/* 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 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;

namespace Tests.Aggregations.Bucket.SignificantTerms
{
	/**
	 * An aggregation that returns interesting or unusual occurrences of terms in a set.
	 *
	 * [WARNING]
	 * --
	 * The significant_terms aggregation can be very heavy when run on large indices. Work is in progress
	 * to provide more lightweight sampling techniques.
	 * As a result, the API for this feature may change in non-backwards compatible ways
	 * --
	 *
	 * See the OpenSearch documentation on {ref_current}/search-aggregations-bucket-significantterms-aggregation.html[significant terms aggregation] for more detail.
	 */
	public class SignificantTermsAggregationUsageTests : AggregationUsageTestBase<ReadOnlyCluster>
	{
		public SignificantTermsAggregationUsageTests(ReadOnlyCluster i, EndpointUsage usage) : base(i, usage) { }

		protected override object AggregationJson => new
		{
			significant_names = new
			{
				significant_terms = new
				{
					field = "name",
					min_doc_count = 10,
					mutual_information = new
					{
						background_is_superset = true,
						include_negatives = true
					}
				}
			}
		};

		protected override Func<AggregationContainerDescriptor<Project>, IAggregationContainer> FluentAggs => a => a
			.SignificantTerms("significant_names", st => st
				.Field(p => p.Name)
				.MinimumDocumentCount(10)
				.MutualInformation(mi => mi
					.BackgroundIsSuperSet()
					.IncludeNegatives()
				)
			);

		protected override AggregationDictionary InitializerAggs =>
			new SignificantTermsAggregation("significant_names")
			{
				Field = Field<Project>(p => p.Name),
				MinimumDocumentCount = 10,
				MutualInformation = new MutualInformationHeuristic
				{
					BackgroundIsSuperSet = true,
					IncludeNegatives = true
				}
			};

		protected override void ExpectResponse(ISearchResponse<Project> response)
		{
			response.ShouldBeValid();
			var sigNames = response.Aggregations.SignificantTerms("significant_names");
			sigNames.Should().NotBeNull();
			sigNames.DocCount.Should().BeGreaterThan(0);
		}
	}

	/**
	 * [float]
	 * [[significant-terms-pattern-filter]]
	 * == Filtering with a regular expression pattern
	 *
	 * Using significant terms aggregation with filtering to include values using a regular expression pattern
	 */
	public class SignificantTermsIncludePatternAggregationUsageTests : AggregationUsageTestBase<ReadOnlyCluster>
	{
		public SignificantTermsIncludePatternAggregationUsageTests(ReadOnlyCluster i, EndpointUsage usage) : base(i, usage) { }

		protected override object AggregationJson => new
		{
			significant_names = new
			{
				significant_terms = new
				{
					field = "name",
					min_doc_count = 10,
					mutual_information = new
					{
						background_is_superset = true,
						include_negatives = true
					},
					include = "pi*"
				}
			}
		};

		protected override Func<AggregationContainerDescriptor<Project>, IAggregationContainer> FluentAggs => a => a
			.SignificantTerms("significant_names", st => st
				.Field(p => p.Name)
				.MinimumDocumentCount(10)
				.MutualInformation(mi => mi
					.BackgroundIsSuperSet()
					.IncludeNegatives()
				)
				.Include("pi*")
			);

		protected override AggregationDictionary InitializerAggs =>
			new SignificantTermsAggregation("significant_names")
			{
				Field = Field<Project>(p => p.Name),
				MinimumDocumentCount = 10,
				MutualInformation = new MutualInformationHeuristic
				{
					BackgroundIsSuperSet = true,
					IncludeNegatives = true
				},
				Include = new IncludeExclude("pi*")
			};

		protected override void ExpectResponse(ISearchResponse<Project> response)
		{
			response.ShouldBeValid();
			var sigNames = response.Aggregations.SignificantTerms("significant_names");
			sigNames.Should().NotBeNull();
			sigNames.DocCount.Should().BeGreaterThan(0);
		}
	}

	/**
	 * [float]
	 * [[significant-terms-exact-value-filter]]
	 * == Filtering with exact values
	 *
	 * Using significant terms aggregation with filtering to exclude specific values
	 */
	public class SignificantTermsExcludeExactValuesAggregationUsageTests : AggregationUsageTestBase<ReadOnlyCluster>
	{
		public SignificantTermsExcludeExactValuesAggregationUsageTests(ReadOnlyCluster i, EndpointUsage usage) : base(i, usage) { }

		protected override object AggregationJson => new
		{
			significant_names = new
			{
				significant_terms = new
				{
					field = "name",
					min_doc_count = 10,
					mutual_information = new
					{
						background_is_superset = true,
						include_negatives = true
					},
					exclude = new[] { "pierce" }
				}
			}
		};

		protected override Func<AggregationContainerDescriptor<Project>, IAggregationContainer> FluentAggs => a => a
			.SignificantTerms("significant_names", st => st
				.Field(p => p.Name)
				.MinimumDocumentCount(10)
				.MutualInformation(mi => mi
					.BackgroundIsSuperSet()
					.IncludeNegatives()
				)
				.Exclude(new[] { "pierce" })
			);

		protected override AggregationDictionary InitializerAggs =>
			new SignificantTermsAggregation("significant_names")
			{
				Field = Field<Project>(p => p.Name),
				MinimumDocumentCount = 10,
				MutualInformation = new MutualInformationHeuristic
				{
					BackgroundIsSuperSet = true,
					IncludeNegatives = true
				},
				Exclude = new IncludeExclude(new[] { "pierce" })
			};

		protected override void ExpectResponse(ISearchResponse<Project> response)
		{
			response.ShouldBeValid();
			var sigNames = response.Aggregations.SignificantTerms("significant_names");
			sigNames.Should().NotBeNull();
			sigNames.DocCount.Should().BeGreaterThan(0);
		}
	}

	/**
	 * [float]
	 * [[significant-terms-numeric-field]]
	 * == Numeric fields
	 *
	 * A significant terms aggregation on a numeric field
	 */
	public class NumericSignificantTermsAggregationUsageTests : AggregationUsageTestBase<ReadOnlyCluster>
	{
		public NumericSignificantTermsAggregationUsageTests(ReadOnlyCluster i, EndpointUsage usage) : base(i, usage) { }

		protected override object AggregationJson => new
		{
			commits = new
			{
				significant_terms = new
				{
					field = "numberOfContributors"
				}
			}
		};

		protected override Func<AggregationContainerDescriptor<Project>, IAggregationContainer> FluentAggs => a => a
			.SignificantTerms("commits", st => st
				.Field(p => p.NumberOfContributors)
			);

		protected override AggregationDictionary InitializerAggs =>
			new SignificantTermsAggregation("commits")
			{
				Field = Field<Project, int>(p => p.NumberOfContributors)
			};

		protected override void ExpectResponse(ISearchResponse<Project> response)
		{
			response.ShouldBeValid();
			var commits = response.Aggregations.SignificantTerms<int>("commits");
			commits.Should().NotBeNull();
			commits.Buckets.Should().NotBeNull();
			commits.Buckets.Count.Should().BeGreaterThan(0);
			foreach (var item in commits.Buckets)
			{
				item.Key.Should().BeGreaterThan(0);
				item.DocCount.Should().BeGreaterOrEqualTo(1);
			}
		}
	}
}