import crypto from 'node:crypto';
import fs from 'node:fs';
import path from 'node:path';

function normalizeSlashes(value) {
  return value.replace(/\\/g, '/');
}

function walkFiles(dir) {
  if (!fs.existsSync(dir)) return [];
  const files = [];
  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
    const entryPath = path.join(dir, entry.name);
    if (entry.isDirectory()) files.push(...walkFiles(entryPath));
    else files.push(entryPath);
  }
  return files;
}

export function hashArtifactDirectory(dir) {
  const files = walkFiles(dir)
    .map(filePath => ({
      filePath,
      relativePath: normalizeSlashes(path.relative(dir, filePath)),
    }))
    .sort((left, right) => left.relativePath.localeCompare(right.relativePath, 'en'));

  const hash = crypto.createHash('sha256');
  let totalBytes = 0;
  for (const file of files) {
    const content = fs.readFileSync(file.filePath);
    totalBytes += content.length;
    hash.update(file.relativePath, 'utf8');
    hash.update('\0');
    hash.update(String(content.length), 'utf8');
    hash.update('\0');
    hash.update(content);
    hash.update('\0');
  }

  return {
    sha256: hash.digest('hex'),
    files: files.length,
    totalBytes,
  };
}