// Copyright 2017-2023 @polkadot/api-derive authors & contributors
// SPDX-License-Identifier: Apache-2.0

import type { Observable } from 'rxjs';
import type { SignedBlockExtended } from '../type/types.js';
import type { DeriveApi } from '../types.js';

import { combineLatest, map, of, switchMap } from 'rxjs';

import { createSignedBlockExtended } from '../type/index.js';
import { memo } from '../util/index.js';
import { getAuthorDetails } from './util.js';

/**
 * @name getBlock
 * @param {( Uint8Array | string )} hash - A block hash as U8 array or string.
 * @description Get a specific block (e.g. rpc.chain.getBlock) and extend it with the author
 * @example
 * <BR>
 *
 * ```javascript
 * const { author, block } = await api.derive.chain.getBlock('0x123...456');
 *
 * console.log(`block #${block.header.number} was authored by ${author}`);
 * ```
 */
export function getBlock (instanceId: string, api: DeriveApi): (hash: Uint8Array | string) => Observable<SignedBlockExtended> {
  return memo(instanceId, (blockHash: Uint8Array | string): Observable<SignedBlockExtended> =>
    combineLatest([
      api.rpc.chain.getBlock(blockHash),
      api.queryAt(blockHash)
    ]).pipe(
      switchMap(([signedBlock, queryAt]) =>
        combineLatest([
          of(signedBlock),
          queryAt.system.events(),
          getAuthorDetails(api, signedBlock.block.header, blockHash)
        ])
      ),
      map(([signedBlock, events, [, validators, author]]) =>
        createSignedBlockExtended(events.registry, signedBlock, events, validators, author)
      )
    )
  );
}