/**
 * @packageDocumentation
 * @module harmony-network
 * @hidden
 */

import { RPCRequestPayload } from '../types';
import { RPCMethod } from './rpc';
/**
 * @class JsonRpc
 * @description json rpc instance
 * @return {JsonRpc} Json RPC instance
 */
class JsonRpc {
  messageId: number;
  constructor() {
    /**
     * @var {Number} messageId
     * @memberof JsonRpc.prototype
     * @description message id, default 0
     */
    this.messageId = 0;
  }

  /**
   * @function toPayload
   * @memberof JsonRpc.prototype
   * @description convert method and params to payload object
   * @param  {String} method - RPC method
   * @param  {Array<object>} params - params that send to RPC
   * @return {Object} payload object
   */
  toPayload = (
    method: RPCMethod | string,
    params: string | undefined | any[],
  ): RPCRequestPayload<any> => {
    // FIXME: error to be done by shared/errors
    if (!method) {
      throw new Error('jsonrpc method should be specified!');
    }

    // advance message ID
    this.messageId += 1;

    const sendParams =
      params === undefined ? [] : typeof params === 'string' ? [params] : [...params];

    return {
      jsonrpc: '2.0',
      id: this.messageId,
      method,
      params: sendParams,
    };
  };
}

export { JsonRpc };