import { ApiPromise } from "@polkadot/api";
import { Header, BlockHash } from "@polkadot/types/interfaces";
import { ExtrinsicData } from "../types";
/**
 * @category BTC Bridge
 */
export interface SystemAPI {
    /**
     * @returns The current block number being processed.
     */
    getCurrentBlockNumber(): Promise<number>;
    /**
     * @returns The current active block number being processed.
     */
    getCurrentActiveBlockNumber(atBlock?: BlockHash): Promise<number>;
    /**
     * On every new parachain block, call the callback function with the new block header
     * @param callback Function to be called with every new block header
     */
    subscribeToFinalizedBlockHeads(callback: (blockHeader: Header) => void): Promise<() => void>;
    /**
     * On every new parachain block, call the callback function with the new block header
     * @param callback Function to be called with every new unfinalized block header
     */
    subscribeToCurrentBlockHeads(callback: (blockHeader: Header) => void): Promise<() => void>;
    /**
     * @remarks Upgrades runtime using `sudoUncheckedWeight`
     * @param code Hex-encoded wasm blob
     * @returns {ExtrinsicData} A submittable extrinsic and an event that is emitted when extrinsic is submitted.
     */
    setCode(code: string): ExtrinsicData;
    /**
     * @param blockNumber The block number to get the hash for
     * @returns The block hash for the given block number
     */
    getBlockHash(blockNumber: number): Promise<BlockHash>;
    /**
     * Get number of block that will added in amount of seconds from now.
     *
     * @note Based on approximate block time of 12 seconds.
     * @param api Polkadot ApiPromise object.
     * @param secondsFromNow Amount of seconds in the future.
     * @returns Number of block added in future.
     */
    getFutureBlockNumber(secondsFromNow: number): Promise<number>;
}
export declare class DefaultSystemAPI implements SystemAPI {
    private api;
    constructor(api: ApiPromise);
    getCurrentBlockNumber(): Promise<number>;
    getCurrentActiveBlockNumber(atBlock?: BlockHash): Promise<number>;
    subscribeToFinalizedBlockHeads(callback: (blockHeader: Header) => void): Promise<() => void>;
    subscribeToCurrentBlockHeads(callback: (blockHeader: Header) => void): Promise<() => void>;
    setCode(code: string): ExtrinsicData;
    getBlockHash(blockNumber: number): Promise<BlockHash>;
    getFutureBlockNumber(secondsFromNow: number): Promise<number>;
}