// tools/path-normalization.mjs
/**
 * Path normalization — router-gate v4 spec §3.1.1.
 * + glob-matcher util (used by skill-scope-verifier, tdd-real-test-verifier).
 * Pure-core; I/O (realpath) injected via opts for testability.
 */
import path from 'node:path';
import os from 'node:os';
import fs from 'node:fs';

const ENV_WHITELIST = ['HOME', 'USERPROFILE', 'APPDATA', 'XDG_CONFIG_HOME', 'XDG_DATA_HOME', 'XDG_CACHE_HOME'];

export function expandHome(target, homedir) {
  if (target === '~') return homedir;
  if (target.startsWith('~/') || target.startsWith('~\\')) {
    return homedir + target.slice(1);
  }
  return target;
}

export function expandEnvVars(target, env) {
  let out = target;
  for (const name of ENV_WHITELIST) {
    const val = env[name];
    if (val === undefined) continue;
    out = out.split(`%${name}%`).join(val);
    out = out.split(`\${${name}}`).join(val);
    // bare $VAR — only when followed by non-word boundary
    out = out.replace(new RegExp(`\\$${name}(?![A-Za-z0-9_])`, 'g'), val);
  }
  return out;
}

export function caseFold(p, platform) {
  return platform === 'win32' ? p.toLowerCase() : p;
}

export function globToRegExp(pattern) {
  let re = '';
  for (let i = 0; i < pattern.length; i++) {
    const c = pattern[i];
    if (c === '*') {
      if (pattern[i + 1] === '*') {
        re += '.*';            // ** — across separators
        i++;
        if (pattern[i + 1] === '/') i++; // consume trailing slash of **/
      } else {
        re += '[^/]*';          // * — within segment
      }
    } else if (c === '?') {
      re += '[^/]';
    } else if ('.+^${}()|[]\\'.includes(c)) {
      re += '\\' + c;
    } else {
      re += c;
    }
  }
  return new RegExp(`^${re}$`);
}

export function globMatch(pathStr, pattern) {
  const norm = (s) => s.split('\\').join('/');
  return globToRegExp(norm(pattern)).test(norm(pathStr));
}

export function pathNormalize(target, opts = {}) {
  const {
    homedir = os.homedir(),
    env = process.env,
    platform = process.platform,
    realpath = fs.realpathSync,
    resolve = path.resolve,
  } = opts;
  let p = expandHome(target, homedir);
  p = expandEnvVars(p, env);
  const resolved = resolve(p);
  let real;
  try {
    real = realpath(resolved);
  } catch {
    real = resolved; // ENOENT — best-effort resolved path
  }
  return caseFold(real, platform);
}