/**
 * session-once.js — 会话级执行去重 (P0-2)
 * 依赖 session-start-restore.js 维护的 .session-restored 文件获取 session_id
 * 标志文件: session-state/.session-once.json  { hookName: sessionId }
 * 原子写: tmp+rename 防多窗口竞态
 */
'use strict';
const fs = require('fs');
const path = require('path');

let CLAUDE_ROOT;
try { CLAUDE_ROOT = require('./root.js'); } catch { CLAUDE_ROOT = path.resolve(__dirname, '..', '..'); }

const STATE_DIR = path.join(CLAUDE_ROOT, 'session-state');
const FLAGS_PATH = path.join(STATE_DIR, '.session-once.json');
const SESSION_FILE = path.join(STATE_DIR, '.session-restored');

function getCurrentSessionId() {
  try { return fs.readFileSync(SESSION_FILE, 'utf8').trim() || ''; }
  catch { return ''; }
}

function loadFlags() {
  try { return JSON.parse(fs.readFileSync(FLAGS_PATH, 'utf8')) || {}; }
  catch { return {}; }
}

function saveFlags(flags) {
  try {
    if (!fs.existsSync(STATE_DIR)) fs.mkdirSync(STATE_DIR, { recursive: true });
    const tmp = FLAGS_PATH + '.tmp.' + process.pid;
    fs.writeFileSync(tmp, JSON.stringify(flags), 'utf8');
    fs.renameSync(tmp, FLAGS_PATH);
  } catch {}
}

function hasRun(hookName) {
  const sid = getCurrentSessionId();
  if (!sid) return false;
  return loadFlags()[hookName] === sid;
}

function markRun(hookName) {
  const sid = getCurrentSessionId();
  if (!sid) return;
  const flags = loadFlags();
  flags[hookName] = sid;
  saveFlags(flags);
}

module.exports = { hasRun, markRun, getCurrentSessionId };