/* 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;

namespace OpenSearch.Net
{
	public class DateTimeProvider : IDateTimeProvider
	{
		public static readonly DateTimeProvider Default = new DateTimeProvider();
		private static readonly TimeSpan DefaultTimeout = TimeSpan.FromSeconds(60);
		private static readonly TimeSpan MaximumTimeout = TimeSpan.FromMinutes(30);

		public virtual DateTime DeadTime(int attempts, TimeSpan? timeoutFactor, TimeSpan? maxDeadTimeout)
		{
			var timeout = timeoutFactor.GetValueOrDefault(DefaultTimeout);
			var maxTimeout = maxDeadTimeout.GetValueOrDefault(MaximumTimeout);
			var milliSeconds = Math.Min(timeout.TotalMilliseconds * 2 * Math.Pow(2, attempts * 0.5 - 1), maxTimeout.TotalMilliseconds);
			return Now().AddMilliseconds(milliSeconds);
		}

		public virtual DateTime Now() => DateTime.UtcNow;
	}
}