/**
* USDs Stablecoin Client
*
* Provides interactions with Sperax USDs on Arbitrum.
*/
import {
createPublicClient,
createWalletClient,
http,
formatUnits,
parseUnits,
type PublicClient,
type WalletClient,
type Account,
} from "viem";
import { arbitrum } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";
/**
* USDs contract address on Arbitrum
*/
export const USDS_ADDRESS =
"0xD74f5255D557944cf7Dd0E45FF521520002D5748" as const;
/**
* Collateral vault address
*/
export const VAULT_ADDRESS =
"0x6Bbc476Ee35CBA9e9c3A59fc5b10d7a0BC6f74Ca" as const;
/**
* USDs ABI for read operations
*/
const USDS_ABI = [
{
inputs: [{ name: "account", type: "address" }],
name: "balanceOf",
outputs: [{ name: "", type: "uint256" }],
stateMutability: "view",
type: "function",
},
{
inputs: [],
name: "totalSupply",
outputs: [{ name: "", type: "uint256" }],
stateMutability: "view",
type: "function",
},
{
inputs: [],
name: "rebasingCreditsPerToken",
outputs: [{ name: "", type: "uint256" }],
stateMutability: "view",
type: "function",
},
{
inputs: [{ name: "account", type: "address" }],
name: "creditsBalanceOf",
outputs: [
{ name: "", type: "uint256" },
{ name: "", type: "uint256" },
],
stateMutability: "view",
type: "function",
},
{
inputs: [
{ name: "to", type: "address" },
{ name: "amount", type: "uint256" },
],
name: "transfer",
outputs: [{ name: "", type: "bool" }],
stateMutability: "nonpayable",
type: "function",
},
{
inputs: [
{ name: "spender", type: "address" },
{ name: "amount", type: "uint256" },
],
name: "approve",
outputs: [{ name: "", type: "bool" }],
stateMutability: "nonpayable",
type: "function",
},
] as const;
/**
* USDs Client Configuration
*/
export interface USDsClientConfig {
privateKey?: `0x${string}`;
rpcUrl?: string;
}
/**
* Client for interacting with Sperax USDs stablecoin
*/
export class USDsClient {
private publicClient: PublicClient;
private walletClient?: WalletClient;
private account?: Account;
constructor(config: USDsClientConfig = {}) {
const transport = http(config.rpcUrl);
this.publicClient = createPublicClient({
chain: arbitrum,
transport,
});
if (config.privateKey) {
this.account = privateKeyToAccount(config.privateKey);
this.walletClient = createWalletClient({
chain: arbitrum,
transport,
account: this.account,
});
}
}
/**
* Get USDs balance for an address
*/
async getBalance(address: `0x${string}`): Promise<string> {
const balance = await this.publicClient.readContract({
address: USDS_ADDRESS,
abi: USDS_ABI,
functionName: "balanceOf",
args: [address],
});
return formatUnits(balance as bigint, 18);
}
/**
* Get total USDs supply
*/
async getTotalSupply(): Promise<string> {
const supply = await this.publicClient.readContract({
address: USDS_ADDRESS,
abi: USDS_ABI,
functionName: "totalSupply",
});
return formatUnits(supply as bigint, 18);
}
/**
* Get rebasing credits per token (used for yield calculation)
*/
async getRebasingCreditsPerToken(): Promise<bigint> {
const credits = await this.publicClient.readContract({
address: USDS_ADDRESS,
abi: USDS_ABI,
functionName: "rebasingCreditsPerToken",
});
return credits as bigint;
}
/**
* Get credits balance for yield tracking
*/
async getCreditsBalance(
address: `0x${string}`
): Promise<{ credits: bigint; creditsPerToken: bigint }> {
const [credits, creditsPerToken] = (await this.publicClient.readContract({
address: USDS_ADDRESS,
abi: USDS_ABI,
functionName: "creditsBalanceOf",
args: [address],
})) as [bigint, bigint];
return { credits, creditsPerToken };
}
/**
* Transfer USDs to another address
*/
async transfer(
to: `0x${string}`,
amount: string
): Promise<`0x${string}`> {
if (!this.walletClient || !this.account) {
throw new Error("Wallet not initialized. Provide privateKey in config.");
}
const amountWei = parseUnits(amount, 18);
const hash = await this.walletClient.writeContract({
address: USDS_ADDRESS,
abi: USDS_ABI,
functionName: "transfer",
args: [to, amountWei],
account: this.account,
chain: arbitrum,
});
return hash;
}
/**
* Approve USDs spending
*/
async approve(
spender: `0x${string}`,
amount: string
): Promise<`0x${string}`> {
if (!this.walletClient || !this.account) {
throw new Error("Wallet not initialized. Provide privateKey in config.");
}
const amountWei = parseUnits(amount, 18);
const hash = await this.walletClient.writeContract({
address: USDS_ADDRESS,
abi: USDS_ABI,
functionName: "approve",
args: [spender, amountWei],
account: this.account,
chain: arbitrum,
});
return hash;
}
/**
* Get the public client for advanced operations
*/
getPublicClient(): PublicClient {
return this.publicClient;
}
/**
* Get the wallet client for advanced operations
*/
getWalletClient(): WalletClient | undefined {
return this.walletClient;
}
}
