#!/usr/bin/env node
// [PATCH-X03-SESSION-ISOLATION]
/**
 * PostToolUse Hook: 会话心跳检测器 (session-isolated)
 * Matcher: Edit|Write|Skill|Agent|Bash|mcp__.*
 *
 * 按 session_id 隔离计数, 多窗口不互相干扰.
 * 阈值策略同原版: 20(INFO) / 30(WARNING) / 40(CRITICAL) / 50+ 每10次强提醒
 * 退出码: 始终 0 (纯通知, 不阻断工作流)
 */
'use strict';

const fs = require('fs');
const path = require('path');

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

const STATE_FILE = path.join(CLAUDE_ROOT, 'debug', 'session-heartbeat.json');
const SESSION_TIMEOUT_MS = 30 * 60 * 1000;

const THRESHOLDS = [
  { count: 20, level: 'INFO',     msg: '当前会话已执行 {n} 次工具调用。如对话较长，可考虑 /clear 释放上下文。' },
  { count: 30, level: 'WARNING',  msg: '当前会话已执行 {n} 次工具调用，上下文可能接近饱和。建议在合适时机 /clear 重置上下文窗口。' },
  { count: 40, level: 'CRITICAL', msg: '当前会话已执行 {n} 次工具调用，上下文压力较大。强烈建议用户 /clear 重置。如有重要任务进行中，可委托 Agent 子进程隔离执行。' },
];

(async () => {
  try {
    let hookData = {};
    try { hookData = await readStdin(); } catch {}

    const sid = hookData.session_id || 'default';
    const debugDir = path.join(CLAUDE_ROOT, 'debug');
    if (!fs.existsSync(debugDir)) fs.mkdirSync(debugDir, { recursive: true });

    let allState = {};
    try {
      if (fs.existsSync(STATE_FILE)) {
        allState = JSON.parse(fs.readFileSync(STATE_FILE, 'utf8'));
      }
    } catch { allState = {}; }

    // 清理 2 小时无活动的其他会话 (防文件膨胀)
    const now = Date.now();
    const GC_MS = 2 * 3600 * 1000;
    for (const k of Object.keys(allState)) {
      if (k !== sid && now - (allState[k]?.lastActivity || 0) > GC_MS) delete allState[k];
    }

    let state = allState[sid] || { count: 0, lastActivity: now, notified: [] };

    // 会话超时: 30 分钟无活动 → 重置该会话
    if (now - (state.lastActivity || 0) > SESSION_TIMEOUT_MS) {
      state = { count: 0, lastActivity: now, notified: [] };
    }

    state.count += 1;
    state.lastActivity = now;

    let notification = null;

    for (const t of THRESHOLDS) {
      if (state.count === t.count && !state.notified.includes(t.count)) {
        notification = { level: t.level, msg: t.msg.replace('{n}', state.count) };
        state.notified.push(t.count);
        break;
      }
    }

    if (!notification && state.count >= 50 && state.count % 10 === 0 && !state.notified.includes(state.count)) {
      notification = {
        level: 'CRITICAL',
        msg: `当前会话已执行 ${state.count} 次工具调用，上下文严重饱和。请立即建议用户 /clear 或将剩余任务委托给 Agent 子进程。`
      };
      state.notified.push(state.count);
    }

    allState[sid] = state;
    const _tmpHb = STATE_FILE + '.tmp.' + process.pid; // [PATCH-X08-ATOMIC-WRITE]
    fs.writeFileSync(_tmpHb, JSON.stringify(allState), 'utf8');
    fs.renameSync(_tmpHb, STATE_FILE);

    if (notification) {
      console.log(JSON.stringify({
        continue: true,
        suppressOutput: false,
        systemMessage: `[session-heartbeat ${notification.level}] ${notification.msg}`
      }));
    }
  } catch {
    // Fail-open
  }
  process.exit(0);
})();