/* 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 System.Linq.Expressions;
using System.Runtime.Serialization;
using OpenSearch.Net.Utf8Json;

namespace OpenSearch.Client
{
	[InterfaceDataContract]
	[JsonFormatter(typeof(SpanGapQueryFormatter))]
	public interface ISpanGapQuery : ISpanSubQuery
	{
		Field Field { get; set; }

		int? Width { get; set; }
	}

	public class SpanGapQuery : QueryBase, ISpanGapQuery
	{
		public Field Field { get; set; }
		public int? Width { get; set; }
		protected override bool Conditionless => IsConditionless(this);

		internal static bool IsConditionless(ISpanGapQuery q) => q?.Width == null || q.Field.IsConditionless();

		internal override void InternalWrapInContainer(IQueryContainer c) =>
			throw new Exception("span_gap may only appear as a span near clause");
	}

	[DataContract]
	public class SpanGapQueryDescriptor<T> : QueryDescriptorBase<SpanGapQueryDescriptor<T>, ISpanGapQuery>, ISpanGapQuery
		where T : class
	{
		protected override bool Conditionless => SpanGapQuery.IsConditionless(this);

		Field ISpanGapQuery.Field { get; set; }

		int? ISpanGapQuery.Width { get; set; }

		public SpanGapQueryDescriptor<T> Field(Field field) => Assign(field, (a, v) => a.Field = v);

		public SpanGapQueryDescriptor<T> Field<TValue>(Expression<Func<T, TValue>> objectPath) => Assign(objectPath, (a, v) => a.Field = v);

		public SpanGapQueryDescriptor<T> Width(int? width) => Assign(width, (a, v) => a.Width = v);
	}

	internal class SpanGapQueryFormatter : IJsonFormatter<ISpanGapQuery>
	{
		public void Serialize(ref JsonWriter writer, ISpanGapQuery value, IJsonFormatterResolver formatterResolver)
		{
			if (value == null || SpanGapQuery.IsConditionless(value))
			{
				writer.WriteNull();
				return;
			}

			writer.WriteBeginObject();
			var inferrer = formatterResolver.GetConnectionSettings().Inferrer;
			writer.WritePropertyName(inferrer.Field(value.Field));
			writer.WriteInt32(value.Width.Value);
			writer.WriteEndObject();
		}

		public ISpanGapQuery Deserialize(ref JsonReader reader, IJsonFormatterResolver formatterResolver)
		{
			if (reader.GetCurrentJsonToken() == JsonToken.Null)
			{
				reader.ReadNext();
				return null;
			}

			var count = 0;
			var query = new SpanGapQuery();

			while (reader.ReadIsInObject(ref count))
			{
				if (count > 1)
					continue;

				query.Field = reader.ReadPropertyName();
				query.Width = reader.ReadInt32();
			}

			return query;
		}
	}
}