/**
* Pyth Oracle Service
* Handles fetching price feeds from Pyth Network for Zest Protocol integration
*/
import { HermesClient } from '@pythnetwork/hermes-client';
import { PYTH_HERMES_URL, PYTH_PRICE_FEED_IDS } from '../utils/zest-constants.js';
import axios from 'axios';
export interface PythPriceFeed {
priceFeedBytes: string; // hex encoded for Clarity contracts
prices: {
btc: number;
stx: number;
usdc: number;
};
timestamp: number;
}
export class PythService {
private hermes: HermesClient;
constructor() {
this.hermes = new HermesClient(PYTH_HERMES_URL, {});
}
/**
* Fetches the latest price feeds from Pyth Network
* Returns hex-encoded price feed data suitable for Clarity contract calls
*/
async getPriceFeed(): Promise<PythPriceFeed> {
try {
const priceIds = [
PYTH_PRICE_FEED_IDS.BTC_USD,
PYTH_PRICE_FEED_IDS.STX_USD,
PYTH_PRICE_FEED_IDS.USDC_USD,
];
// Fetch VAA using REST API (most reliable method)
const vaaUrl = `${PYTH_HERMES_URL}/api/latest_vaas?ids[]=${priceIds[0]}`;
const vaaResponse = await axios.get<string[]>(vaaUrl);
if (!vaaResponse.data || vaaResponse.data.length === 0) {
throw new Error('No VAA data returned from Pyth');
}
// Convert base64 VAA to hex for Clarity
const vaaHex = this.base64ToHex(vaaResponse.data[0]);
// Fetch latest price feeds for price values
const priceFeeds = await this.hermes.getLatestPriceUpdates(priceIds);
if (!priceFeeds || !priceFeeds.parsed || priceFeeds.parsed.length < 3) {
throw new Error('Failed to fetch all required price feeds');
}
// Parse prices from Pyth format
const btcPrice = this.parsePrice(priceFeeds.parsed[0]);
const stxPrice = this.parsePrice(priceFeeds.parsed[1]);
const usdcPrice = this.parsePrice(priceFeeds.parsed[2]);
return {
priceFeedBytes: '0x' + vaaHex,
prices: {
btc: btcPrice,
stx: stxPrice,
usdc: usdcPrice,
},
timestamp: Date.now(),
};
} catch (error: any) {
throw new Error(`Failed to fetch Pyth price feed: ${error.message}`);
}
}
/**
* Gets just the BTC price without fetching full feed data
*/
async getBtcPrice(): Promise<number> {
try {
const priceFeeds = await this.hermes.getLatestPriceUpdates([PYTH_PRICE_FEED_IDS.BTC_USD]);
if (!priceFeeds || !priceFeeds.parsed || priceFeeds.parsed.length === 0) {
throw new Error('Failed to fetch BTC price feed');
}
return this.parsePrice(priceFeeds.parsed[0]);
} catch (error: any) {
throw new Error(`Failed to fetch BTC price: ${error.message}`);
}
}
/**
* Gets just the STX price without fetching full feed data
*/
async getStxPrice(): Promise<number> {
try {
const priceFeeds = await this.hermes.getLatestPriceUpdates([PYTH_PRICE_FEED_IDS.STX_USD]);
if (!priceFeeds || !priceFeeds.parsed || priceFeeds.parsed.length === 0) {
throw new Error('Failed to fetch STX price feed');
}
return this.parsePrice(priceFeeds.parsed[0]);
} catch (error: any) {
throw new Error(`Failed to fetch STX price: ${error.message}`);
}
}
/**
* Parses a Pyth price feed into a USD price
*/
private parsePrice(feed: any): number {
if (!feed || !feed.price) {
throw new Error('Invalid price feed structure');
}
// Pyth prices come with an exponent (e.g., price * 10^expo)
// Actual Price = price.price / 10^|expo|
const price = parseFloat(feed.price.price);
const expo = feed.price.expo;
return price * Math.pow(10, expo);
}
/**
* Converts base64 string to hex
*/
private base64ToHex(base64: string): string {
const buffer = Buffer.from(base64, 'base64');
return buffer.toString('hex');
}
/**
* Converts Uint8Array to hex string
*/
private toHexFromBytes(bytes: Uint8Array): string {
return Buffer.from(bytes).toString('hex');
}
}
