/* 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.Diagnostics;

namespace OpenSearch.Net.Diagnostics
{
	public static class DiagnosticSources
	{
		internal class EmptyDisposable : IDisposable
		{
			public void Dispose() { }
		}

		internal static EmptyDisposable SingletonDisposable { get; } = new EmptyDisposable();

		internal static IDisposable Diagnose<TState>(this DiagnosticSource source, string operationName, TState state)
		{
			if (!source.IsEnabled(operationName)) return SingletonDisposable;

			return new Diagnostic<TState>(operationName, source, state);
		}

		internal static Diagnostic<TState, TStateStop> Diagnose<TState, TStateStop>(this DiagnosticSource source, string operationName, TState state)
		{
			if (!source.IsEnabled(operationName)) return Diagnostic<TState, TStateStop>.Default;

			return new Diagnostic<TState, TStateStop>(operationName, source, state);
		}
		
		internal static Diagnostic<TState, TEndState> Diagnose<TState, TEndState>(this DiagnosticSource source, string operationName, TState state, TEndState endState)
		{
			if (!source.IsEnabled(operationName)) return Diagnostic<TState, TEndState>.Default;

			return new Diagnostic<TState, TEndState>(operationName, source, state)
			{
				EndState = endState
			};
			
		}

		/// <summary>
		/// When subscribing to <see cref="AuditDiagnosticKeys.SourceName"/> you will be notified of all decisions in the request pipeline
		/// </summary>
		public static AuditDiagnosticKeys AuditTrailEvents { get; } = new AuditDiagnosticKeys();

		/// <summary>
		/// When subscribing to <see cref="RequestPipelineDiagnosticKeys.SourceName"/> you will be notified every time a sniff/ping or an API call to OpenSearch happens
		/// </summary>
		public static RequestPipelineDiagnosticKeys RequestPipeline { get; } = new RequestPipelineDiagnosticKeys();

		/// <summary>
		/// When subscribing to <see cref="HttpConnectionDiagnosticKeys.SourceName"/> you will be notified every time a a connection starts and stops a request and starts and stops a a response
		/// </summary>
		public static HttpConnectionDiagnosticKeys HttpConnection { get; } = new HttpConnectionDiagnosticKeys();

		/// <summary>
		/// When subscribing to <see cref="SerializerDiagnosticKeys.SourceName"/> you will be notified every time a particular serializer writes or reads
		/// </summary>
		public static SerializerDiagnosticKeys Serializer { get; } = new SerializerDiagnosticKeys();


		private interface IDiagnosticsKeys
		{
			string SourceName { get; }
		}

		public class HttpConnectionDiagnosticKeys : IDiagnosticsKeys
		{
			public string SourceName { get; } = typeof(HttpConnection).FullName;
			public string SendAndReceiveHeaders { get; } = nameof(SendAndReceiveHeaders);
			public string ReceiveBody { get; } = nameof(ReceiveBody);
		}

		public class SerializerDiagnosticKeys : IDiagnosticsKeys
		{
			public string SourceName { get; } = typeof(IOpenSearchSerializer).FullName;
			public string Serialize { get; } = nameof(Serialize);
			public string Deserialize { get; } = nameof(Deserialize);
		}

		public class RequestPipelineDiagnosticKeys : IDiagnosticsKeys
		{
			public string SourceName { get; } = typeof(RequestPipeline).FullName;
			public string CallOpenSearch { get; } = nameof(CallOpenSearch);
			public string Ping { get; } = nameof(Ping);
			public string Sniff { get; } = nameof(Sniff);
		}

		public class AuditDiagnosticKeys : IDiagnosticsKeys
		{
			public string SourceName { get; } = typeof(Audit).FullName;
		}
	}
}