import * as fs from 'fs';
import * as path from 'path';
import { detectPatterns, getSeverityCounts, DetectionResult } from './detectors.js';

export interface FileResult {
  file: string;
  lines: number;
  detection: DetectionResult;
  trustScore: number; // 0-100, higher = more trustworthy
}

export interface AnalysisConfig {
  include: string[];
  exclude: string[];
  maxSize: number; // max file size in bytes
  minScore: number; // minimum trust score threshold
}

export interface AnalysisSummary {
  totalFiles: number;
  scannedFiles: number;
  totalLines: number;
  issuesFound: number;
  criticalIssues: number;
  highIssues: number;
  mediumIssues: number;
  lowIssues: number;
  averageTrustScore: number;
  filesWithIssues: number;
  cleanFiles: number;
  riskLevel: 'low' | 'medium' | 'high' | 'critical';
  fileResults: FileResult[];
}

const DEFAULT_CONFIG: AnalysisConfig = {
  include: ['.js', '.ts', '.jsx', '.tsx', '.py', '.java', '.go', '.rb', '.php', '.cs', '.cpp', '.c', '.swift', '.kt', '.rs'],
  exclude: ['node_modules', 'dist', '.git', 'vendor', 'build', 'coverage', '.next', 'out', '__pycache__', '.venv', 'venv'],
  maxSize: 1024 * 1024, // 1MB
  minScore: 50
};

function shouldScan(filePath: string, config: AnalysisConfig): boolean {
  const ext = path.extname(filePath).toLowerCase();
  if (!config.include.includes(ext)) return false;
  
  const parts = filePath.split(path.sep);
  for (const ex of config.exclude) {
    if (parts.some(part => part === ex)) return false;
  }
  
  return true;
}

function calculateTrustScore(detection: DetectionResult, lines: number): number {
  const counts = getSeverityCounts(detection.patterns);
  
  // Base score: 100
  let score = 100;
  
  // Deduct for each severity level
  score -= counts.critical * 25;
  score -= counts.high * 15;
  score -= counts.medium * 8;
  score -= counts.low * 2;
  
  // Deduct for AI pattern density (patterns per 100 lines)
  const density = (detection.patterns.length / Math.max(lines, 1)) * 100;
  score -= Math.min(density * 3, 30); // cap at 30 points
  
  // Boost for very clean files
  if (detection.patterns.length === 0) {
    score += 5; // bonus for clean file
  }
  
  // Clamp to 0-100
  return Math.max(0, Math.min(100, Math.round(score)));
}

function analyzeFile(filePath: string, basePath: string): FileResult | null {
  try {
    const stat = fs.statSync(filePath);
    if (stat.size > DEFAULT_CONFIG.maxSize) {
      return null; // skip large files
    }
    
    const content = fs.readFileSync(filePath, 'utf-8');
    const lines = content.split('\n').length;
    const detection = detectPatterns(content);
    const trustScore = calculateTrustScore(detection, lines);
    
    return {
      file: path.relative(basePath, filePath),
      lines,
      detection,
      trustScore
    };
  } catch (err) {
    return null; // skip unreadable files
  }
}

export function analyzeDirectory(dirPath: string, config: Partial<AnalysisConfig> = {}): AnalysisSummary {
  const fullConfig = { ...DEFAULT_CONFIG, ...config };
  const results: FileResult[] = [];
  let totalFiles = 0;
  let totalLines = 0;
  
  function scanDir(dir: string) {
    const entries = fs.readdirSync(dir, { withFileTypes: true });
    
    for (const entry of entries) {
      const fullPath = path.join(dir, entry.name);
      
      if (entry.isDirectory()) {
        let skip = false;
        for (const ex of fullConfig.exclude) {
          if (entry.name === ex) {
            skip = true;
            break;
          }
        }
        if (!skip) {
          scanDir(fullPath);
        }
      } else if (entry.isFile()) {
        totalFiles++;
        if (shouldScan(fullPath, fullConfig)) {
          const result = analyzeFile(fullPath, dirPath);
          if (result) {
            results.push(result);
            totalLines += result.lines;
          }
        }
      }
    }
  }
  
  scanDir(dirPath);
  
  // Calculate summary
  let issuesFound = 0;
  let criticalIssues = 0;
  let highIssues = 0;
  let mediumIssues = 0;
  let lowIssues = 0;
  let filesWithIssues = 0;
  let totalTrustScore = 0;
  
  for (const result of results) {
    const counts = getSeverityCounts(result.detection.patterns);
    issuesFound += result.detection.patterns.length;
    criticalIssues += counts.critical || 0;
    highIssues += counts.high || 0;
    mediumIssues += counts.medium || 0;
    lowIssues += counts.low || 0;
    
    if (result.detection.patterns.length > 0) {
      filesWithIssues++;
    }
    totalTrustScore += result.trustScore;
  }
  
  const averageTrustScore = results.length > 0 ? Math.round(totalTrustScore / results.length) : 100;
  
  // Determine risk level
  let riskLevel: 'low' | 'medium' | 'high' | 'critical' = 'low';
  if (criticalIssues > 0) {
    riskLevel = 'critical';
  } else if (highIssues > 0 || averageTrustScore < 50) {
    riskLevel = 'high';
  } else if (mediumIssues > 0 || averageTrustScore < 70) {
    riskLevel = 'medium';
  }
  
  return {
    totalFiles,
    scannedFiles: results.length,
    totalLines,
    issuesFound,
    criticalIssues,
    highIssues,
    mediumIssues,
    lowIssues,
    averageTrustScore,
    filesWithIssues,
    cleanFiles: results.length - filesWithIssues,
    riskLevel,
    fileResults: results.sort((a, b) => a.trustScore - b.trustScore) // sort by trust score ascending
  };
}

export function analyzeFileContent(filePath: string, content?: string): FileResult | null {
  try {
    const actualContent = content || fs.readFileSync(filePath, 'utf-8');
    const lines = actualContent.split('\n').length;
    const detection = detectPatterns(actualContent);
    const trustScore = calculateTrustScore(detection, lines);
    
    return {
      file: path.basename(filePath),
      lines,
      detection,
      trustScore
    };
  } catch (err) {
    return null;
  }
}