/* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*
*  Licensed to Elasticsearch B.V. under one or more contributor
*  license agreements. See the NOTICE file distributed with
*  this work for additional information regarding copyright
*  ownership. Elasticsearch B.V. licenses this file to you under
*  the Apache License, Version 2.0 (the "License"); you may
*  not use this file except in compliance with the License.
*  You may obtain a copy of the License at
*
* 	http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing,
*  software distributed under the License is distributed on an
*  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
*  KIND, either express or implied.  See the License for the
*  specific language governing permissions and limitations
*  under the License.
*/

using System;
using System.Threading;

namespace OpenSearch.Client
{
	public partial interface IOpenSearchClient
	{
		/// <summary>
		/// Helper method that can parallelize a scroll using the sliced scroll feature of OpenSearch, and return the results as an
		/// <see cref="IObservable{T}"/>.
		/// </summary>
		/// <param name="scrollTime">The time to keep the scroll active on the server until we send another scroll request</param>
		/// <param name="numberOfSlices">
		/// The number of slices to chop the scroll into, typically the number of shards but can be higher and using a
		/// custom routing key
		/// </param>
		IObservable<ScrollAllResponse<T>> ScrollAll<T>(Time scrollTime, int numberOfSlices,
			Func<ScrollAllDescriptor<T>, IScrollAllRequest> selector = null, CancellationToken cancellationToken = default(CancellationToken)
		)
			where T : class;

		/// <summary>
		/// Helper method that can parallelize a scroll using the sliced scroll feature of OpenSearch and return the results as an
		/// <see cref="IObservable{T}"/>.
		/// </summary>
		IObservable<ScrollAllResponse<T>> ScrollAll<T>(IScrollAllRequest request, CancellationToken cancellationToken = default(CancellationToken))
			where T : class;
	}

	public partial class OpenSearchClient
	{
		/// <inheritdoc />
		public IObservable<ScrollAllResponse<T>> ScrollAll<T>(Time scrollTime, int numberOfSlices,
			Func<ScrollAllDescriptor<T>, IScrollAllRequest> selector = null, CancellationToken cancellationToken = default(CancellationToken)
		)
			where T : class =>
			ScrollAll<T>(selector.InvokeOrDefault(new ScrollAllDescriptor<T>(scrollTime, numberOfSlices)), cancellationToken);

		/// <inheritdoc />
		public IObservable<ScrollAllResponse<T>> ScrollAll<T>(IScrollAllRequest request,
			CancellationToken cancellationToken = default(CancellationToken)
		)
			where T : class =>
			new ScrollAllObservable<T>(this, request, cancellationToken);
	}
}