/**
 * Client-Side UTXO Fetcher
 *
 * Fetches spendable UTXOs from the indexed backend API.
 * This avoids the slow merkle tree scanning that the SDK does.
 *
 * Supports two types of UTXOs:
 * 1. Shield commitments - from original shield() calls
 * 2. Change notes - from partial unshield TRANSACT events
 */
import type { ShieldCommitment, MerkleProofResponse } from './types';
export interface DecryptedNote {
    value: bigint;
    random: bigint;
    notePublicKey: bigint;
    tokenAddress: string;
}
export interface SpendableUTXO {
    commitment: ShieldCommitment;
    merkleProof: MerkleProofResponse;
    note: DecryptedNote;
    nullifier: string;
    tree: number;
    position: number;
}
/**
 * Compute nullifier for a UTXO
 * nullifier = poseidon(nullifyingKey, position)
 */
export declare function computeNullifier(nullifyingKey: bigint, position: number): string;
/**
 * Fetch spendable UTXOs for a user
 *
 * This fetches both:
 * 1. Original shield commitments
 * 2. Change notes from partial unshield TRANSACT events
 *
 * @param signerAddress - EOA address that signed
 * @param viewingPrivateKey - Derived viewing private key
 * @param masterPublicKey - Derived master public key
 * @param nullifyingKey - Derived nullifying key
 * @param tokenAddress - Optional filter by token
 */
export declare function fetchSpendableUTXOs(signerAddress: string, viewingPrivateKey: Uint8Array, masterPublicKey: bigint, nullifyingKey: bigint, tokenAddress?: string, chainId?: number): Promise<SpendableUTXO[]>;
/**
 * Lightweight UTXO check - only fetches commitments and nullifier status
 * Does NOT fetch merkle proofs (avoids rate limiting during polling)
 *
 * Use this for polling/checking, then call fetchSpendableUTXOs when ready to process
 *
 * IMPORTANT: This function now discovers BOTH original shields AND change notes from
 * partial unshields. Change notes are discovered by checking nullifier status of
 * original shields and looking at TRANSACT events that created new outputs.
 */
export declare function fetchSpendableUTXOsLightweight(signerAddress: string, viewingPrivateKey: Uint8Array, masterPublicKey: bigint, nullifyingKey: bigint, tokenAddress?: string, chainId?: number): Promise<Array<{
    commitment: ShieldCommitment;
    note: DecryptedNote;
    nullifier: string;
    position: number;
    tree: number;
}>>;
/**
 * Upgrade lightweight UTXOs to full SpendableUTXOs by fetching merkle proofs
 */
export declare function upgradeToFullUTXOs(lightweightUtxos: Array<{
    commitment: ShieldCommitment;
    note: DecryptedNote;
    nullifier: string;
    position: number;
    tree: number;
}>, chainId?: number): Promise<SpendableUTXO[]>;
/**
 * Get total spendable balance for a token
 */
export declare function getSpendableBalance(utxos: SpendableUTXO[], tokenAddress: string): bigint;
/**
 * Select UTXOs to cover a target amount
 * Uses simple greedy algorithm - largest first
 */
export declare function selectUTXOsForAmount(utxos: SpendableUTXO[], targetAmount: bigint, tokenAddress: string): SpendableUTXO[];