//     _                _      _  ____   _                           _____
//    / \    _ __  ___ | |__  (_)/ ___| | |_  ___   __ _  _ __ ___  |  ___|__ _  _ __  _ __ ___
//   / _ \  | '__|/ __|| '_ \ | |\___ \ | __|/ _ \ / _` || '_ ` _ \ | |_  / _` || '__|| '_ ` _ \
//  / ___ \ | |  | (__ | | | || | ___) || |_|  __/| (_| || | | | | ||  _|| (_| || |   | | | | | |
// /_/   \_\|_|   \___||_| |_||_||____/  \__|\___| \__,_||_| |_| |_||_|   \__,_||_|   |_| |_| |_|
// 
//  Copyright 2015-2018 Łukasz "JustArchi" Domeradzki
//  Contact: JustArchi@JustArchi.net
// 
//  Licensed 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.Linq;
using System.Threading.Tasks;
using Newtonsoft.Json;
using SteamKit2.Discovery;

namespace ArchiSteamFarm {
	internal sealed class InMemoryServerListProvider : IServerListProvider {
		[JsonProperty(Required = Required.DisallowNull)]
		private readonly ConcurrentHashSet<ServerRecordEndPoint> ServerRecords = new ConcurrentHashSet<ServerRecordEndPoint>();

		public Task<IEnumerable<ServerRecord>> FetchServerListAsync() => Task.FromResult(ServerRecords.Select(server => ServerRecord.CreateServer(server.Host, server.Port, server.ProtocolTypes)));

		public Task UpdateServerListAsync(IEnumerable<ServerRecord> endpoints) {
			if (endpoints == null) {
				ASF.ArchiLogger.LogNullError(nameof(endpoints));
				return Task.CompletedTask;
			}

			HashSet<ServerRecordEndPoint> newServerRecords = new HashSet<ServerRecordEndPoint>(endpoints.Select(ep => new ServerRecordEndPoint(ep.GetHost(), (ushort) ep.GetPort(), ep.ProtocolTypes)));

			if (!ServerRecords.ReplaceIfNeededWith(newServerRecords)) {
				return Task.CompletedTask;
			}

			ServerListUpdated?.Invoke(this, EventArgs.Empty);
			return Task.CompletedTask;
		}

		internal event EventHandler ServerListUpdated;
	}
}