Add support for fuzzy intervals in interval query

Relates: #4341

This commit adds support for fuzzy intervals source in
Intervals query

src/Nest/QueryDsl/FullText/Intervals/IntervalsFuzzy.cs

@@ -0,0 +1,107 @@
+using System;
+using System.Linq.Expressions;
+using System.Runtime.Serialization;
+
+namespace Nest
+{
+	/// <summary>
+	/// The fuzzy rule matches terms that are similar to the provided term, within an edit distance defined by Fuzziness.
+	/// If the fuzzy expansion matches more than 128 terms, Elasticsearch returns an error.
+	/// <para />
+	/// Available in Elasticsearch 7.6.0+
+	/// </summary>
+	[ReadAs(typeof(IntervalsFuzzy))]
+	public interface IIntervalsFuzzy : IIntervalsNoFilter
+	{
+		/// <summary>
+		/// Analyzer used to normalize the term. Defaults to the top-level field's analyzer.
+		/// </summary>
+		[DataMember(Name = "analyzer")]
+		string Analyzer { get; set; }
+
+		/// <summary>
+		/// Number of beginning characters left unchanged when creating expansions. Defaults to <c>0</c>.
+		/// </summary>
+		[DataMember(Name = "prefix_length")]
+		int? PrefixLength { get; set; }
+
+		/// <summary>
+		/// Indicates whether edits include transpositions of two adjacent characters (ab → ba). Defaults to <c>true</c>.
+		/// </summary>
+		[DataMember(Name = "transpositions")]
+		bool? Transpositions { get; set; }
+
+		/// <summary>
+		/// Maximum edit distance allowed for matching. See Fuzziness for valid values and more information.
+		/// Defaults to <see cref="Nest.Fuzziness.Auto"/>.
+		/// </summary>
+		[DataMember(Name = "fuzziness")]
+		Fuzziness Fuzziness { get; set; }
+
+		/// <summary>
+		/// The term to match.
+		/// </summary>
+		[DataMember(Name = "term")]
+		string Term { get; set; }
+
+		/// <summary>
+		/// If specified, then match intervals from this field rather than the top-level field.
+		/// The term is normalized using the search analyzer from this field,
+		/// unless analyzer is specified separately.
+		/// </summary>
+		[DataMember(Name = "use_field")]
+		Field UseField { get; set; }
+	}
+
+	/// <inheritdoc cref="IIntervalsFuzzy" />
+	public class IntervalsFuzzy : IntervalsNoFilterBase, IIntervalsFuzzy
+	{
+		internal override void WrapInContainer(IIntervalsContainer container) => container.Fuzzy = this;
+
+		/// <inheritdoc />
+		public string Analyzer { get; set; }
+		/// <inheritdoc />
+		public int? PrefixLength { get; set; }
+		/// <inheritdoc />
+		public bool? Transpositions { get; set; }
+		/// <inheritdoc />
+		public Fuzziness Fuzziness { get; set; }
+		/// <inheritdoc />
+		public string Term { get; set; }
+		/// <inheritdoc />
+		public Field UseField { get; set; }
+	}
+
+	/// <inheritdoc cref="IIntervalsFuzzy" />
+	public class IntervalsFuzzyDescriptor : DescriptorBase<IntervalsFuzzyDescriptor, IIntervalsFuzzy>, IIntervalsFuzzy
+	{
+		string IIntervalsFuzzy.Analyzer { get; set; }
+		int? IIntervalsFuzzy.PrefixLength { get; set; }
+		bool? IIntervalsFuzzy.Transpositions { get; set; }
+		Fuzziness IIntervalsFuzzy.Fuzziness { get; set; }
+		string IIntervalsFuzzy.Term { get; set; }
+		Field IIntervalsFuzzy.UseField { get; set; }
+
+		/// <inheritdoc cref="IIntervalsFuzzy.Analyzer" />
+		public IntervalsFuzzyDescriptor Analyzer(string analyzer) => Assign(analyzer, (a, v) => a.Analyzer = v);
+
+		/// <inheritdoc cref="IIntervalsFuzzy.PrefixLength" />
+		public IntervalsFuzzyDescriptor PrefixLength(int? prefixLength) => Assign(prefixLength, (a, v) => a.PrefixLength = v);
+
+		/// <inheritdoc cref="IIntervalsFuzzy.Transpositions" />
+		public IntervalsFuzzyDescriptor Transpositions(bool? transpositions = true) => Assign(transpositions, (a, v) => a.Transpositions = v);
+
+		/// <inheritdoc cref="IIntervalsFuzzy.Fuzziness" />
+		public IntervalsFuzzyDescriptor Fuzziness(Fuzziness fuzziness) => Assign(fuzziness, (a, v) => a.Fuzziness = v);
+
+		/// <inheritdoc cref="IIntervalsFuzzy.Term" />
+		public IntervalsFuzzyDescriptor Term(string term) => Assign(term, (a, v) => a.Term = v);
+
+
+		/// <inheritdoc cref="IIntervalsFuzzy.UseField" />
+		public IntervalsFuzzyDescriptor UseField<T>(Expression<Func<T, object>> objectPath) => Assign(objectPath, (a, v) => a.UseField = v);
+
+		/// <inheritdoc cref="IIntervalsFuzzy.UseField" />
+		public IntervalsFuzzyDescriptor UseField(Field useField) => Assign(useField, (a, v) => a.UseField = v);
+	}
+}

src/Nest/QueryDsl/FullText/Intervals/IntervalsQuery.cs

@@ -25,6 +25,8 @@ public class IntervalsQuery : FieldNameQueryBase, IIntervalsQuery
 		public IIntervalsAnyOf AnyOf { get; set; }
 		/// <inheritdoc cref="IIntervalsMatch"/>
 		public IIntervalsMatch Match { get; set; }
+		/// <inheritdoc cref="IIntervalsFuzzy"/>
+		public IIntervalsFuzzy Fuzzy { get; set; }
 
 		/// <inheritdoc cref="IIntervalsPrefix"/>
 		public IIntervalsPrefix Prefix { get; set; }
@@ -35,7 +37,8 @@ public class IntervalsQuery : FieldNameQueryBase, IIntervalsQuery
 		protected override bool Conditionless => IsConditionless(this);
 
 		internal static bool IsConditionless(IIntervalsQuery q) =>
-			q.Field.IsConditionless() || q.Match == null && q.AllOf == null && q.AnyOf == null && q.Prefix == null && q.Wildcard == null;
+			q.Field.IsConditionless() || q.Match == null && q.AllOf == null && q.AnyOf == null && q.Prefix == null && q.Wildcard == null
+			&& q.Fuzzy == null;
 
 		internal override void InternalWrapInContainer(IQueryContainer container) => container.Intervals = this;
 	}
@@ -50,10 +53,15 @@ public class IntervalsQueryDescriptor<T>
 
 		IIntervalsAllOf IIntervalsContainer.AllOf { get; set; }
 		IIntervalsAnyOf IIntervalsContainer.AnyOf { get; set; }
+		IIntervalsFuzzy IIntervalsContainer.Fuzzy { get; set; }
 		IIntervalsMatch IIntervalsContainer.Match { get; set; }
 		IIntervalsPrefix IIntervalsContainer.Prefix { get; set; }
 		IIntervalsWildcard IIntervalsContainer.Wildcard { get; set; }
 
+		/// <inheritdoc cref="IntervalsQuery.Fuzzy" />
+		public IntervalsQueryDescriptor<T> Fuzzy(Func<IntervalsFuzzyDescriptor, IIntervalsFuzzy> selector) =>
+			Assign(selector, (a, v) => a.Fuzzy = v?.Invoke(new IntervalsFuzzyDescriptor()));
+
 		/// <inheritdoc cref="IntervalsQuery.Match" />
 		public IntervalsQueryDescriptor<T> Match(Func<IntervalsMatchDescriptor, IIntervalsMatch> selector) =>
 			Assign(selector, (a, v) => a.Match = v?.Invoke(new IntervalsMatchDescriptor()));
@@ -88,6 +96,10 @@ public interface IIntervalsContainer
 		[DataMember(Name = "any_of")]
 		IIntervalsAnyOf AnyOf { get; set; }
 
+		/// <inheritdoc cref="IIntervalsFuzzy" />
+		[DataMember(Name = "fuzzy")]
+		IIntervalsFuzzy Fuzzy { get; set; }
+
 		/// <inheritdoc cref="IIntervalsMatch" />
 		[DataMember(Name = "match")]
 		IIntervalsMatch Match { get; set; }
@@ -120,6 +132,7 @@ public IntervalsContainer(IntervalsNoFilterBase intervals)
 
 		IIntervalsAllOf IIntervalsContainer.AllOf { get; set; }
 		IIntervalsAnyOf IIntervalsContainer.AnyOf { get; set; }
+		IIntervalsFuzzy IIntervalsContainer.Fuzzy { get; set; }
 		IIntervalsMatch IIntervalsContainer.Match { get; set; }
 		IIntervalsPrefix IIntervalsContainer.Prefix { get; set; }
 		IIntervalsWildcard IIntervalsContainer.Wildcard { get; set; }
@@ -141,6 +154,10 @@ public class IntervalsDescriptor : IntervalsContainer
 		private IntervalsDescriptor Assign<TValue>(TValue value, Action<IIntervalsContainer, TValue> assigner) =>
 			Fluent.Assign(this, value, assigner);
 
+		/// <inheritdoc cref="IntervalsFuzzyDescriptor" />
+		public IntervalsDescriptor Fuzzy(Func<IntervalsFuzzyDescriptor, IIntervalsFuzzy> selector) =>
+			Assign(selector, (a, v) => a.Fuzzy = v?.Invoke(new IntervalsFuzzyDescriptor()));
+
 		/// <inheritdoc cref="IntervalsMatchDescriptor" />
 		public IntervalsDescriptor Match(Func<IntervalsMatchDescriptor, IIntervalsMatch> selector) =>
 			Assign(selector, (a, v) => a.Match = v?.Invoke(new IntervalsMatchDescriptor()));
@@ -222,6 +239,10 @@ public class IntervalsListDescriptor : DescriptorPromiseBase<IntervalsListDescri
 	{
 		public IntervalsListDescriptor() : base(new List<IntervalsContainer>()) { }
 
+		/// <inheritdoc cref="IIntervalsFuzzy" />
+		public IntervalsListDescriptor Fuzzy(Func<IntervalsFuzzyDescriptor, IIntervalsFuzzy> selector) =>
+			Assign(selector, (a, v) => a.AddIfNotNull(new IntervalsDescriptor().Fuzzy(v)));
+
 		/// <inheritdoc cref="IIntervalsMatch" />
 		public IntervalsListDescriptor Match(Func<IntervalsMatchDescriptor, IIntervalsMatch> selector) =>
 			Assign(selector, (a, v) => a.AddIfNotNull(new IntervalsDescriptor().Match(v)));

tests/Tests/QueryDsl/FullText/Intervals/IntervalsUsageTests.cs

@@ -262,4 +262,62 @@ protected override QueryContainer QueryFluent(QueryContainerDescriptor<Project>
 				)
 			);
 	}
+
+	/**[float]
+	 * === Fuzzy rules
+	 *
+	 * Fuzzy rules can be used to match terms that are similar to the provided term, within an edit distance defined by Fuzziness.
+	 * If the fuzzy expansion matches more than 128 terms, Elasticsearch returns an error.
+	 *
+	 * NOTE: Only available in Elasticsearch 7.6.0+
+	 */
+	[SkipVersion("<7.6.0", "fuzzy rules introduced in 7.6.0")]
+	public class IntervalsFuzzyUsageTests : QueryDslUsageTestsBase
+	{
+		public IntervalsFuzzyUsageTests(ReadOnlyCluster i, EndpointUsage usage) : base(i, usage) { }
+
+		private static readonly string IntervalsPrefix = Project.First.Description.Split(' ')[0];
+
+		private static readonly string IntervalsFuzzy = IntervalsPrefix.Substring(0, IntervalsPrefix.Length) + "z";
+
+		protected override QueryContainer QueryInitializer => new IntervalsQuery
+		{
+			Field = Field<Project>(p => p.Description),
+			Name = "named_query",
+			Boost = 1.1,
+			Fuzzy = new IntervalsFuzzy
+			{
+				Term = IntervalsFuzzy,
+				Fuzziness = Fuzziness.Auto
+			}
+		};
+
+		protected override object QueryJson => new
+		{
+			intervals = new
+			{
+				description = new
+				{
+					_name = "named_query",
+					boost = 1.1,
+					fuzzy = new
+					{
+						term = IntervalsFuzzy,
+						fuzziness = "AUTO"
+					}
+				}
+			}
+		};
+
+		protected override QueryContainer QueryFluent(QueryContainerDescriptor<Project> q) => q
+			.Intervals(c => c
+				.Field(p => p.Description)
+				.Name("named_query")
+				.Boost(1.1)
+				.Fuzzy(m => m
+					.Term(IntervalsFuzzy)
+					.Fuzziness(Fuzziness.Auto)
+				)
+			);
+	}
 }