监听 USDT / USDC 收款

import { createPublicClient, http, pad, type Hex } from "viem";

const apiKey = process.env.BLOCKVECTRA_API_KEY;
if (!apiKey) {
  throw new Error("请设置环境变量 BLOCKVECTRA_API_KEY");
}

const CHAIN = "bsc_mainnet";
const RPC_URL = "https://api.blockvectra.com/v1/bsc_mainnet";
const CHAINS_URL = "https://api.blockvectra.com/v1/chains";

// 目标稳定币合约地址（此处以 BSC USDT 为例）
const TOKEN_CONTRACT = "0x55d398326f99059fF775485246999027B3197955" as const;
const TOKEN_DECIMALS = 18;

// 监听的专属收款地址
const RECIPIENT_ADDRESS = "0xdded13D555B6DA811103cC1794D3d4330F69632C" as const;

// Transfer(address,address,uint256) 签名哈希
const TRANSFER_TOPIC0 = "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef" as const;

// 将 20 字节地址左补零至 32 字节
const paddedRecipient = pad(RECIPIENT_ADDRESS.toLowerCase() as Hex, { size: 32 });

// 防范区块重组的安全确认深度（区块数）
const CONFIRMATION_DEPTH = 15n;

// 1. 从公开元数据接口读取目标链的能力配置（免鉴权、不计费）
const chainsRes = await fetch(CHAINS_URL);
const { chains } = (await chainsRes.json()) as {
  chains: Array<{
    chain: string;
    ws: boolean;
    subscriptions: string[];
    max_logs_block_range: number;
  }>;
};

const chainConfig = chains.find((c) => c.chain === CHAIN);
if (!chainConfig) {
  throw new Error(`未在 /v1/chains 中找到链 ${CHAIN}`);
}

const maxLogsRange = BigInt(chainConfig.max_logs_block_range || 1000);
console.log(`链: ${CHAIN} | WebSocket 支持: ${chainConfig.ws} | 单次日志跨度上限: ${maxLogsRange}`);

// 2. 初始化 viem 客户端
const client = createPublicClient({
  transport: http(RPC_URL, {
    fetchOptions: {
      headers: { "x-api-key": apiKey },
    },
  }),
});

// 本地去重集合，以 (transactionHash, logIndex) 为复合主键
const processedLogs = new Set<string>();

// 3. 计算查询区间：从当前链头扣除确认深度得到 safeHead
const currentHead = await client.getBlockNumber();
const safeHead = currentHead - CONFIRMATION_DEPTH;

// 演示：从 safeHead 前 10 个区块作为游标起点
let cursor = safeHead > 10n ? safeHead - 10n : 0n;

console.log(`当前链头: ${currentHead} | 安全链头: ${safeHead} | 轮询起始游标: ${cursor}`);

while (cursor <= safeHead) {
  const chunkEnd = cursor + maxLogsRange - 1n < safeHead ? cursor + maxLogsRange - 1n : safeHead;

  const logs = await client.getLogs({
    address: TOKEN_CONTRACT,
    fromBlock: cursor,
    toBlock: chunkEnd,
    topics: [
      TRANSFER_TOPIC0,
      null, // 匹配任意发送方
      paddedRecipient, // 匹配目标收款地址
    ],
  });

  for (const log of logs) {
    // 忽略因重组被撤回的日志
    if (log.removed) continue;

    const dedupKey = `${log.transactionHash}-${log.logIndex}`;
    if (processedLogs.has(dedupKey)) {
      continue;
    }
    processedLogs.add(dedupKey);

    // 解析 uint256 转账金额
    const rawAmount = BigInt(log.data);
    const divisor = 10n ** BigInt(TOKEN_DECIMALS);
    const integerPart = rawAmount / divisor;
    const fractionalPart = rawAmount % divisor;

    console.log(
      `[收款到账] 金额: ${integerPart}.${fractionalPart} | ` +
      `交易: ${log.transactionHash} | 索引: ${log.logIndex} | 区块: ${log.blockNumber}`
    );
  }

  cursor = chunkEnd + 1n;
}

// 运行方式：npx tsx example.mts