#!/usr/bin/env node
/**
 * SubagentStart Hook: 子 Agent 路由上下文注入 (v5.2 Neural Gateway)
 *
 * 将父级路由信息注入子 Agent 上下文，
 * 确保子 Agent 感知当前路由决策。
 *
 * stdin: { session_id, hook_event_name: "SubagentStart" }
 * stdout: JSON { hookSpecificOutput: { additionalContext } }
 * 退出码: 始终 0
 */

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

const readStdin = require('./lib/read-stdin.js');
const STATE_EXPIRY_MS = 5 * 60 * 1000; // 5 分钟过期


const CLAUDE_ROOT = require('./lib/root.js');
const DEBUG_DIR = path.join(CLAUDE_ROOT, 'debug');
const STATE_FILE = path.join(DEBUG_DIR, 'route-state-current.json');

/**
 * 加载路由状态 (含过期检查)
 * @returns {Object|null}
 */
function loadRouteState() {
  try {
    if (!fs.existsSync(STATE_FILE)) return null;
    const state = JSON.parse(fs.readFileSync(STATE_FILE, 'utf8'));

    // 过期检查
    if (state.ts) {
      const tsMs = new Date(state.ts).getTime();
      if (isNaN(tsMs)) return null;
      const age = Date.now() - tsMs;
      if (age > STATE_EXPIRY_MS) return null;
    }

    return state;
  } catch {
    return null;
  }
}

// === 主流程 ===
function main() {
  readStdin({ maxSize: 128 * 1024 }).then(input => {
    // 读取路由状态
    const state = loadRouteState();

    if (!state) {
      // 无状态或已过期 → 静默放行
      process.exit(0);
      return;
    }

    const primary = state.routing?.primary || 'developer-expert';
    const confidence = state.routing?.confidence || 0;
    const complexity = state.intent?.complexity || 'medium';
    const intents = (state.intent?.intents || []).join(',');
    const chain = (state.routing?.chain || []).join(' → ');

    let ctx = `[BWR 子Agent上下文] 父级路由: ${primary}, 置信度: ${(confidence * 100).toFixed(0)}%`;
    ctx += `, 复杂度: ${complexity}, 意图: ${intents}`;
    if (chain) {
      ctx += `, 技能链: ${chain}`;
    }


    // --- v6.6: Context Anchors Lite + 重读纪律 ---
    // 安全设计: 只注入路径提示, Agent 自行用 Read 工具获取 (经过 block-sensitive-reads)
    try {
      const anchorsFile = path.join(CLAUDE_ROOT, "context-anchors.json");
      if (fs.existsSync(anchorsFile)) {
        const anchors = JSON.parse(fs.readFileSync(anchorsFile, "utf8"));
        const files = (anchors.files || []).slice(0, 10);
        if (files.length > 0) {
          ctx += String.fromCharCode(10)+"[CONTEXT_ANCHOR] 上下文锚点文件 (请用 Read 工具重读): " + files.join(", ");
        }
      }
    } catch {}
    ctx += String.fromCharCode(10)+"[重读纪律] 你是 fresh 实例。不要假设之前的 Agent 做了什么，从当前代码状态独立判断。";

    const output = {
      hookSpecificOutput: {
        hookEventName: 'SubagentStart',
        additionalContext: ctx,
      },
    };

    process.stdout.write(JSON.stringify(output));
    process.exit(0);
  }).catch(() => process.exit(0));
}

// 模块导出 (供测试)
if (typeof module !== 'undefined') {
  module.exports = { loadRouteState, CLAUDE_ROOT: require("./lib/root.js") };
}

if (require.main === module) {
  main();
}