type RelayDataType = {
  /** MEV relay endpoint URL */
  readonly relayUrl: string;

  /** Relay's BLS public key (48 bytes) */
  readonly relayPubkey: Uint8Array;

  /** Builder's BLS public key (48 bytes, optional) */
  readonly builderPubkey?: Uint8Array;

  /** Current consensus layer slot */
  readonly slot: SlotType;

  /** Parent block hash (32 bytes) */
  readonly parentHash: HashType;

  /** Validator fee recipient address (20 bytes) */
  readonly proposerFeeRecipient: AddressType;
};

import { MEV_RELAYS } from './primitives/RelayData/index.js';

MEV_RELAYS.FLASHBOTS          // "https://relay.flashbots.net"
MEV_RELAYS.BLOXROUTE_MAX_PROFIT  // "https://bloxroute.max-profit.bloxroute.com"
MEV_RELAYS.BLOXROUTE_REGULATED   // "https://bloxroute.regulated.bloxroute.com"
MEV_RELAYS.EDEN               // "https://relay.edennetwork.io"
MEV_RELAYS.MANIFOLD           // "https://mainnet-relay.securerpc.com"
MEV_RELAYS.ULTRASOUND         // "https://relay.ultrasound.money"
MEV_RELAYS.AGNOSTIC           // "https://agnostic-relay.net"

import * as RelayData from './primitives/RelayData/index.js';
import { MEV_RELAYS } from './primitives/RelayData/index.js';

const relay = RelayData.from({
  relayUrl: MEV_RELAYS.FLASHBOTS,
  relayPubkey: new Uint8Array(48), // relay's BLS pubkey
  slot: 12345n,
  parentHash: new Uint8Array(32),
  proposerFeeRecipient: "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
});

const url = RelayData.getEndpoint(relay, "/eth/v1/builder/header");
// "https://relay.flashbots.net/eth/v1/builder/header"

const endpoint = RelayData.getEndpoint(relay, "/eth/v1/builder/header");
const params = `${relay.slot}/${relay.parentHash}/${relay.proposerFeeRecipient}`;

const response = await fetch(`${endpoint}/${params}`);
const bid = await response.json();

Builder                    Relay                      Proposer
   |                         |                            |
   |--[submit block bid]---->|                            |
   |                         |--[header+bid]------------->|
   |                         |                            |
   |                         |<--[signed header]----------|
   |                         |                            |
   |<--[request payload]-----|                            |
   |--[block payload]------->|                            |
   |                         |--[full block]------------->|

// Use multiple relays for redundancy
const relays = [
  RelayData.from({ relayUrl: MEV_RELAYS.FLASHBOTS, ... }),
  RelayData.from({ relayUrl: MEV_RELAYS.ULTRASOUND, ... }),
  RelayData.from({ relayUrl: MEV_RELAYS.AGNOSTIC, ... }),
];