', 'Workflow execution paused', 'engine');
    this.emit('execution:paused', { executionId, execution });
  }

  /**
   * Resume paused workflow execution
   */
  async resumeExecution(executionId: string): Promise<void> {
    const execution = this.executions.get(executionId);
    if (!execution || execution.status !== 'paused') {
      throw new Error('Cannot resume non-paused execution');
    }

    execution.status = 'running';
    execution.pausedAt = undefined;

    this.addLog(execution, 'info', 'Workflow execution resumed', 'engine');
    this.emit('execution:resumed', { executionId, execution });

    // Continue execution
    const workflow = this.workflows.get(execution.workflowId);
    if (workflow) {
      this.executeWorkflowAsync(execution, workflow);
    }
  }

  /**
   * Get workflow execution status
   */
  getExecution(executionId: string): AdvancedWorkflowExecution | undefined {
    return this.executions.get(executionId);
  }

  /**
   * List all workflows
   */
  listWorkflows(): AdvancedWorkflow[] {
    return Array.from(this.workflows.values());
  }

  /**
   * Get workflow by ID
   */
  getWorkflow(workflowId: string): AdvancedWorkflow | undefined {
    return this.workflows.get(workflowId);
  }

  // Private execution methods

  private async executeWorkflowAsync(
    execution: AdvancedWorkflowExecution,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    try {
      execution.status = 'running';
      
      for (const step of workflow.steps) {
        if (execution.status !== 'running') {
          break; // Paused or cancelled
        }

        await this.executeStep(execution, step, workflow);
      }

      if (execution.status === 'running') {
        execution.status = 'completed';
        execution.completedAt = Date.now();
        execution.performance.totalDuration = execution.completedAt - execution.startedAt;
        
        this.addLog(execution, 'info', 'Workflow execution completed successfully', 'engine');
        this.emit('execution:completed', { executionId: execution.id, execution });
      }

    } catch (error) {
      execution.status = 'failed';
      execution.completedAt = Date.now();
      execution.performance.totalDuration = execution.completedAt - execution.startedAt;
      
      const errorMessage = error instanceof Error ? error.message : String(error);
      this.addLog(execution, 'error', `Workflow execution failed: ${errorMessage}`, 'engine');
      this.emit('execution:failed', { executionId: execution.id, execution, error });
    }
  }

  private async executeStep(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    const stepStartTime = Date.now();
    
    // Check dependencies
    if (!this.checkDependencies(execution, step)) {
      this.addLog(execution, 'warn', `Step dependencies not met: ${step.name}`, step.id);
      return;
    }

    // Initialize step result
    execution.stepResults[step.id] = {
      stepId: step.id,
      status: 'running',
      output: null,
      duration: 0,
      retryCount: 0,
      variables: { ...execution.variables },
      logs: [],
      startedAt: stepStartTime
    };

    execution.currentStep = step.id;
    this.addLog(execution, 'info', `Starting step: ${step.name}`, step.id);

    try {
      // Evaluate step condition if present
      if (step.condition && !await this.conditionEvaluator.evaluate(step.condition, execution.variables)) {
        execution.stepResults[step.id].status = 'skipped';
        execution.stepResults[step.id].completedAt = Date.now();
        execution.stepResults[step.id].duration = Date.now() - stepStartTime;
        this.addLog(execution, 'info', `Step skipped due to condition: ${step.name}`, step.id);
        return;
      }

      // Execute step based on type
      await this.executeStepByType(execution, step, workflow);

      // Mark as completed
      execution.stepResults[step.id].status = 'completed';
      execution.stepResults[step.id].completedAt = Date.now();
      execution.stepResults[step.id].duration = Date.now() - stepStartTime;
      execution.performance.stepDurations[step.id] = execution.stepResults[step.id].duration;

      this.addLog(execution, 'info', `Step completed: ${step.name}`, step.id);
      this.emit('step:completed', { executionId: execution.id, stepId: step.id, result: execution.stepResults[step.id] });

    } catch (error) {
      await this.handleStepError(execution, step, workflow, error);
    }
  }

  private async executeStepByType(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    switch (step.type) {
      case 'task':
        await this.executeTaskStep(execution, step);
        break;
      case 'if-else':
        await this.executeIfElseStep(execution, step, workflow);
        break;
      case 'switch':
        await this.executeSwitchStep(execution, step, workflow);
        break;
      case 'while':
        await this.executeWhileLoop(execution, step, workflow);
        break;
      case 'for':
        await this.executeForLoop(execution, step, workflow);
        break;
      case 'parallel':
        await this.executeParallelStep(execution, step, workflow);
        break;
      case 'try-catch':
        await this.executeTryCatchStep(execution, step, workflow);
        break;
      case 'dynamic-task':
        await this.executeDynamicTaskStep(execution, step, workflow);
        break;
      default:
        throw new Error(`Unknown step type: ${step.type}`);
    }
  }

  private async executeTaskStep(execution: AdvancedWorkflowExecution, step: AdvancedWorkflowStep): Promise<void> {
    // Simulate task execution
    const result = {
      success: true,
      output: `Task ${step.name} executed successfully`,
      metadata: {
        command: step.command,
        agentType: step.agentType,
        executedAt: new Date().toISOString()
      }
    };

    execution.stepResults[step.id].output = result;
    
    // Update variables if specified
    if (step.variables) {
      Object.assign(execution.variables, step.variables);
    }
  }

  private async executeIfElseStep(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    if (!step.branches || step.branches.length === 0) {
      throw new Error('If-else step requires branches');
    }

    // Find matching branch
    for (const branch of step.branches.sort((a, b) => a.priority - b.priority)) {
      if (await this.conditionEvaluator.evaluate(branch.condition, execution.variables)) {
        this.addLog(execution, 'info', `Executing branch: ${branch.name}`, step.id);
        
        // Execute branch steps
        for (const branchStep of branch.steps) {
          await this.executeStep(execution, branchStep, workflow);
        }
        
        execution.stepResults[step.id].output = {
          executedBranch: branch.id,
          branchName: branch.name
        };
        return;
      }
    }

    // No branch matched
    execution.stepResults[step.id].output = {
      executedBranch: null,
      reason: 'No conditions matched'
    };
  }

  private async executeSwitchStep(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    if (!step.branches) {
      throw new Error('Switch step requires branches');
    }

    // Find exact match first, then fallback to condition evaluation
    for (const branch of step.branches) {
      if (await this.conditionEvaluator.evaluate(branch.condition, execution.variables)) {
        this.addLog(execution, 'info', `Executing switch case: ${branch.name}`, step.id);
        
        for (const branchStep of branch.steps) {
          await this.executeStep(execution, branchStep, workflow);
        }
        
        execution.stepResults[step.id].output = {
          executedBranch: branch.id,
          branchName: branch.name
        };
        return;
      }
    }

    // No case matched
    execution.stepResults[step.id].output = {
      executedBranch: null,
      reason: 'No cases matched'
    };
  }

  private async executeWhileLoop(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    if (!step.loop) {
      throw new Error('While loop requires loop configuration');
    }

    const iterations = [];
    let iterationCount = 0;

    while (iterationCount < step.loop.maxIterations) {
      // Check loop condition
      if (step.loop.condition && !await this.conditionEvaluator.evaluate(step.loop.condition, execution.variables)) {
        break;
      }

      // Check break condition
      if (step.loop.breakCondition && await this.conditionEvaluator.evaluate(step.loop.breakCondition, execution.variables)) {
        break;
      }

      // Execute loop body
      const iterationStart = Date.now();
      
      // Check continue condition
      if (step.loop.continueCondition && !await this.conditionEvaluator.evaluate(step.loop.continueCondition, execution.variables)) {
        iterationCount++;
        continue;
      }

      try {
        // Execute nested steps would go here
        // For now, simulate loop iteration
        await new Promise(resolve => setTimeout(resolve, 100));
        
        iterations.push({
          iteration: iterationCount,
          duration: Date.now() - iterationStart,
          variables: { ...execution.variables }
        });

        this.addLog(execution, 'debug', `Completed while loop iteration ${iterationCount}`, step.id);

      } catch (error) {
        this.addLog(execution, 'error', `While loop iteration ${iterationCount} failed: ${error}`, step.id);
        break;
      }

      iterationCount++;
    }

    execution.stepResults[step.id].output = {
      type: 'while-loop',
      iterations: iterations.length,
      details: iterations
    };
  }

  private async executeForLoop(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    if (!step.loop) {
      throw new Error('For loop requires loop configuration');
    }

    const iterations = [];
    
    if (step.loop.type === 'foreach' && step.loop.itemsExpression) {
      // Get items to iterate over
      const items = this.evaluateExpression(step.loop.itemsExpression, execution.variables);
      
      if (Array.isArray(items)) {
        for (let i = 0; i < items.length && i < step.loop.maxIterations; i++) {
          const item = items[i];
          const iterationStart = Date.now();
          
          // Set loop variables
          execution.variables['__loop_index'] = i;
          execution.variables['__loop_item'] = item;
          
          try {
            // Execute loop body (simulated)
            await new Promise(resolve => setTimeout(resolve, 50));
            
            iterations.push({
              iteration: i,
              item,
              duration: Date.now() - iterationStart
            });

            this.addLog(execution, 'debug', `Completed foreach iteration ${i}`, step.id);

          } catch (error) {
            this.addLog(execution, 'error', `Foreach iteration ${i} failed: ${error}`, step.id);
          }
        }
      }
    } else {
      // Standard for loop
      for (let i = 0; i < step.loop.maxIterations; i++) {
        const iterationStart = Date.now();
        execution.variables['__loop_index'] = i;
        
        try {
          // Execute loop body (simulated)
          await new Promise(resolve => setTimeout(resolve, 50));
          
          iterations.push({
            iteration: i,
            duration: Date.now() - iterationStart
          });

          this.addLog(execution, 'debug', `Completed for loop iteration ${i}`, step.id);

        } catch (error) {
          this.addLog(execution, 'error', `For loop iteration ${i} failed: ${error}`, step.id);
        }
      }
    }

    execution.stepResults[step.id].output = {
      type: 'for-loop',
      iterations: iterations.length,
      details: iterations
    };
  }

  private async executeParallelStep(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    if (!step.branches) {
      throw new Error('Parallel step requires branches');
    }

    const maxConcurrency = step.loop?.maxConcurrency || 5;
    const branchPromises: Promise<any>[] = [];
    const results: any[] = [];

    // Execute branches in parallel with concurrency limit
    for (let i = 0; i < step.branches.length; i += maxConcurrency) {
      const batch = step.branches.slice(i, i + maxConcurrency);
      
      const batchPromises = batch.map(async (branch, index) => {
        try {
          const branchStart = Date.now();
          
          // Execute branch steps
          for (const branchStep of branch.steps) {
            await this.executeStep(execution, branchStep, workflow);
          }
          
          return {
            branchId: branch.id,
            branchName: branch.name,
            success: true,
            duration: Date.now() - branchStart
          };
          
        } catch (error) {
          return {
            branchId: branch.id,
            branchName: branch.name,
            success: false,
            error: error instanceof Error ? error.message : String(error),
            duration: Date.now() - Date.now()
          };
        }
      });

      const batchResults = await Promise.all(batchPromises);
      results.push(...batchResults);
    }

    execution.stepResults[step.id].output = {
      type: 'parallel',
      branches: results.length,
      successful: results.filter(r => r.success).length,
      failed: results.filter(r => !r.success).length,
      details: results
    };
  }

  private async executeTryCatchStep(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    const tryBranch = step.branches?.find(b => b.name === 'try');
    const catchBranch = step.branches?.find(b => b.name === 'catch');
    const finallyBranch = step.branches?.find(b => b.name === 'finally');

    let tryResult: any = null;
    let caughtError: any = null;

    // Execute try block
    if (tryBranch) {
      try {
        for (const tryStep of tryBranch.steps) {
          await this.executeStep(execution, tryStep, workflow);
        }
        tryResult = { success: true };
      } catch (error) {
        caughtError = error;
        
        // Execute catch block
        if (catchBranch) {
          execution.variables['__error'] = error instanceof Error ? error.message : String(error);
          
          try {
            for (const catchStep of catchBranch.steps) {
              await this.executeStep(execution, catchStep, workflow);
            }
          } catch (catchError) {
            this.addLog(execution, 'error', `Catch block failed: ${catchError}`, step.id);
          }
        }
      }
    }

    // Execute finally block
    if (finallyBranch) {
      try {
        for (const finallyStep of finallyBranch.steps) {
          await this.executeStep(execution, finallyStep, workflow);
        }
      } catch (finallyError) {
        this.addLog(execution, 'error', `Finally block failed: ${finallyError}`, step.id);
      }
    }

    execution.stepResults[step.id].output = {
      type: 'try-catch',
      tryResult,
      caughtError: caughtError ? (caughtError instanceof Error ? caughtError.message : String(caughtError)) : null,
      executedFinally: !!finallyBranch
    };

    // Re-throw error if it wasn't handled
    if (caughtError && !catchBranch) {
      throw caughtError;
    }
  }

  private async executeDynamicTaskStep(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow
  ): Promise<void> {
    if (!step.dynamicTaskConfig) {
      throw new Error('Dynamic task step requires dynamic task configuration');
    }

    const generatedTasks = await this.dynamicTaskGenerator.generateTasks(
      step.dynamicTaskConfig,
      execution.variables
    );

    const taskResults = [];

    for (const task of generatedTasks) {
      try {
        const taskStart = Date.now();
        
        // Execute generated task (simulated)
        await new Promise(resolve => setTimeout(resolve, 100));
        
        taskResults.push({
          taskId: task.id,
          taskName: task.name,
          success: true,
          duration: Date.now() - taskStart,
          output: `Dynamic task ${task.name} completed`
        });

        this.addLog(execution, 'info', `Completed dynamic task: ${task.name}`, step.id);

      } catch (error) {
        taskResults.push({
          taskId: task.id,
          taskName: task.name,
          success: false,
          error: error instanceof Error ? error.message : String(error)
        });
      }
    }

    execution.stepResults[step.id].output = {
      type: 'dynamic-task',
      generatedTasks: generatedTasks.length,
      completedTasks: taskResults.filter(r => r.success).length,
      failedTasks: taskResults.filter(r => !r.success).length,
      details: taskResults
    };
  }

  // Helper methods

  private checkDependencies(execution: AdvancedWorkflowExecution, step: AdvancedWorkflowStep): boolean {
    return step.dependencies.every(depId => {
      const depResult = execution.stepResults[depId];
      return depResult && depResult.status === 'completed';
    });
  }

  private evaluateExpression(expression: string, variables: Record<string, any>): any {
    try {
      // Simple expression evaluation (in production, use a proper expression engine)
      const context = { ...variables };
      const func = new Function('context', `with(context) { return ${expression}; }`);
      return func(context);
    } catch (error) {
      this.logger.warn('Expression evaluation failed', { expression, error });
      return null;
    }
  }

  private async handleStepError(
    execution: AdvancedWorkflowExecution,
    step: AdvancedWorkflowStep,
    workflow: AdvancedWorkflow,
    error: any
  ): Promise<void> {
    const stepResult = execution.stepResults[step.id];
    stepResult.status = 'failed';
    stepResult.error = error instanceof Error ? error.message : String(error);
    stepResult.completedAt = Date.now();
    stepResult.duration = Date.now() - stepResult.startedAt;

    const errorHandling = step.errorHandling || workflow.globalErrorHandling;

    this.addLog(execution, 'error', `Step failed: ${step.name} - ${stepResult.error}`, step.id);

    // Handle error based on strategy
    switch (errorHandling.strategy) {
      case 'ignore':
        this.addLog(execution, 'info', 'Error ignored, continuing execution', step.id);
        break;
      case 'retry':
        if (stepResult.retryCount < errorHandling.maxRetries) {
          stepResult.retryCount++;
          this.addLog(execution, 'info', `Retrying step (attempt ${stepResult.retryCount})`, step.id);
          
          // Implement retry delay
          await new Promise(resolve => 
            setTimeout(resolve, errorHandling.retryDelay * Math.pow(2, stepResult.retryCount - 1))
          );
          
          // Retry the step
          await this.executeStep(execution, step, workflow);
        } else {
          throw error;
        }
        break;
      case 'fallback':
        if (errorHandling.fallbackSteps) {
          this.addLog(execution, 'info', 'Executing fallback steps', step.id);
          for (const fallbackStep of errorHandling.fallbackSteps) {
            await this.executeStep(execution, fallbackStep, workflow);
          }
        }
        break;
      case 'compensate':
        if (errorHandling.compensationSteps) {
          this.addLog(execution, 'info', 'Executing compensation steps', step.id);
          for (const compensationStep of errorHandling.compensationSteps) {
            await this.executeStep(execution, compensationStep, workflow);
          }
        }
        break;
      case 'escalate':
        this.addLog(execution, 'error', 'Escalating error', step.id);
        this.emit('error:escalated', { executionId: execution.id, stepId: step.id, error });
        throw error;
      default:
        throw error;
    }
  }

  private addLog(
    execution: AdvancedWorkflowExecution,
    level: 'info' | 'warn' | 'error' | 'debug',
    message: string,
    stepId?: string
  ): void {
    const log: ExecutionLog = {
      timestamp: Date.now(),
      level,
      message,
      stepId,
      context: stepId ? { currentStep: execution.currentStep } : undefined
    };

    execution.logs.push(log);
    
    // Also add to step logs if stepId provided
    if (stepId && execution.stepResults[stepId]) {
      execution.stepResults[stepId].logs.push(message);
    }

    this.logger[level](message, { executionId: execution.id, stepId });
  }

  private setupEventHandlers(): void {
    this.eventBus.on('workflow:trigger', async (data: { workflowId: string; variables?: Record<string, any> }) => {
      try {
        await this.executeWorkflow(data.workflowId, data.variables, 'event');
      } catch (error) {
        this.logger.error('Failed to execute triggered workflow', { workflowId: data.workflowId, error });
      }
    });
  }

  async shutdown(): Promise<void> {
    this.logger.info('Shutting down Advanced Workflow Engine...');
    
    // Cancel running executions
    for (const [executionId, execution] of Array.from(this.executions.entries())) {
      if (execution.status === 'running') {
        execution.status = 'cancelled';
        this.emit('execution:cancelled', { executionId, execution });
      }
    }

    await this.conditionEvaluator.shutdown();
    await this.dynamicTaskGenerator.shutdown();

    this.removeAllListeners();
    this.isInitialized = false;
    
    this.logger.info('Advanced Workflow Engine shutdown complete');
  }
}

/**
 * Advanced Condition Evaluator
 */
class ConditionEvaluator {
  private logger: Logger;

  constructor(logger: Logger) {
    this.logger = logger;
  }

  async initialize(): Promise<void> {
    // Initialize any condition evaluation dependencies
  }

  async evaluate(condition: AdvancedCondition, variables: Record<string, any>): Promise<boolean> {
    try {
      switch (condition.type) {
        case 'expression':
          return this.evaluateExpression(condition.expression!, variables);
        case 'script':
          return this.evaluateScript(condition.script!, variables);
        case 'function':
          return this.evaluateFunction(condition.function!, variables);
        case 'ai-decision':
          return this.evaluateAIDecision(condition.aiPrompt!, variables);
        default:
          throw new Error(`Unknown condition type: ${condition.type}`);
      }
    } catch (error) {
      this.logger.warn('Condition evaluation failed', { condition, error });
      return condition.fallback || false;
    }
  }

  private evaluateExpression(expression: string, variables: Record<string, any>): boolean {
    try {
      const context = { ...variables };
      const func = new Function('context', `with(context) { return Boolean(${expression}); }`);
      return func(context);
    } catch (error) {
      throw new Error(`Expression evaluation failed: ${error}`);
    }
  }

  private evaluateScript(script: string, variables: Record<string, any>): boolean {
    try {
      const context = { ...variables };
      const func = new Function('context', script);
      return Boolean(func(context));
    } catch (error) {
      throw new Error(`Script evaluation failed: ${error}`);
    }
  }

  private evaluateFunction(functionName: string, variables: Record<string, any>): boolean {
    // In a real implementation, this would call registered functions
    // For now, simulate function calls
    switch (functionName) {
      case 'isWeekend':
        return new Date().getDay() === 0 || new Date().getDay() === 6;
      case 'hasRequiredData':
        return variables.data !== undefined && variables.data !== null;
      default:
        return false;
    }
  }

  private async evaluateAIDecision(prompt: string, variables: Record<string, any>): Promise<boolean> {
    // In a real implementation, this would call an AI service
    // For now, simulate AI decision making
    await new Promise(resolve => setTimeout(resolve, 100)); // Simulate AI latency
    
    // Simple heuristic: return true if prompt contains "true" or variables suggest success
    return prompt.toLowerCase().includes('true') || 
           Object.values(variables).some(v => v === true || v === 'success');
  }

  async shutdown(): Promise<void> {
    // Cleanup condition evaluator resources
  }
}

/**
 * Dynamic Task Generator
 */
class DynamicTaskGenerator {
  private logger: Logger;

  constructor(logger: Logger) {
    this.logger = logger;
  }

  async initialize(): Promise<void> {
    // Initialize task generation dependencies
  }

  async generateTasks(
    config: DynamicTaskConfiguration,
    variables: Record<string, any>
  ): Promise<Array<{ id: string; name: string; type: string; config: any }>> {
    switch (config.taskGenerator) {
      case 'expression':
        return this.generateFromExpression(config.generator, variables, config.parameters);
      case 'function':
        return this.generateFromFunction(config.generator, variables, config.parameters);
      case 'ai-generation':
        return this.generateFromAI(config.generator, variables, config.parameters);
      case 'template':
        return this.generateFromTemplate(config.generator, variables, config.parameters);
      default:
        throw new Error(`Unknown task generator: ${config.taskGenerator}`);
    }
  }

  private generateFromExpression(
    expression: string,
    variables: Record<string, any>,
    parameters: Record<string, any>
  ): Array<{ id: string; name: string; type: string; config: any }> {
    // Simple expression-based task generation
    const count = parameters.count || 1;
    const tasks = [];

    for (let i = 0; i < count; i++) {
      tasks.push({
        id: generateId(`dynamic-task`),
        name: `Dynamic Task ${i + 1}`,
        type: 'task',
        config: { ...parameters, index: i, variables }
      });
    }

    return tasks;
  }

  private generateFromFunction(
    functionName: string,
    variables: Record<string, any>,
    parameters: Record<string, any>
  ): Array<{ id: string; name: string; type: string; config: any }> {
    // Function-based task generation
    switch (functionName) {
      case 'generateProcessingTasks':
        const items = variables.items || [];
        return items.map((item: any, index: number) => ({
          id: generateId(`process-task`),
          name: `Process ${item.name || index}`,
          type: 'processing',
          config: { item, index, ...parameters }
        }));
      default:
        return [];
    }
  }

  private async generateFromAI(
    prompt: string,
    variables: Record<string, any>,
    parameters: Record<string, any>
  ): Promise<Array<{ id: string; name: string; type: string; config: any }>> {
    // AI-based task generation (simulated)
    await new Promise(resolve => setTimeout(resolve, 200)); // Simulate AI latency

    // Generate tasks based on prompt analysis
    const taskCount = Math.min(parameters.maxTasks || 5, 3);
    const tasks = [];

    for (let i = 0; i < taskCount; i++) {
      tasks.push({
        id: generateId(`ai-task`),
        name: `AI Generated Task ${i + 1}`,
        type: 'ai-task',
        config: { prompt, variables, ...parameters, index: i }
      });
    }

    return tasks;
  }

  private generateFromTemplate(
    templateName: string,
    variables: Record<string, any>,
    parameters: Record<string, any>
  ): Array<{ id: string; name: string; type: string; config: any }> {
    // Template-based task generation
    const templates: Record<string, any> = {
      'data-processing': {
        tasks: [
          { name: 'Validate Input', type: 'validation' },
          { name: 'Transform Data', type: 'transformation' },
          { name: 'Store Results', type: 'storage' }
        ]
      },
      'testing-suite': {
        tasks: [
          { name: 'Unit Tests', type: 'testing' },
          { name: 'Integration Tests', type: 'testing' },
          { name: 'Performance Tests', type: 'testing' }
        ]
      }
    };

    const template = templates[templateName];
    if (!template) {
      return [];
    }

    return template.tasks.map((task: any, index: number) => ({
      id: generateId(`template-task`),
      name: task.name,
      type: task.type,
      config: { ...parameters, templateName, index }
    }));
  }

  async shutdown(): Promise<void> {
    // Cleanup task generator resources
  }
}

export { AdvancedWorkflowEngine, ConditionEvaluator, DynamicTaskGenerator };