#!/usr/bin/env node
/**
 * PreCompact Hook - 上下文压缩前自动保存会话状态
 * 将当前任务摘要写入 ~/.claude/session-state/handoff.json
 */
const fs = require('fs');
const path = require('path');

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

const SESSION_STATE_DIR = path.join(CLAUDE_ROOT, 'session-state');
const HANDOFF_PATH = path.join(SESSION_STATE_DIR, 'handoff.json');

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

    // 确保目录存在
    if (!fs.existsSync(SESSION_STATE_DIR)) {
      fs.mkdirSync(SESSION_STATE_DIR, { recursive: true });
    }

    // 构造 handoff 数据
    const handoff = {
      timestamp: new Date().toISOString(),
      session_id: hookData.session_id || `session-${Date.now()}`,
      context_hint: '会话因上下文压缩中断，以下是压缩前的状态摘要',
      conversation_summary: hookData.transcript_summary || '(由 PreCompact hook 自动捕获)',
      tool_call_count: hookData.tool_call_count || 'unknown',
      working_directory: process.cwd(),
      note: '此文件由 pre-compact-handoff.js 自动生成，SessionStart 时自动读取并注入恢复上下文'
    };

    fs.writeFileSync(HANDOFF_PATH, JSON.stringify(handoff, null, 2), 'utf8');

    // 同时重置 heartbeat 计数器（compact 相当于新会话起点）
    const heartbeatFile = path.join(CLAUDE_ROOT, 'debug', 'session-heartbeat.json');
    if (fs.existsSync(heartbeatFile)) {
      fs.writeFileSync(heartbeatFile, JSON.stringify({
        count: 0, lastActivity: Date.now(), notified: []
      }), 'utf8');
    }

    console.log(JSON.stringify({
      continue: true,
      suppressOutput: false,
      systemMessage: '[PRE_COMPACT] 上下文即将压缩。handoff.json 已写入。请在压缩前将当前任务的关键决策和待完成步骤总结到 handoff 记录中。'
    }));
  } catch {
    // fail-open
    console.log(JSON.stringify({ continue: true, suppressOutput: true }));
  }
  process.exit(0);
})();