interface ChatState {
  processing: boolean;
  buffer: Telegram.Update[];
}

// bot-tools-server.ts - dispatch_task tool

server.tool('dispatch_task', '...',
  { agentName, prompt, priority },
  async ({ agentName, prompt, priority }) => {
    // 1. 驗證 agent 配置存在且啟用
    const agentPath = join(SOUL_DIR, 'agents', `${agentName}.json`);
    const cfg = JSON.parse(await readFile(agentPath, 'utf-8'));
    if (cfg.enabled === false) return error;

    // 2. 載入現有 queue（或建立空）
    let queue = JSON.parse(await readFile(QUEUE_PATH, 'utf-8'));

    // 3. Dedup：跳過已排隊的相同任務
    const isDupe = queue.tasks.some(
      t => t.agentName === agentName && t.prompt === prompt &&
           (t.status === 'pending' || t.status === 'running')
    );
    if (isDupe) return warn("task already queued");

    // 4. 建立 task entry
    const task = {
      id: randomUUID(),
      agentName, prompt,
      status: 'pending',
      priority: Math.max(1, Math.min(10, priority ?? 5)),
      createdAt: new Date().toISOString(),
      startedAt: null, completedAt: null,
      workerId: null, result: null, error: null,
      costUsd: 0, duration: 0,
    };
    queue.tasks.push(task);

    // 5. 原子性寫入 queue
    await atomicWrite(QUEUE_PATH, JSON.stringify(queue, null, 2));

    // 6. 發出 signal file — worker scheduler 會偵測到
    await writeFile(DISPATCH_SIGNAL, new Date().toISOString());

    return success(`Task dispatched: ${taskId.slice(0, 8)}`);
  }
);

// src/agents/worker-scheduler.ts

const DISPATCH_SIGNAL = join(SOUL_DIR, 'agent-tasks', '.dispatch');

export function startWorkerScheduler(): void {
  // ... 其他初始化

  // 每 10 秒 check signal file
  dispatchPollTimer = setInterval(() => {
    checkDispatchSignal().catch(() => {});
  }, 10_000);
}

async function checkDispatchSignal(): Promise<void> {
  try {
    // 檢查 signal file 是否存在
    await stat(DISPATCH_SIGNAL);

    // 存在 → 移除 signal + 立即處理 queue
    try { await unlink(DISPATCH_SIGNAL); } catch { }
    await logger.info('WorkerScheduler', 'Dispatch signal detected, processing queue...');
    await processQueue();  // ← 立即派工
  } catch {
    // No signal file
  }
}

async function atomicWrite(fullPath: string, content: string): Promise<void> {
  const dir = dirname(fullPath);
  await mkdir(dir, { recursive: true });

  // 寫入臨時檔案
  const tmpPath = join(dir, `.tmp-${randomUUID()}`);
  await writeFile(tmpPath, content, 'utf-8');

  // rename 是原子操作 — 不會有部分寫入
  await rename(tmpPath, fullPath);
}

const isDupe = queue.tasks.some(
  t => t.agentName === agentName && t.prompt === prompt &&
       (t.status === 'pending' || t.status === 'running')
);
if (isDupe) {
  return warn("Task already queued for this agent with same prompt");
}

// worker-scheduler.ts 派工邏輯

const pendingTasks = queue.tasks
  .filter(t => t.status === 'pending')
  .sort((a, b) => {
    if (b.priority !== a.priority) return b.priority - a.priority;
    return a.createdAt.localeCompare(b.createdAt);
  });

for (const task of pendingTasks) {
  const workerId = findFreeWorker();
  if (!workerId) break;  // 沒有空閒 worker

  // 預算檢查（每個 agent 有日額度上限）
  if (!(await reserveBudget(task.agentName, ESTIMATED_COST))) {
    continue;  // 預算不足，跳過，試試下一個
  }

  // 派工到獨立 CLI worker
  executeTask(task, workerId);
}

// explorer.ts（背景 agent）
import { enqueueTask } from '../agents/worker-scheduler.js';

// 派工給另一個 agent
const taskId = await enqueueTask(
  'blog-writer',
  '基於以下研究資料撰寫部落格文章...',
  priority = 8
);