/* 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.Globalization;
using System.IO;
using OpenSearch.OpenSearch.Managed.FileSystem;
using OpenSearch.Stack.ArtifactsApi;
using OpenSearch.Stack.ArtifactsApi.Products;

namespace OpenSearch.OpenSearch.Managed.Configuration
{
	public interface IClusterConfiguration<out TFileSystem> where TFileSystem : INodeFileSystem
	{
		TFileSystem FileSystem { get; }

		string ClusterName { get; }
		NodeSettings DefaultNodeSettings { get; }
		OpenSearchVersion Version { get; }
		ServerType ServerType { get; }
		int NumberOfNodes { get; }
		int StartingPortNumber { get; set; }
		bool NoCleanupAfterNodeStopped { get; set; }

		bool ShowOpenSearchOutputAfterStarted { get; set; }
		bool CacheOpenSearchHomeInstallation { get; set; }

		string CreateNodeName(int? node);
	}

	public class ClusterConfiguration : ClusterConfiguration<NodeFileSystem>
	{
		public ClusterConfiguration(OpenSearchVersion version, ServerType serverType, string openSearchHome, int numberOfNodes = 1)
			: base(version, serverType, (v, s) => new NodeFileSystem(v, openSearchHome), numberOfNodes, null)
		{
		}

		public ClusterConfiguration(OpenSearchVersion version, ServerType serverType,
			Func<OpenSearchVersion, string, NodeFileSystem> fileSystem = null, int numberOfNodes = 1,
			string clusterName = null)
			: base(version, serverType, fileSystem ?? ((v, s) => new NodeFileSystem(v, s)), numberOfNodes, clusterName)
		{
		}
	}

	public class ClusterConfiguration<TFileSystem> : IClusterConfiguration<TFileSystem>
		where TFileSystem : INodeFileSystem
	{
		/// <summary>
		///     Creates a new instance of a configuration for an OpenSearch cluster.
		/// </summary>
		/// <param name="version">The version of OpenSearch</param>
		/// <param name="fileSystem">
		///     A delegate to create the instance of <typeparamref name="TFileSystem" />.
		///     Passed the OpenSearch version and the Cluster name
		/// </param>
		/// <param name="numberOfNodes">The number of nodes in the cluster</param>
		/// <param name="clusterName">The name of the cluster</param>
		public ClusterConfiguration(OpenSearchVersion version, ServerType serverType, Func<OpenSearchVersion, string, TFileSystem> fileSystem,
			int numberOfNodes = 1, string clusterName = null)
		{
			if (fileSystem == null) throw new ArgumentException(nameof(fileSystem));

			ClusterName = clusterName;
			Version = version;
			ServerType = serverType;
			Artifact = version.Artifact(Product.From("opensearch", serverType: serverType));
			FileSystem = fileSystem(Version, ClusterName);
			NumberOfNodes = numberOfNodes;

			var fs = FileSystem;
			Add("node.max_local_storage_nodes", numberOfNodes.ToString(CultureInfo.InvariantCulture), "1.0.0");

			Add("cluster.name", clusterName);
			Add("path.repo", fs.RepositoryPath);
			Add("path.data", fs.DataPath);
			var logsPathDefault = Path.Combine(fs.OpenSearchHome, "logs");
			if (logsPathDefault != fs.LogsPath) Add("path.logs", fs.LogsPath);
		}

		public Artifact Artifact { get; }

		public string JavaHomeEnvironmentVariable => "JAVA_HOME";

		/// <summary> Will print the contents of all the yaml files when starting the cluster up, great for debugging purposes</summary>
		public bool PrintYamlFilesInConfigFolder { get; set; }

		public string ClusterName { get; }
		public OpenSearchVersion Version { get; }
		public ServerType ServerType { get; }
		public TFileSystem FileSystem { get; }
		public int NumberOfNodes { get; }
		public int StartingPortNumber { get; set; } = 9200;
		public bool NoCleanupAfterNodeStopped { get; set; }

		/// <summary>
		///     Whether <see cref="OpenSearchNode" /> should continue to write output to console after it has started.
		///     <para>Defaults to <c>true</c></para>
		/// </summary>
		public bool ShowOpenSearchOutputAfterStarted { get; set; } = true;

		public bool CacheOpenSearchHomeInstallation { get; set; }

		/// <summary>The node settings to apply to each started node</summary>
		public NodeSettings DefaultNodeSettings { get; } = new NodeSettings();

		/// <summary>
		///     Creates a node name
		/// </summary>
		public virtual string CreateNodeName(int? node) =>
			node.HasValue ? $"managed-opensearch-{node}" : " managed-opensearch";

		/// <summary>
		///     Calculates the quorum given the number of instances
		/// </summary>
		private static int Quorum(int instanceCount) => Math.Max(1, (int) Math.Floor((double) instanceCount / 2) + 1);

		/// <summary>
		///     Creates a node attribute for the version of OpenSearch
		/// </summary>
		public string AttributeKey(string attribute)
		{
			var attr = "attr.";
			return $"node.{attr}{attribute}";
		}

		/// <summary>
		///     Adds a node setting to the default node settings
		/// </summary>
		protected void Add(string key, string value)
		{
			if (string.IsNullOrEmpty(key) || string.IsNullOrEmpty(value)) return;
			DefaultNodeSettings.Add(key, value);
		}

		/// <summary>
		///     Adds a node setting to the default node settings only if the OpenSearch
		///     version is in the range.
		/// </summary>
		protected void Add(string key, string value, string range)
		{
			if (string.IsNullOrEmpty(key) || string.IsNullOrEmpty(value)) return;
			if (string.IsNullOrWhiteSpace(range) || Version.InRange(range))
				DefaultNodeSettings.Add(key, value, range);
		}
	}
}