// Runtime ESM loader for StellaOps Scanner runtime evidence
// Usage: node --experimental-loader=./runtime-esm-loader.mjs app.mjs

import fs from 'fs';
import path from 'path';
import crypto from 'crypto';
import { fileURLToPath, pathToFileURL } from 'url';

const outPath = process.env.SCANNER_NODE_RUNTIME_OUT || path.join(process.cwd(), 'node-runtime-evidence.ndjson');
const root = process.env.SCANNER_NODE_ROOT || process.cwd();
const loaderId = hashLoaderId(import.meta.url);

function hashLoaderId(value) {
  return crypto.createHash('sha256').update(value || '').digest('hex');
}

function scrub(p) {
  if (!p) return p;
  try {
    const absolute = p.startsWith('file:') ? fileURLToPath(p) : p;
    const rel = path.relative(root, absolute);
    return rel.startsWith('..') ? p : rel.split(path.sep).join('/');
  } catch {
    return p;
  }
}

function emit(record) {
  try {
    fs.appendFileSync(outPath, JSON.stringify(record) + '\n');
  } catch {
    // best-effort: ignore write failures
  }
}

export async function resolve(specifier, context, next) {
  const parent = context.parentURL ? scrub(context.parentURL) : undefined;
  const target = scrub(specifier);

  emit({
    type: 'edge',
    from: parent,
    to: target,
    reason: 'runtime-import',
    loaderId
  });

  return next(specifier, context, next);
}

export async function load(url, context, next) {
  const pathOrUrl = scrub(url);
  emit({
    type: 'component',
    path: pathOrUrl,
    reason: 'runtime-load',
    loaderId
  });

  return next(url, context, next);
}