/* 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.Collections.Generic;
using System.Linq;
using OpenSearch.Net.Utf8Json;

namespace OpenSearch.Client
{
	public class TopHitsAggregate : MetricAggregateBase
	{
		private readonly IJsonFormatterResolver _formatterResolver;
		private readonly IList<LazyDocument> _hits;

		public TopHitsAggregate() { }

		internal TopHitsAggregate(IList<LazyDocument> hits, IJsonFormatterResolver formatterResolver)
		{
			_hits = hits;
			_formatterResolver = formatterResolver;
		}

		public double? MaxScore { get; set; }

		public TotalHits Total { get; set; }

		private IEnumerable<IHit<TDocument>> ConvertHits<TDocument>()
			where TDocument : class
		{
			var formatter = _formatterResolver.GetFormatter<IHit<TDocument>>();
			return _hits.Select(h =>
			{
				var reader = new JsonReader(h.Bytes);
				return formatter.Deserialize(ref reader, _formatterResolver);
			});
		}

		public IReadOnlyCollection<IHit<TDocument>> Hits<TDocument>()
			where TDocument : class =>
			ConvertHits<TDocument>().ToList().AsReadOnly();

		public IReadOnlyCollection<TDocument> Documents<TDocument>() where TDocument : class =>
			ConvertHits<TDocument>().Select(h => h.Source).ToList().AsReadOnly();
	}
}