#!/usr/bin/env node
// tools/scripts/lint-game-logic-purity.mjs
// Source: 04-CONTEXT.md D-25 — purity guard for packages/game-logic.
// Greps for forbidden APIs in src/**/*.ts. Comments are stripped before scan.
//
// Usage: node tools/scripts/lint-game-logic-purity.mjs
// Exit: 0 clean, 1 forbidden API found, 2 usage error.

import { readFileSync, readdirSync, statSync } from 'node:fs';
import { join } from 'node:path';

const ROOT = 'packages/game-logic/src';

const FORBIDDEN = [
  { name: 'Date.*', re: /\bDate\s*\./ },
  { name: 'new Date(', re: /\bnew\s+Date\s*\(/ },
  { name: 'Math.random', re: /\bMath\s*\.\s*random\b/ },
  { name: 'process.*', re: /\bprocess\s*\.[a-z]/i },
  { name: 'fs.*', re: /(?:^|\W)fs\s*\./ },
  { name: 'fetch(', re: /\bfetch\s*\(/ },
  { name: "require('http", re: /require\s*\(\s*['"]https?\b/ },
  { name: "import 'http", re: /from\s*['"]https?\b/ },
  { name: "import 'node:fs'", re: /from\s*['"]node:fs\b/ },
  { name: "import 'node:os'", re: /from\s*['"]node:os\b/ },
];

/** Strip block and line comments. Cheap, not a full parser; sufficient.
 * Normalises CRLF → LF before splitting so that the `$` anchor in the
 * line-comment regex correctly matches the end of each line on Windows
 * checkouts (without normalisation a trailing \r defeats the pattern). */
function stripComments(src) {
  return src
    .replace(/\r\n/g, '\n')
    .replace(/\/\*[\s\S]*?\*\//g, '')
    .split('\n')
    .map((line) => line.replace(/\/\/.*$/, ''))
    .join('\n');
}

function walk(dir, out = []) {
  for (const f of readdirSync(dir)) {
    const p = join(dir, f);
    const s = statSync(p);
    if (s.isDirectory()) walk(p, out);
    else if (p.endsWith('.ts')) out.push(p);
  }
  return out;
}

const files = walk(ROOT);
let violations = 0;
for (const f of files) {
  const src = stripComments(readFileSync(f, 'utf-8'));
  for (const rule of FORBIDDEN) {
    if (rule.re.test(src)) {
      process.stderr.write(`lint-game-logic-purity: ${f} contains forbidden API ${rule.name}\n`);
      violations++;
    }
  }
}

if (violations > 0) {
  process.stderr.write(
    `lint-game-logic-purity: ${violations} violation(s) in ${files.length} file(s).\n`,
  );
  process.exit(1);
}

console.log(`lint-game-logic-purity: OK (${files.length} file(s) clean)`);
process.exit(0);