/* 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.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text;
using OpenSearch.OpenSearch.Xunit.XunitPlumbing;
using OpenSearch.Net;
using FluentAssertions;
using OpenSearch.Client;

namespace Tests.CodeStandards.Serialization
{
	public class Enums
	{
		[U]
		public void EnumsWithEnumMembersShouldBeMarkedWithStringEnumAttribute()
		{
			var exceptions = new HashSet<Type>
			{
				typeof(SimpleQueryStringFlags)
			};

			var enums = typeof(IOpenSearchClient).Assembly
				.GetTypes()
				.Where(t => t.IsEnum)
				.Except(exceptions)
				.ToList();
			var notMarkedStringEnum = new List<string>();
			foreach (var e in enums)
			{
				if (e.GetFields().Any(fi => fi.FieldType == e && fi.GetCustomAttribute<EnumMemberAttribute>() != null)
					&& e.GetCustomAttribute<StringEnumAttribute>() == null)
					notMarkedStringEnum.Add(e.Name);
			}
			notMarkedStringEnum.Should().BeEmpty();
		}

		[U]
		public void CanSerializeEnumsWithMultipleMembersMappedToSameValue()
		{
			var document = new EnumSameValuesDocument
			{
				Int = HttpStatusCode.Moved,
				String = AnotherEnum.Value1
			};

			var client = new OpenSearchClient();
			var json = client.RequestResponseSerializer.SerializeToString(document);

			// "Value2" will be written for both "Value1" and "Value2" because the underlying integer value
			// for both is the same, and "Value2" field member is listed after "Value1", overwriting
			// the value mapping.
			//
			// Json.Net behaves similarly, except the first string mapped for a value
			// is not overwritten i.e. "Value1" will be written for both "Value1" and "Value2"
			json.Should().Be("{\"int\":301,\"string\":\"Value2\"}");

			EnumSameValuesDocument deserializedDocument;
			using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(json)))
				deserializedDocument = client.RequestResponseSerializer.Deserialize<EnumSameValuesDocument>(stream);

			deserializedDocument.Int.Should().Be(document.Int);
			deserializedDocument.String.Should().Be(document.String);
		}

		[U]
		public void CanSerializeEnumPropertiesWithStringEnumAttribute()
		{
			var httpStatusCode = HttpStatusCode.OK;
			var document = new StringEnumDocument
			{
				Int = httpStatusCode,
				String = httpStatusCode,
				NullableString = httpStatusCode
			};

			var client = new OpenSearchClient();
			var json = client.RequestResponseSerializer.SerializeToString(document);

			json.Should().Be("{\"int\":200,\"string\":\"OK\",\"nullableString\":\"OK\"}");

			StringEnumDocument deserializedDocument;
			using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(json)))
				deserializedDocument = client.RequestResponseSerializer.Deserialize<StringEnumDocument>(stream);

			deserializedDocument.Int.Should().Be(document.Int);
			deserializedDocument.String.Should().Be(document.String);
			deserializedDocument.NullableString.Should().Be(document.NullableString);
		}

		private class StringEnumDocument
		{
			public HttpStatusCode Int { get;set;}

			[StringEnum]
			public HttpStatusCode String { get;set;}

			[StringEnum]
			public HttpStatusCode? NullableString { get;set;}
		}

		private class EnumSameValuesDocument
	    {
			public HttpStatusCode Int { get;set;}

			public AnotherEnum String { get; set; }
		}

		[StringEnum]
		public enum AnotherEnum : int
		{
			Value1 = 1,
			Value2 = 1
		}
	}
}