// Copyright 2017-2021 @polkadot/api-derive authors & contributors
// SPDX-License-Identifier: Apache-2.0

import type { ApiInterfaceRx } from '@polkadot/api/types';
import type { AccountId, AccountIndex } from '@polkadot/types/interfaces';
import type { Observable } from '@polkadot/x-rxjs';
import type { AccountIndexes } from '../types';

import { map } from '@polkadot/x-rxjs/operators';

import { memo } from '../util';

/**
 * @name idToIndex
 * @param {( AccountId | string )} accountId - An accounts Id in different formats.
 * @returns Returns the corresponding AccountIndex.
 * @example
 * <BR>
 *
 * ```javascript
 * const ALICE = '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY';
 * api.derive.accounts.idToIndex(ALICE, (accountIndex) => {
 *   console.log(`The AccountIndex of ${ALICE} is ${accountIndex}`);
 * });
 * ```
 */
export function idToIndex (instanceId: string, api: ApiInterfaceRx): (accountId: AccountId | string) => Observable<AccountIndex | undefined> {
  return memo(instanceId, (accountId: AccountId | string): Observable<AccountIndex | undefined> =>
    api.derive.accounts.indexes().pipe(
      map((indexes: AccountIndexes): AccountIndex | undefined =>
        (indexes || {})[accountId.toString()]
      )
    ));
}