/* 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 OpenSearch.OpenSearch.Xunit.XunitPlumbing;
using FluentAssertions;
using OpenSearch.Client;
using Tests.Core.Extensions;
using Tests.Core.ManagedOpenSearch.Clusters;
using Tests.Domain;
using Tests.Framework.EndpointTests.TestState;
using static OpenSearch.Client.Infer;
using ValueType = OpenSearch.Client.ValueType;

namespace Tests.Aggregations.Metric.WeightedAverage
{
	/**
	 * A single-value metrics aggregation that computes the weighted average of numeric values that are extracted
	 * from the aggregated documents. These values can be extracted either from specific numeric fields in the documents.
	 * When calculating a regular average, each datapoint has an equal "weight" i.e. it contributes equally to the final
	 * value. Weighted averages, on the other hand, weight each datapoint differently. The amount that each
	 * datapoint contributes to the final value is extracted from the document, or provided by a script.
	 *
	 * Be sure to read the OpenSearch documentation on {ref_current}/search-aggregations-metrics-weight-avg-aggregation.html[Weighted Avg Aggregation]
	 */
	public class WeightedAverageAggregationUsageTests : AggregationUsageTestBase<ReadOnlyCluster>
	{
		public WeightedAverageAggregationUsageTests(ReadOnlyCluster i, EndpointUsage usage) : base(i, usage) { }

		protected override object AggregationJson => new
		{
			weighted_avg_commits = new
			{
				weighted_avg = new
				{
					value = new
					{
						field = "numberOfCommits",
						missing = 0.0
					},
					weight = new
					{
						script = new
						{
							source = "(doc['numberOfContributors']?.value ?: 0) + 1"
						}
					},
					value_type = "long"
				}
			}
		};

		protected override Func<AggregationContainerDescriptor<Project>, IAggregationContainer> FluentAggs => a => a
			.WeightedAverage("weighted_avg_commits", avg => avg
				.Value(v => v.Field(p => p.NumberOfCommits).Missing(0))
				.Weight(w => w.Script("(doc['numberOfContributors']?.value ?: 0) + 1"))
				.ValueType(ValueType.Long)
			);

		protected override AggregationDictionary InitializerAggs =>
			new WeightedAverageAggregation("weighted_avg_commits")
			{
				Value = new WeightedAverageValue(Field<Project>(p => p.NumberOfCommits))
				{
					Missing = 0
				},
				Weight = new WeightedAverageValue(new InlineScript("(doc['numberOfContributors']?.value ?: 0) + 1")),
				ValueType = ValueType.Long
			};

		protected override void ExpectResponse(ISearchResponse<Project> response)
		{
			response.ShouldBeValid();
			var commitsAvg = response.Aggregations.WeightedAverage("weighted_avg_commits");
			commitsAvg.Should().NotBeNull();
			commitsAvg.Value.Should().BeGreaterThan(0);
		}
	}
}