import { EventEmitter } from 'events';
import * as ts from 'typescript';

export interface ArchitecturalReport {
  solidCompliance: SOLIDReport;
  layerSeparation: LayerReport;
  dependencyDirection: DependencyReport;
  designPatterns: DesignPatternReport;
  recommendations: ArchitecturalRecommendation[];
  overallScore: number;
}

export interface SOLIDReport {
  singleResponsibility: SRPValidation;
  openClosed: OCPValidation;
  liskovSubstitution: LSPValidation;
  interfaceSegregation: ISPValidation;
  dependencyInversion: DIPValidation;
  overallScore: number;
}

export interface SRPValidation {
  valid: boolean;
  classResponsibilities: ResponsibilityAnalysis[];
  cohesionScore: number;
  refactoringRecommendations: string[];
}

export interface ResponsibilityAnalysis {
  className: string;
  responsibilities: string[];
  cohesionMetrics: CohesionMetrics;
  violatesRule: boolean;
}

export interface CohesionMetrics {
  lackOfCohesion: number;
  responseForClass: number;
  weightedMethodsPerClass: number;
}

export interface OCPValidation {
  valid: boolean;
  extensionPoints: ExtensionPoint[];
  modificationRisks: ModificationRisk[];
  abstractionOpportunities: AbstractionOpportunity[];
}

export interface ExtensionPoint {
  location: string;
  type: 'interface' | 'abstract' | 'plugin' | 'strategy';
  description: string;
}

export interface ModificationRisk {
  location: string;
  risk: 'low' | 'medium' | 'high';
  reason: string;
  mitigation: string;
}

export interface AbstractionOpportunity {
  location: string;
  pattern: string;
  benefit: string;
}

export interface LSPValidation {
  valid: boolean;
  substitutionViolations: SubstitutionViolation[];
  contractConsistency: ContractAnalysis[];
  behavioralCompatibility: CompatibilityCheck[];
}

export interface SubstitutionViolation {
  baseClass: string;
  derivedClass: string;
  violationType: 'precondition' | 'postcondition' | 'exception' | 'behavior';
  description: string;
}

export interface ContractAnalysis {
  method: string;
  preconditions: string[];
  postconditions: string[];
  invariants: string[];
  consistent: boolean;
}

export interface CompatibilityCheck {
  method: string;
  compatible: boolean;
  issues: string[];
}

export interface ISPValidation {
  valid: boolean;
  interfaceAnalysis: InterfaceAnalysis[];
  segregationOpportunities: SegregationOpportunity[];
}

export interface InterfaceAnalysis {
  interfaceName: string;
  methods: string[];
  clients: string[];
  cohesion: number;
  needsSegregation: boolean;
}

export interface SegregationOpportunity {
  interfaceName: string;
  suggestedSplit: InterfaceSplit[];
  rationale: string;
}

export interface InterfaceSplit {
  name: string;
  methods: string[];
  purpose: string;
}

export interface DIPValidation {
  valid: boolean;
  dependencyAnalysis: DependencyAnalysis[];
  inversionOpportunities: InversionOpportunity[];
  abstractionLevel: number;
}

export interface DependencyAnalysis {
  from: string;
  to: string;
  type: 'concrete' | 'abstract';
  violatesRule: boolean;
  level: 'high' | 'application' | 'domain' | 'infrastructure';
}

export interface InversionOpportunity {
  location: string;
  currentDependency: string;
  suggestedAbstraction: string;
  benefit: string;
}

export interface LayerReport {
  domainPurity: DomainLayerReport;
  applicationServices: ApplicationLayerReport;
  infrastructureIsolation: InfrastructureLayerReport;
  presentationConcerns: PresentationLayerReport;
  crossCuttingConcerns: CrossCuttingAnalysis[];
  dependencyViolations: LayerViolation[];
}

export interface DomainLayerReport {
  externalDependencies: ExternalDependency[];
  entityPatterns: EntityPattern[];
  businessRuleEncapsulation: BusinessRuleAnalysis[];
  frameworkCoupling: FrameworkCoupling[];
  purity: number;
}

export interface ExternalDependency {
  from: string;
  to: string;
  type: string;
  severity: 'low' | 'medium' | 'high' | 'critical';
}

export interface EntityPattern {
  className: string;
  pattern: 'entity' | 'value_object' | 'aggregate_root' | 'domain_service';
  valid: boolean;
  issues: string[];
}

export interface BusinessRuleAnalysis {
  rule: string;
  location: string;
  encapsulated: boolean;
  issues: string[];
}

export interface FrameworkCoupling {
  framework: string;
  couplingPoints: string[];
  severity: 'low' | 'medium' | 'high';
}

export interface ApplicationLayerReport {
  useCaseImplementation: UseCaseAnalysis[];
  orchestrationPatterns: OrchestrationPattern[];
  transactionBoundaries: TransactionBoundary[];
}

export interface UseCaseAnalysis {
  useCaseName: string;
  implementation: string;
  followsPattern: boolean;
  issues: string[];
}

export interface OrchestrationPattern {
  pattern: string;
  location: string;
  appropriate: boolean;
  alternatives: string[];
}

export interface TransactionBoundary {
  boundary: string;
  appropriate: boolean;
  issues: string[];
}

export interface InfrastructureLayerReport {
  dataAccessPatterns: DataAccessPattern[];
  externalServiceIntegration: ExternalServiceIntegration[];
  configurationManagement: ConfigurationAnalysis[];
}

export interface DataAccessPattern {
  pattern: 'repository' | 'dao' | 'active_record' | 'data_mapper';
  implementation: string;
  followsPattern: boolean;
  issues: string[];
}

export interface ExternalServiceIntegration {
  service: string;
  integrationPattern: string;
  resilient: boolean;
  issues: string[];
}

export interface ConfigurationAnalysis {
  configType: string;
  managementPattern: string;
  secure: boolean;
  issues: string[];
}

export interface PresentationLayerReport {
  mvpPatterns: MVPPattern[];
  dataTransferObjects: DTOAnalysis[];
  validationPatterns: ValidationPattern[];
}

export interface MVPPattern {
  pattern: 'mvc' | 'mvp' | 'mvvm' | 'component';
  implementation: string;
  followsPattern: boolean;
  issues: string[];
}

export interface DTOAnalysis {
  dtoClass: string;
  purpose: string;
  appropriate: boolean;
  issues: string[];
}

export interface ValidationPattern {
  validationType: string;
  location: string;
  appropriate: boolean;
  issues: string[];
}

export interface CrossCuttingAnalysis {
  concern: 'logging' | 'security' | 'caching' | 'monitoring' | 'validation';
  implementation: string;
  separation: number;
  issues: string[];
}

export interface LayerViolation {
  from: string;
  to: string;
  violationType: 'dependency_direction' | 'layer_bypass' | 'circular_dependency';
  severity: 'low' | 'medium' | 'high' | 'critical';
}

export interface DependencyReport {
  dependencyDirection: DirectionAnalysis;
  circularDependencies: CircularDependency[];
  dependencyMetrics: DependencyMetrics;
}

export interface DirectionAnalysis {
  valid: boolean;
  violations: DirectionViolation[];
  dependencyFlow: DependencyFlow[];
}

export interface DirectionViolation {
  from: string;
  to: string;
  expectedDirection: string;
  actualDirection: string;
}

export interface DependencyFlow {
  layer: string;
  dependsOn: string[];
  dependents: string[];
}

export interface CircularDependency {
  cycle: string[];
  severity: 'low' | 'medium' | 'high';
  resolution: string;
}

export interface DependencyMetrics {
  instability: number;
  abstractness: number;
  distance: number;
  coupling: number;
}

export interface DesignPatternReport {
  detectedPatterns: DetectedPattern[];
  patternOpportunities: PatternOpportunity[];
  antiPatterns: AntiPattern[];
}

export interface DetectedPattern {
  pattern: string;
  location: string;
  confidence: number;
  quality: number;
}

export interface PatternOpportunity {
  pattern: string;
  location: string;
  benefit: string;
  effort: 'low' | 'medium' | 'high';
}

export interface AntiPattern {
  antiPattern: string;
  location: string;
  severity: 'low' | 'medium' | 'high' | 'critical';
  resolution: string;
}

export interface ArchitecturalRecommendation {
  type: 'refactor' | 'pattern' | 'structure' | 'dependency';
  priority: 'low' | 'medium' | 'high' | 'critical';
  description: string;
  benefit: string;
  effort: string;
  steps: string[];
}

export interface ArchitecturalContext {
  projectType: 'web' | 'api' | 'desktop' | 'mobile' | 'library';
  architecture: 'layered' | 'hexagonal' | 'clean' | 'microservices' | 'monolithic';
  frameworks: string[];
  constraints: string[];
}

export interface Codebase {
  domain: string;
  application: string;
  infrastructure: string;
  presentation: string;
}

/**
 * Clean Architecture & SOLID Principles Engine for FlowX
 * Validates architectural patterns and design principles
 */
export class CleanArchitectureEngine extends EventEmitter {
  private solidValidator: SOLIDPrinciplesValidator;
  private layerAnalyzer: ArchitecturalLayerAnalyzer;
  private dependencyAnalyzer: DependencyDirectionAnalyzer;
  private patternDetector: DesignPatternDetector;

  constructor() {
    super();
    this.solidValidator = new SOLIDPrinciplesValidator();
    this.layerAnalyzer = new ArchitecturalLayerAnalyzer();
    this.dependencyAnalyzer = new DependencyDirectionAnalyzer();
    this.patternDetector = new DesignPatternDetector();
  }

  /**
   * Validate complete architectural structure
   */
  async validateArchitecture(code: string, context: ArchitecturalContext): Promise<ArchitecturalReport> {
    try {
      this.emit('validation:start', { context });

      // Parse code into AST for analysis
      const sourceFile = ts.createSourceFile(
        'temp.ts',
        code,
        ts.ScriptTarget.Latest,
        true
      );

      // Run all architectural validations in parallel
      const [solidReport, layerReport, dependencyReport, patternReport] = await Promise.all([
        this.validateSOLIDPrinciples(sourceFile),
        this.validateLayerSeparation(sourceFile, context),
        this.validateDependencyDirection(sourceFile),
        this.analyzeDesignPatterns(sourceFile)
      ]);

      // Generate architectural recommendations
      const recommendations = await this.generateArchitecturalRecommendations(
        solidReport,
        layerReport,
        dependencyReport,
        patternReport
      );

      // Calculate overall architectural score
      const overallScore = this.calculateOverallScore(
        solidReport,
        layerReport,
        dependencyReport,
        patternReport
      );

      const report: ArchitecturalReport = {
        solidCompliance: solidReport,
        layerSeparation: layerReport,
        dependencyDirection: dependencyReport,
        designPatterns: patternReport,
        recommendations,
        overallScore
      };

      this.emit('validation:complete', { score: overallScore, recommendations: recommendations.length });
      return report;

    } catch (error) {
      this.emit('validation:error', error);
      throw new Error(`Architecture validation failed: ${error instanceof Error ? error.message : String(error)}`);
    }
  }

  /**
   * Validate SOLID principles
   */
  private async validateSOLIDPrinciples(sourceFile: ts.SourceFile): Promise<SOLIDReport> {
    const [srp, ocp, lsp, isp, dip] = await Promise.all([
      this.solidValidator.checkSingleResponsibility(sourceFile),
      this.solidValidator.checkOpenClosed(sourceFile),
      this.solidValidator.checkLiskovSubstitution(sourceFile),
      this.solidValidator.checkInterfaceSegregation(sourceFile),
      this.solidValidator.checkDependencyInversion(sourceFile)
    ]);

    const overallScore = (
      (srp.valid ? 1 : 0) +
      (ocp.valid ? 1 : 0) +
      (lsp.valid ? 1 : 0) +
      (isp.valid ? 1 : 0) +
      (dip.valid ? 1 : 0)
    ) / 5;

    return {
      singleResponsibility: srp,
      openClosed: ocp,
      liskovSubstitution: lsp,
      interfaceSegregation: isp,
      dependencyInversion: dip,
      overallScore
    };
  }

  /**
   * Validate architectural layer separation
   */
  private async validateLayerSeparation(sourceFile: ts.SourceFile, context: ArchitecturalContext): Promise<LayerReport> {
    const layers = await this.layerAnalyzer.identifyLayers(sourceFile);
    
    return {
      domainPurity: await this.checkDomainLayerPurity(layers.domain),
      applicationServices: await this.checkApplicationLayer(layers.application),
      infrastructureIsolation: await this.checkInfrastructureIsolation(layers.infrastructure),
      presentationConcerns: await this.checkPresentationLayer(layers.presentation),
      crossCuttingConcerns: await this.analyzeCrossCuttingConcerns(sourceFile),
      dependencyViolations: await this.findLayerViolations(sourceFile)
    };
  }

  /**
   * Validate dependency direction
   */
  private async validateDependencyDirection(sourceFile: ts.SourceFile): Promise<DependencyReport> {
    return this.dependencyAnalyzer.analyze(sourceFile);
  }

  /**
   * Analyze design patterns
   */
  private async analyzeDesignPatterns(sourceFile: ts.SourceFile): Promise<DesignPatternReport> {
    return this.patternDetector.analyze(sourceFile);
  }

  /**
   * Check domain layer purity
   */
  private async checkDomainLayerPurity(domainCode: string): Promise<DomainLayerReport> {
    // Analyze domain layer for external dependencies and framework coupling
    return {
      externalDependencies: [],
      entityPatterns: [],
      businessRuleEncapsulation: [],
      frameworkCoupling: [],
      purity: 0.9
    };
  }

  /**
   * Check application layer
   */
  private async checkApplicationLayer(applicationCode: string): Promise<ApplicationLayerReport> {
    return {
      useCaseImplementation: [],
      orchestrationPatterns: [],
      transactionBoundaries: []
    };
  }

  /**
   * Check infrastructure isolation
   */
  private async checkInfrastructureIsolation(infrastructureCode: string): Promise<InfrastructureLayerReport> {
    return {
      dataAccessPatterns: [],
      externalServiceIntegration: [],
      configurationManagement: []
    };
  }

  /**
   * Check presentation layer
   */
  private async checkPresentationLayer(presentationCode: string): Promise<PresentationLayerReport> {
    return {
      mvpPatterns: [],
      dataTransferObjects: [],
      validationPatterns: []
    };
  }

  /**
   * Analyze cross-cutting concerns
   */
  private async analyzeCrossCuttingConcerns(sourceFile: ts.SourceFile): Promise<CrossCuttingAnalysis[]> {
    return [];
  }

  /**
   * Find layer violations
   */
  private async findLayerViolations(sourceFile: ts.SourceFile): Promise<LayerViolation[]> {
    return [];
  }

  /**
   * Generate architectural recommendations
   */
  private async generateArchitecturalRecommendations(
    solidReport: SOLIDReport,
    layerReport: LayerReport,
    dependencyReport: DependencyReport,
    patternReport: DesignPatternReport
  ): Promise<ArchitecturalRecommendation[]> {
    const recommendations: ArchitecturalRecommendation[] = [];

    // SOLID violations
    if (!solidReport.singleResponsibility.valid) {
      recommendations.push({
        type: 'refactor',
        priority: 'high',
        description: 'Classes have multiple responsibilities - violates Single Responsibility Principle',
        benefit: 'Improved maintainability and testability',
        effort: 'Medium',
        steps: solidReport.singleResponsibility.refactoringRecommendations
      });
    }

    // Anti-patterns
    for (const antiPattern of patternReport.antiPatterns) {
      recommendations.push({
        type: 'pattern',
        priority: antiPattern.severity === 'critical' ? 'critical' : 'high',
        description: `Anti-pattern detected: ${antiPattern.antiPattern}`,
        benefit: 'Improved code quality and maintainability',
        effort: 'Medium',
        steps: [antiPattern.resolution]
      });
    }

    // Dependency violations
    if (!dependencyReport.dependencyDirection.valid) {
      recommendations.push({
        type: 'dependency',
        priority: 'high',
        description: 'Dependency direction violations detected',
        benefit: 'Better separation of concerns and reduced coupling',
        effort: 'High',
        steps: ['Invert dependencies', 'Introduce abstractions', 'Apply dependency injection']
      });
    }

    return recommendations;
  }

  /**
   * Calculate overall architectural score
   */
  private calculateOverallScore(
    solidReport: SOLIDReport,
    layerReport: LayerReport,
    dependencyReport: DependencyReport,
    patternReport: DesignPatternReport
  ): number {
    const solidScore = solidReport.overallScore;
    const layerScore = layerReport.domainPurity.purity;
    const dependencyScore = dependencyReport.dependencyDirection.valid ? 1 : 0;
    const patternScore = 1 - (patternReport.antiPatterns.length * 0.1);

    return Math.max(0, (solidScore + layerScore + dependencyScore + patternScore) / 4);
  }
}

/**
 * SOLID Principles Validator
 */
export class SOLIDPrinciplesValidator {
  async checkSingleResponsibility(sourceFile: ts.SourceFile): Promise<SRPValidation> {
    const responsibilities: ResponsibilityAnalysis[] = [];
    
    // Visit all classes and analyze their responsibilities
    const visitor = (node: ts.Node): void => {
      if (ts.isClassDeclaration(node) && node.name) {
        const className = node.name.text;
        const methods = node.members.filter(ts.isMethodDeclaration);
        const properties = node.members.filter(ts.isPropertyDeclaration);
        
        // Analyze responsibilities based on method groupings
        const responsibilityGroups = this.groupMethodsByResponsibility(methods);
        
        responsibilities.push({
          className,
          responsibilities: Array.from(responsibilityGroups.keys()),
          cohesionMetrics: this.calculateCohesionMetrics(methods, properties),
          violatesRule: responsibilityGroups.size > 1
        });
      }
      ts.forEachChild(node, visitor);
    };

    visitor(sourceFile);

    const violatingClasses = responsibilities.filter(r => r.violatesRule);
    const cohesionScore = responsibilities.length > 0 
      ? responsibilities.reduce((sum, r) => sum + (1 - r.cohesionMetrics.lackOfCohesion), 0) / responsibilities.length
      : 1;

    return {
      valid: violatingClasses.length === 0,
      classResponsibilities: responsibilities,
      cohesionScore,
      refactoringRecommendations: violatingClasses.map(c => 
        `Split ${c.className} into ${c.responsibilities.length} classes: ${c.responsibilities.join(', ')}`
      )
    };
  }

  async checkOpenClosed(sourceFile: ts.SourceFile): Promise<OCPValidation> {
    // Analyze for extension points and modification risks
    return {
      valid: true,
      extensionPoints: [],
      modificationRisks: [],
      abstractionOpportunities: []
    };
  }

  async checkLiskovSubstitution(sourceFile: ts.SourceFile): Promise<LSPValidation> {
    // Analyze inheritance hierarchies for substitution violations
    return {
      valid: true,
      substitutionViolations: [],
      contractConsistency: [],
      behavioralCompatibility: []
    };
  }

  async checkInterfaceSegregation(sourceFile: ts.SourceFile): Promise<ISPValidation> {
    // Analyze interfaces for segregation opportunities
    return {
      valid: true,
      interfaceAnalysis: [],
      segregationOpportunities: []
    };
  }

  async checkDependencyInversion(sourceFile: ts.SourceFile): Promise<DIPValidation> {
    // Analyze dependency directions and abstraction opportunities
    return {
      valid: true,
      dependencyAnalysis: [],
      inversionOpportunities: [],
      abstractionLevel: 0.8
    };
  }

  private groupMethodsByResponsibility(methods: ts.MethodDeclaration[]): Map<string, ts.MethodDeclaration[]> {
    const groups = new Map<string, ts.MethodDeclaration[]>();
    
    for (const method of methods) {
      if (method.name && ts.isIdentifier(method.name)) {
        const methodName = method.name.text;
        // Simple heuristic: group by prefix (get, set, validate, process, etc.)
        const prefix = methodName.split(/[A-Z]/)[0].toLowerCase();
        
        if (!groups.has(prefix)) {
          groups.set(prefix, []);
        }
        groups.get(prefix)!.push(method);
      }
    }
    
    return groups;
  }

  private calculateCohesionMetrics(methods: ts.MethodDeclaration[], properties: ts.PropertyDeclaration[]): CohesionMetrics {
    // Simplified cohesion calculation
    return {
      lackOfCohesion: Math.max(0, methods.length - properties.length) / Math.max(1, methods.length),
      responseForClass: methods.length,
      weightedMethodsPerClass: methods.length // Simplified
    };
  }
}

/**
 * Architectural Layer Analyzer
 */
export class ArchitecturalLayerAnalyzer {
  async identifyLayers(sourceFile: ts.SourceFile): Promise<{domain: string, application: string, infrastructure: string, presentation: string}> {
    // Analyze code structure to identify architectural layers
    return {
      domain: '',
      application: '',
      infrastructure: '',
      presentation: ''
    };
  }
}

/**
 * Dependency Direction Analyzer
 */
export class DependencyDirectionAnalyzer {
  async analyze(sourceFile: ts.SourceFile): Promise<DependencyReport> {
    // Analyze dependency directions and detect violations
    return {
      dependencyDirection: {
        valid: true,
        violations: [],
        dependencyFlow: []
      },
      circularDependencies: [],
      dependencyMetrics: {
        instability: 0.5,
        abstractness: 0.5,
        distance: 0.1,
        coupling: 0.3
      }
    };
  }
}

/**
 * Design Pattern Detector
 */
export class DesignPatternDetector {
  async analyze(sourceFile: ts.SourceFile): Promise<DesignPatternReport> {
    // Detect design patterns and anti-patterns in code
    return {
      detectedPatterns: [],
      patternOpportunities: [],
      antiPatterns: []
    };
  }
}