#!/usr/bin/env node
/**
 * Relay 长轮询客户端
 *
 * 独立进程运行，从中央 Relay 拉取属于本租户的加密事件，
 * 用本地 RSA 私钥解密后落盘到 outputs/webhook/。
 *
 * 启动方式：
 *   node scripts/start-relay-client.js [device-guid]
 *   npm run relay
 */

const crypto = require('crypto');
const { saveWebhookEvent } = require('../mcp/src/core/webhook-server');
const {
  getRelayBaseUrl,
  getTenantApiSecret,
  getRelayPrivateKey,
  getTenantId,
  getRelayDeviceGuid
} = require('../mcp/src/core/relay-config');

const POLL_WAIT_MS = 30000;
const INITIAL_BACKOFF_MS = 1000;
const MAX_BACKOFF_MS = 60000;

function saveEvent(eventId, payload) {
  const filePath = saveWebhookEvent({ eventId, ...payload }, 'relay');
  return filePath;
}

function decryptPayload(encryptedPayload, privateKeyPem) {
  const key = crypto.createPrivateKey(privateKeyPem);
  const buffer = Buffer.from(encryptedPayload, 'base64');
  const decrypted = crypto.privateDecrypt({ key, oaepHash: 'sha256' }, buffer);
  return decrypted.toString('utf8');
}

async function ackEvents(baseUrl, apiSecret, guid, eventIds) {
  if (!eventIds.length) return;
  try {
    const res = await fetch(`${baseUrl}/api/relay/ack`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Bearer ${apiSecret}`
      },
      body: JSON.stringify({ guid, eventIds })
    });

    if (!res.ok) {
      console.warn('[RelayClient] ACK 失败:', res.status, await res.text());
      return;
    }

    const data = await res.json();
    console.log(`[RelayClient] ACK ${data.ackedCount || eventIds.length} 条事件`);
  } catch (err) {
    console.warn('[RelayClient] ACK 请求异常:', err.message);
  }
}

async function runPollOnce(baseUrl, apiSecret, guid, privateKey) {
  const res = await fetch(`${baseUrl}/api/relay/poll`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      Authorization: `Bearer ${apiSecret}`
    },
    body: JSON.stringify({ guid, batchSize: 100, waitMs: POLL_WAIT_MS })
  });

  if (!res.ok) {
    throw new Error(`poll failed: ${res.status} ${await res.text()}`);
  }

  const data = await res.json();
  if (!data.events || !data.events.length) return;

  console.log(`[RelayClient] 取回 ${data.events.length} 条事件`);
  const eventIds = [];

  for (const event of data.events) {
    try {
      const decrypted = decryptPayload(event.encryptedPayload, privateKey);
      const payload = JSON.parse(decrypted);
      const filePath = saveEvent(event.eventId, payload);
      console.log(`[RelayClient] 已解密落盘: ${filePath}`);
      eventIds.push(event.eventId);
    } catch (err) {
      console.error(`[RelayClient] 解密/落盘失败 eventId=${event.eventId}:`, err.message);
      // 解密失败也要 ACK，避免 Relay 重复投递
      eventIds.push(event.eventId);
    }
  }

  await ackEvents(baseUrl, apiSecret, guid, eventIds);
}

async function main() {
  const baseUrl = getRelayBaseUrl();
  const apiSecret = getTenantApiSecret();
  const privateKey = getRelayPrivateKey();
  const tenantId = getTenantId();

  // guid 优先级：命令行参数 > 环境变量 > relay-config.json
  const guid = process.argv[2] || process.env.RELAY_DEVICE_GUID || getRelayDeviceGuid();

  if (!apiSecret || !privateKey || !tenantId) {
    console.error('[RelayClient] 缺少配置：请检查 .env.local 中的 TENANT_API_SECRET、RELAY_PRIVATE_KEY、TENANT_ID');
    process.exit(1);
  }
  if (!guid) {
    console.error('[RelayClient] 缺少 deviceGuid：请通过命令行传入，或配置 RELAY_DEVICE_GUID / relay-config.json');
    process.exit(1);
  }

  console.log(`[RelayClient] 启动 Relay 轮询: ${baseUrl}`);
  console.log(`[RelayClient] tenantId=${tenantId}, guid=${guid}`);

  let backoff = INITIAL_BACKOFF_MS;

  while (true) {
    try {
      await runPollOnce(baseUrl, apiSecret, guid, privateKey);
      backoff = INITIAL_BACKOFF_MS;
    } catch (err) {
      console.error('[RelayClient] 轮询异常:', err.message);
      console.log(`[RelayClient] ${backoff}ms 后重试...`);
      await new Promise((resolve) => setTimeout(resolve, backoff));
      backoff = Math.min(backoff * 2, MAX_BACKOFF_MS);
    }
  }
}

main().catch((err) => {
  console.error('[RelayClient] 致命错误:', err);
  process.exit(1);
});