#!/usr/bin/env node
/**
 * token-saver-bash-limiter.js · TSE Layer 3 · 2026-04-27
 * PreToolUse (Bash) · 查看型命令自动截断输出
 * 仅截断 cat/find/tree/journalctl 等查看命令, 不动 build/git/ssh 执行命令
 * 行为: fail-open, 通过 updatedInput 追加 | head -N
 */
'use strict';

const readStdin = require('./lib/read-stdin.js');

const VIEW_RE = [
  /\bcat\s+\S+/, /\bdocker\s+logs\b/, /\bjournalctl\b/,
  /\bdmesg\b/, /\bps\s+aux/, /\bfind\s+\//,
  /\bls\s+-[^\s]*R/, /\btree\b/, /\bsqlite3\b.*\.dump/,
  /\bnpm\s+ls\b/, /\bpip\s+(list|freeze)\b/,
  /\bdpkg\s+-l/, /\bsystemctl\s+list/,
];
const SKIP_RE = [
  /\|\s*head\b/, /\|\s*tail\b/, /\|\s*grep\b/,
  /\|\s*awk\b/, /\|\s*sed\b/, /\|\s*wc\b/,
  /[>]/, /\bgit\s+(push|pull|fetch|clone|rebase|merge|commit)/,
  /\bnpm\s+(install|run|build|test)/, /\bpnpm\s/,
  /\bdocker\s+(build|run|push|compose)/, /\bssh\b/, /\bscp\b/,
  /\bcurl\b/, /\bwget\b/, /\bmake\b/, /\bcargo\b/, /\bgo\s+(build|run|test)/,
];

(async () => {
  try {
    const hookData = await readStdin();
    if (hookData.tool_name !== 'Bash') process.exit(0);
    const cmd = (hookData.tool_input || {}).command || '';
    if (!cmd || cmd.length < 5) process.exit(0);

    for (const re of SKIP_RE) { if (re.test(cmd)) process.exit(0); }

    let match = false;
    for (const re of VIEW_RE) { if (re.test(cmd)) { match = true; break; } }
    if (!match) process.exit(0);

    const limit = /\bfind\s+\/|journalctl|tree\s+\/|\.dump/.test(cmd) ? 80 : 150;
    const newCmd = cmd + ' 2>&1 | head -' + limit;

    process.stdout.write(JSON.stringify({
      continue: true,
      hookSpecificOutput: {
        hookEventName: 'PreToolUse',
        updatedInput: { command: newCmd, description: (hookData.tool_input || {}).description },
        additionalContext: '[TSE·BASH_LIMITER] 输出已截断至 ' + limit + ' 行。需完整输出请 > file 重定向。'
      }
    }));
    process.exit(0);
  } catch { process.exit(0); }
})();