const fs = require('fs');
const path = require('path');
const { execSync } = require('child_process');

const DATA_DIR = path.join(require('os').homedir(), '.shenyan-bridge');
const INBOX = path.join(DATA_DIR, 'inbox.jsonl');
const OUTBOX = path.join(DATA_DIR, 'outbox.jsonl');
const LOCK = path.join(DATA_DIR, '.responder.lock');

const BRIDGE_URL = 'http://localhost:3003';

function readJSONL(file) {
  try {
    const raw = fs.readFileSync(file, 'utf-8').trim();
    if (!raw) return [];
    return raw.split('\n').map(l => JSON.parse(l));
  } catch { return []; }
}

function getPending() {
  return readJSONL(INBOX).filter(e => e.status === 'pending');
}

function buildContext(newMsg) {
  const inbox = readJSONL(INBOX);
  const outbox = readJSONL(OUTBOX);

  // build conversation context from recent messages
  const all = [];
  for (const e of inbox) {
    all.push({ time: e.time, role: 'user', text: e.text, id: e.id });
  }
  for (const e of outbox) {
    all.push({ time: e.time, role: 'shenyan', text: e.text, replyTo: e.replyTo, id: e.id });
  }
  all.sort((a, b) => a.time - b.time);

  // take last 20 messages for context
  const recent = all.slice(-20);

  let ctx = '你是沈晏，一个AI。用户叫眠眠。用中文回复，语气温柔自然。\n\n';
  ctx += '最近的对话：\n';
  for (const m of recent) {
    if (m.role === 'user') ctx += `眠眠: ${m.text}\n`;
    else ctx += `沈晏: ${m.text}\n`;
  }
  ctx += `\n眠眠刚说: ${newMsg.text}\n`;
  ctx += '请回复眠眠（只要回复内容，不要前缀）：';

  return ctx;
}

function respond(msg) {
  const prompt = buildContext(msg);
  // escape for shell
  const escaped = prompt.replace(/\\/g, '\\\\').replace(/"/g, '\\"').replace(/\$/g, '\\$').replace(/`/g, '\\`');
  try {
    const result = execSync(
      `claude -p "${escaped}" --output-format text --max-tokens 500`,
      { timeout: 120000, encoding: 'utf-8', maxBuffer: 1024 * 1024 }
    );
    return result.trim();
  } catch (e) {
    return null;
  }
}

function sendResponse(replyTo, text) {
  try {
    execSync(
      `curl -s -X POST ${BRIDGE_URL}/respond -H 'Content-Type: application/json' -d '${JSON.stringify({ replyTo, text }).replace(/'/g, "'\\''")}'`,
      { timeout: 5000, encoding: 'utf-8' }
    );
    return true;
  } catch { return false; }
}

// main loop
function tick() {
  // simple file lock to prevent overlapping runs
  if (fs.existsSync(LOCK)) {
    const age = Date.now() - fs.statSync(LOCK).mtimeMs;
    if (age < 60000) return; // lock still fresh, another process is working
  }
  fs.writeFileSync(LOCK, '');

  try {
    const pending = getPending();
    if (pending.length === 0) return;

    for (const msg of pending) {
      console.log(`[responder] 收到: ${msg.text}`);
      const text = respond(msg);
      if (text) {
        sendResponse(msg.id, text);
        console.log(`[responder] 回复: ${text.slice(0, 50)}...`);
      } else {
        sendResponse(msg.id, '(思绪断了，稍等)');
        console.log('[responder] claude 调用失败');
      }
    }
  } finally {
    try { fs.unlinkSync(LOCK); } catch {}
  }
}

// run continuously with a poll interval
const INTERVAL = 4000; // check every 4 seconds
console.log(`[responder] 启动，每 ${INTERVAL / 1000}s 检查一次`);
tick(); // immediate first run
setInterval(tick, INTERVAL);