export interface EncodeTxParams {
  /** Transaction type name, e.g. 'TransferV2Tx' */
  type: string;
  /** Transaction data — same shape as client.encodeXxxTx({ tx }) */
  tx: {
    itx: any;
    from?: string;
    pk?: string;
    nonce?: number;
    chainId?: string;
    signature?: Uint8Array | Buffer;
    signatures?: any[];
    signaturesList?: any[];
    delegator?: string;
  };
  /** Wallet { address, publicKey|pk } */
  wallet: { address: string; publicKey?: string; pk?: string };
  /** Delegator address */
  delegator?: string;
  /** Chain ID (from getChainInfo) */
  chainId?: string;
  /** Fee config [{ typeUrl, fee }] (from getForgeState) */
  feeConfig?: Array<{ typeUrl: string; fee: string }>;
}

export interface EncodeTxResult {
  object: Record<string, any>;
  buffer: Buffer;
}

export interface ChainContext {
  chainId: string;
  txFee: Array<{ typeUrl: string; fee: string }>;
}

export type TxEncoder = (params: {
  type: string;
  data: any;
  wallet: any;
  chainHost: string;
}) => Promise<Buffer>;

/**
 * Encode a transaction to protobuf binary.
 * Pure function — no network IO.
 */
export function encodeTx(params: EncodeTxParams): EncodeTxResult;

/**
 * Create a TxEncoder compatible with WalletAuthenticator.txEncoder.
 * Automatically fetches and caches chain context per endpoint.
 */
export function createTxEncoder(): TxEncoder;

/**
 * Fetch minimal chain context (chainId + fee config) from an endpoint.
 * Results are cached — call clearContextCache() to invalidate.
 */
export function fetchContext(chainHost: string): Promise<ChainContext>;

/** Clear the context cache. */
export function clearContextCache(): void;