private-reserve-auction-dapp/
├── package.json
├── next.config.mjs
├── postcss.config.mjs
├── lib/
│   ├── isomorphic-ws-fix.mjs
│   ├── midnight.ts                 # session, patched provider, hex helpers
│   ├── auction.ts                  # deploy, circuits, decode state
│   ├── address.ts                  # Bech32 → UserAddress bytes
│   └── secret.ts                   # crypto.getRandomValues + localStorage
├── app/
│   ├── globals.css
│   ├── layout.tsx
│   ├── page.tsx                    # landing page
│   └── auction/
│       ├── page.tsx                # server shell
│       └── AuctionClient.tsx       # seller + bidder UI
├── contract/
│   ├── package.json
│   └── src/
│       ├── private-reserve-auction.compact
│       ├── index.ts                # CompiledContract.withVacantWitnesses
│       └── managed/private-reserve-auction/  # compiler output (gitignored)
├── scripts/
│   └── sync-zk-assets.mjs          # → public/zk/private-reserve-auction/
└── public/zk/private-reserve-auction/        # keys + zkir (gitignored until sync)

node --version   # 20+
docker --version # optional local devnet tests

curl --proto '=https' --tlsv1.2 -sSf \
  https://github.com/midnightntwrk/compact/releases/latest/download/compact-installer.sh | sh
source $HOME/.local/bin/env

{
  "name": "private-reserve-auction-dapp",
  "version": "0.1.0",
  "private": true,
  "type": "module",
  "scripts": {
    "dev": "next dev",
    "build": "npm run sync:assets && next build",
    "compact": "npm run compact --prefix contract",
    "sync:assets": "node scripts/sync-zk-assets.mjs",
    "postinstall": "echo 'All deps at root level'"
  },
  "dependencies": {
    "@midnight-ntwrk/compact-js": "^2.5.0",
    "@midnight-ntwrk/compact-runtime": "0.16.0",
    "@midnight-ntwrk/ledger-v8": "8.0.3",
    "@midnight-ntwrk/midnight-js-contracts": "4.0.4",
    "@midnight-ntwrk/midnight-js-fetch-zk-config-provider": "4.0.4",
    "@midnight-ntwrk/midnight-js-indexer-public-data-provider": "4.0.4",
    "@midnight-ntwrk/midnight-js-network-id": "4.0.4",
    "@midnight-ntwrk/midnight-js-types": "4.0.4",
    "@midnight-ntwrk/wallet-sdk-address-format": "3.1.0",
    "@tailwindcss/postcss": "^4.3.2",
    "next": "^15.0.0",
    "postcss": "^8.5.16",
    "react": "^19.0.0",
    "react-dom": "^19.0.0",
    "tailwindcss": "^4.3.2"
  },
  "devDependencies": {
    "@types/node": "^22.0.0",
    "@types/react": "^19.0.0",
    "@types/react-dom": "^19.0.0",
    "typescript": "^5.7.0"
  }
}

{
  "name": "@private-reserve-auction/contract",
  "version": "0.1.0",
  "private": true,
  "type": "module",
  "scripts": {
    "compact": "compact compile src/private-reserve-auction.compact src/managed/private-reserve-auction"
  },
  "devDependencies": {
    "@midnight-ntwrk/compact-runtime": "0.16.0"
  }
}

npm run compact

Expected circuits: `bid`, `closeAuction`, `revealPrice`, `claimItem`, `claimProceeds`.

---

pragma language_version 0.23;
import CompactStandardLibrary;

export enum AuctionState {
    OPEN,
    CLOSED,
    SETTLED
}

export sealed ledger organizer: Bytes<32>;
export sealed ledger hiddenPrice: Bytes<32>;
export sealed ledger maxBids: Uint<16>;
export ledger publicPrice: Uint<32>;
export ledger auctionState: AuctionState;
export ledger bidders: Map<Bytes<32>, Uint<32>>;
export ledger bidCount: Counter;
export ledger highestBid: Uint<32>;
export ledger winnerClaimed: Set<UserAddress>;

constructor(minPrice: Uint<32>, maxBidCount: Uint<16>, _secret: Bytes<32>) {
    assert(minPrice > 0, "Reserve price must be greater than zero");
    assert(maxBidCount > 0, "Max bids must be greater than zero");

    const pubKey = getDappPublicKey(_secret);
    organizer = disclose(pubKey);

    hiddenPrice = commitPrice(minPrice as Bytes<32>, _secret);
    maxBids = disclose(maxBidCount);
    publicPrice = 0;
    highestBid = 0;
    auctionState = AuctionState.OPEN;
}

export circuit bid(bidAmount: Uint<32>, _address: UserAddress, _secret: Bytes<32>): [] {
    assert(auctionState == AuctionState.OPEN, "Auction is not open");
    assert(bidCount < maxBids, "Bids are full");
    assert(bidAmount > 0, "Bid must be greater than zero");

    const pubKey = getDappPublicKey(_secret);
    assert(pubKey != organizer, "Organizer cannot bid");

    const bidderId = disclose(pubKey);
    const publicBid = disclose(bidAmount);

    if (bidders.member(bidderId)) {
        assert(bidders.lookup(bidderId) < publicBid, "New bid must be higher");
    }

    bidders.insert(bidderId, publicBid);
    bidCount.increment(1);

    if (publicBid > highestBid) {
        highestBid = publicBid;
    }

    if (bidCount == maxBids) {
        auctionState = AuctionState.CLOSED;
    }
}

export circuit closeAuction(_secret: Bytes<32>): [] {
    const pubKey = getDappPublicKey(_secret);
    assert(organizer == pubKey, "Only organizer can close");
    assert(auctionState == AuctionState.OPEN, "Auction already closed");

    auctionState = AuctionState.CLOSED;
}

export circuit revealPrice(minPrice: Uint<32>, _secret: Bytes<32>): [] {
    const pubKey = getDappPublicKey(_secret);
    assert(organizer == pubKey, "Only organizer can reveal");
    assert(auctionState == AuctionState.CLOSED, "Auction not closed");

    const hashedPrice = commitPrice(minPrice as Bytes<32>, _secret);
    assert(hashedPrice == hiddenPrice, "Price mismatch — cannot change reserve");

    publicPrice = disclose(minPrice);
    auctionState = AuctionState.SETTLED;
}

export circuit claimItem(_address: UserAddress, _secret: Bytes<32>): [] {
    assert(auctionState == AuctionState.SETTLED, "Auction not settled");
    assert(highestBid >= publicPrice, "No valid winning bid");
    assert(!winnerClaimed.member(disclose(_address)), "Already claimed");

    const pubKey = getDappPublicKey(_secret);
    const bidderId = disclose(pubKey);
    assert(bidders.lookup(bidderId) == highestBid, "Not the highest bidder");

    // Privacy boundary: winner pays reserve, identity revealed
    receiveUnshielded(nativeToken(), publicPrice as Uint<128>);
    winnerClaimed.insert(disclose(_address));
}

export circuit claimProceeds(_address: UserAddress, _secret: Bytes<32>): [] {
    const pubKey = getDappPublicKey(_secret);
    assert(organizer == pubKey, "Not organizer");
    assert(auctionState == AuctionState.SETTLED, "Auction not settled");
    assert(winnerClaimed.size() > 0, "No winner claimed");

    sendUnshielded(
        nativeToken(),
        publicPrice as Uint<128>,
        right<ContractAddress, UserAddress>(disclose(_address))
    );
}

circuit commitPrice(_price: Bytes<32>, _secret: Bytes<32>): Bytes<32> {
    return persistentCommit<Bytes<32>>(_price, _secret);
}

circuit getDappPublicKey(_secret: Bytes<32>): Bytes<32> {
    return persistentHash<Vector<2, Bytes<32>>>([pad(32, "private-auction:pk:"), _secret]);
}

import { CompiledContract } from '@midnight-ntwrk/compact-js';
import { sampleSigningKey, ContractState } from '@midnight-ntwrk/compact-runtime';

let _contractModule: any = null;
let _compiledContract: any = null;
let _ledgerFn: any = null;

export async function getCompiledContract(zkPath?: string): Promise<any> {
  if (!_compiledContract) {
    if (!_contractModule) {
      _contractModule = await import('./managed/private-reserve-auction/contract/index.js');
    }
    _compiledContract = CompiledContract.make(
      'private-reserve-auction',
      _contractModule.Contract,
    );
    _compiledContract = CompiledContract.withVacantWitnesses(_compiledContract);
  }
  return _compiledContract;
}

export async function getLedger(): Promise<any> {
  if (!_ledgerFn) {
    if (!_contractModule) {
      _contractModule = await import('./managed/private-reserve-auction/contract/index.js');
    }
    _ledgerFn = _contractModule.ledger;
  }
  return _ledgerFn;
}

export { sampleSigningKey, ContractState };

import { MidnightBech32m, UnshieldedAddress } from '@midnight-ntwrk/wallet-sdk-address-format';

export function bech32ToUserAddress(bech32: string, networkId: string): { bytes: Uint8Array } {
  const parsed = MidnightBech32m.parse(bech32).decode(UnshieldedAddress, networkId);
  return { bytes: new Uint8Array(parsed.data) };
}

import { fromHex, toHex } from './midnight';

export function generateSecret(): Uint8Array {
  const bytes = new Uint8Array(32);
  crypto.getRandomValues(bytes);
  return bytes;
}

export function saveSecret(
  role: 'seller' | 'bidder',
  contractAddress: string,
  secret: Uint8Array,
) {
  localStorage.setItem(`private-auction:${role}:${contractAddress}`, toHex(secret));
}

export function loadSecret(
  role: 'seller' | 'bidder',
  contractAddress: string,
): Uint8Array | null {
  const hex = localStorage.getItem(`private-auction:${role}:${contractAddress}`);
  return hex ? fromHex(hex) : null;
}

import { setNetworkId } from '@midnight-ntwrk/midnight-js-network-id';
import { indexerPublicDataProvider } from '@midnight-ntwrk/midnight-js-indexer-public-data-provider';
import { FetchZkConfigProvider } from '@midnight-ntwrk/midnight-js-fetch-zk-config-provider';
import { ContractState } from '@midnight-ntwrk/compact-runtime';
import type { MidnightProvider, WalletProvider } from '@midnight-ntwrk/midnight-js-types';

export type ConnectedSession = {
  api: any;
  config: any;
  providers: {
    privateStateProvider: ReturnType<typeof createPrivateStateProvider>;
    publicDataProvider: ReturnType<typeof createPatchedPublicDataProvider>;
    zkConfigProvider: FetchZkConfigProvider<any>;
    proofProvider: { proveTx: (unprovenTx: any) => Promise<any> };
    walletProvider: WalletProvider;
    midnightProvider: MidnightProvider;
  };
  unshieldedAddress: string;
  coinPublicKeyBytes: Uint8Array;
};

export function fromHex(hex: string): Uint8Array {
  const h = hex.startsWith('0x') ? hex.slice(2) : hex;
  return Uint8Array.from(h.match(/.{1,2}/g)!.map((b) => parseInt(b, 16)));
}

export function toHex(bytes: Uint8Array): string {
  return Array.from(bytes)
    .map((b) => b.toString(16).padStart(2, '0'))
    .join('');
}

function coinPublicKeyToBytes(pk: unknown): Uint8Array {
  if (pk instanceof Uint8Array) return pk.length === 32 ? pk : pk.slice(0, 32);
  if (typeof pk === 'string') {
    const hex = pk.startsWith('0x') ? pk.slice(2) : pk;
    if (hex.length === 64 && /^[0-9a-fA-F]+$/.test(hex)) return fromHex(hex);
    return new Uint8Array(32);
  }
  if (Array.isArray(pk)) {
    return new Uint8Array(pk.length >= 32 ? pk.slice(0, 32) : [...pk, ...new Uint8Array(32 - pk.length)]);
  }
  if (pk && typeof pk === 'object' && 'bytes' in (pk as object)) {
    return coinPublicKeyToBytes((pk as { bytes: unknown }).bytes);
  }
  return new Uint8Array(32);
}

function createPrivateStateProvider() {
  let scope = '';
  const stateStore = new Map<string, unknown>();
  const signingKeyStore = new Map<string, unknown>();
  const key = (id: string) => `${scope}:${id}`;
  return {
    setContractAddress(address: string) {
      scope = address;
    },
    async set(id: string, state: unknown) {
      stateStore.set(key(id), state);
    },
    async get(id: string) {
      return stateStore.get(key(id)) ?? null;
    },
    async remove(id: string) {
      stateStore.delete(key(id));
    },
    async clear() {
      stateStore.clear();
    },
    async setSigningKey(addr: string, k: unknown) {
      signingKeyStore.set(addr, k);
    },
    async getSigningKey(addr: string) {
      return signingKeyStore.get(addr) ?? null;
    },
    async removeSigningKey(addr: string) {
      signingKeyStore.delete(addr);
    },
    async clearSigningKeys() {
      signingKeyStore.clear();
    },
    async exportPrivateStates(): Promise<never> {
      throw new Error('Not implemented.');
    },
    async importPrivateStates(): Promise<never> {
      throw new Error('Not implemented.');
    },
    async exportSigningKeys(): Promise<never> {
      throw new Error('Not implemented.');
    },
    async importSigningKeys(): Promise<never> {
      throw new Error('Not implemented.');
    },
  };
}

function createPatchedPublicDataProvider(queryUrl: string, subscriptionUrl: string) {
  const base = indexerPublicDataProvider(queryUrl, subscriptionUrl);
  return {
    ...base,
    async queryContractState(contractAddress: string, config?: unknown) {
      if (config) return base.queryContractState(contractAddress, config as never);
      const res = await fetch(queryUrl, {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({
          query: `query LATEST_CONTRACT_STATE($address: HexEncoded!) {
            contractAction(address: $address) { state }
          }`,
          variables: { address: contractAddress },
        }),
      });
      if (!res.ok) throw new Error(`Indexer HTTP error: ${res.status}`);
      const payload = await res.json();
      if (payload.errors?.length) {
        throw new Error(payload.errors.map((e: { message: string }) => e.message).join('; '));
      }
      const action = payload.data?.contractAction ?? null;
      return action ? ContractState.deserialize(fromHex(action.state)) : null;
    },
  };
}

export async function createConnectedSession(
  api: any,
  zkAssetBasePath: string,
): Promise<ConnectedSession> {
  const [config, unshieldedAddress, shieldedAddress] = await Promise.all([
    api.getConfiguration(),
    api.getUnshieldedAddress(),
    api.getShieldedAddresses(),
  ]);

  setNetworkId(config.networkId);

  const zkConfigProvider = new FetchZkConfigProvider(
    new URL(zkAssetBasePath, window.location.origin).toString(),
    window.fetch.bind(window),
  );
  const provingProvider = await api.getProvingProvider(zkConfigProvider);

  const proofProvider = {
    async proveTx(unprovenTx: any) {
      const { CostModel } = await import('@midnight-ntwrk/ledger-v8');
      return unprovenTx.prove(provingProvider, CostModel.initialCostModel());
    },
  };

  const walletProvider: WalletProvider = {
    getCoinPublicKey: () => shieldedAddress.shieldedCoinPublicKey,
    getEncryptionPublicKey: () => shieldedAddress.shieldedEncryptionPublicKey,
    balanceTx: async (tx: any) => {
      const txHex = toHex(tx.serialize());
      const balanced = await api.balanceUnsealedTransaction(txHex);
      if (!balanced?.tx) throw new Error('balanceUnsealedTransaction returned invalid result');
      const { Transaction } = await import('@midnight-ntwrk/ledger-v8');
      return Transaction.deserialize('signature', 'proof', 'binding', fromHex(balanced.tx));
    },
  };

  const midnightProvider: MidnightProvider = {
    submitTx: async (tx: any) => {
      const txHex = toHex(tx.serialize());
      const result = await api.submitTransaction(txHex);
      if (typeof result === 'string' && result) return result;
      if (result?.transactionId) return result.transactionId;
      if (result?.id) return result.id;
      return txHex.slice(0, 64);
    },
  };

  return {
    api,
    config,
    providers: {
      privateStateProvider: createPrivateStateProvider(),
      publicDataProvider: createPatchedPublicDataProvider(config.indexerUri, config.indexerWsUri),
      zkConfigProvider,
      proofProvider,
      walletProvider,
      midnightProvider,
    },
    unshieldedAddress: unshieldedAddress.unshieldedAddress,
    coinPublicKeyBytes: coinPublicKeyToBytes(shieldedAddress.shieldedCoinPublicKey),
  };
}

export async function pollForState(
  queryUrl: string,
  contractAddress: string,
  maxAttempts = 120,
  intervalMs = 2000,
): Promise<string> {
  for (let i = 0; i < maxAttempts; i++) {
    const res = await fetch(queryUrl, {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify({
        query: `query LATEST_CONTRACT_STATE($address: HexEncoded!) {
          contractAction(address: $address) { state }
        }`,
        variables: { address: contractAddress },
      }),
    });
    if (res.ok) {
      const payload = await res.json();
      const state = payload.data?.contractAction?.state;
      if (state) return state;
    }
    await new Promise((r) => setTimeout(r, intervalMs));
  }
  throw new Error(`Contract state not indexed after ${(maxAttempts * intervalMs) / 1000}s`);
}

export async function detectWallet(): Promise<any> {
  const w =
    (window as any).midnight?.['1am'] ??
    Object.values((window as any).midnight ?? {})[0];
  if (!w) throw new Error('No Midnight wallet extension found');
  return w;
}