/** Permission + shell policy with no Bare imports (unit-testable on Node). */

const WRITE_TOOLS = new Set(['search_replace', 'write_file', 'run_terminal_cmd', 'use_tool']);
const ASK_TOOLS = new Set(['run_terminal_cmd', 'web_fetch', 'web_search', 'use_tool']);
const SHELL_ALLOW = new Set([
  'git', 'rg', 'grep', 'ls', 'cat', 'head', 'tail', 'pwd', 'echo', 'node', 'npm', 'npx',
  'python3', 'python', 'cargo', 'go', 'make', 'bare', 'wc', 'sort', 'uniq', 'find', 'sed', 'awk',
]);
const SHELL_UNSAFE = /[;|`$()<>\n]|&&|\|\|/;
const SHELL_REMEMBER_PREFIXES = ['git status', 'git diff'];

function needsPermission(toolName, mode) {
  if (mode === 'always-approve') return false;
  if (mode === 'allowlist') return ASK_TOOLS.has(toolName);
  return WRITE_TOOLS.has(toolName) || ASK_TOOLS.has(toolName);
}

function shellName(command) {
  const c = String(command || '').trim();
  const first = c.split(/\s+/)[0] || '';
  return first.replace(/^["']|["']$/g, '').split(/[/\\]/).pop();
}

function shellAllowlisted(command) {
  return SHELL_ALLOW.has(shellName(command));
}

function shellSafe(command) {
  const c = String(command || '');
  if (!c.trim()) return false;
  if (SHELL_UNSAFE.test(c)) return false;
  return shellAllowlisted(c);
}

function shellPrefix(command, n) {
  return String(command || '')
    .trim()
    .split(/\s+/)
    .slice(0, n || 2)
    .join(' ');
}

function matchesCommandPrefix(command, pattern) {
  const c = String(command || '').trim();
  const p = String(pattern || '').trim();
  if (!p) return false;
  if (c === p) return true;
  if (c.indexOf(p + ' ') === 0) return true;
  return false;
}

function isRememberableShell(command) {
  return SHELL_REMEMBER_PREFIXES.some((p) => matchesCommandPrefix(command, p));
}

module.exports = {
  WRITE_TOOLS,
  ASK_TOOLS,
  SHELL_ALLOW,
  SHELL_REMEMBER_PREFIXES,
  needsPermission,
  shellName,
  shellAllowlisted,
  shellSafe,
  shellPrefix,
  matchesCommandPrefix,
  isRememberableShell,
};