refactor FileTransferService to use stateful initialization and naming conventions

Services/FileTransferService.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Chtn.CSharp.SDK.Core;
+using Chtn.CSharp.SDK.Models.Media;
+
+namespace Chtn.CSharp.SDK.Services
+{
+    public interface IFileTransferService
+    {
+        Task<StartNewFileTransferResp> StartNew(string targetUserId, string fileName, long fileSize);
+        Task Accept(string transferId);
+        Task Decline(string transferId);
+        Task SendRtcOffer(string transferId, object offer);
+        Task SendRtcAnswer(string transferId, object answer);
+        Task SendRtcIce(string transferId, object ice);
+    }
+
+    public class FileTransferService : IFileTransferService
+    {
+        private readonly ApiClient _apiClient;
+        private readonly string _userId;
+        private readonly object _webSocket;
+
+        public FileTransferService(ApiClient apiClient, string userId, object webSocket)
+        {
+            _apiClient = apiClient ?? throw new ArgumentNullException(nameof(ApiClient));
+            _userId = userId;
+            _webSocket = webSocket ?? throw new ArgumentNullException(nameof(webSocket));
+        }
+
+        public async Task<StartNewFileTransferResp> StartNew(string targetUserId, string fileName, long fileSize)
+        {
+            var body = new { userid = _userId, targetId = targetUserId, name = fileName, size = fileSize };
+            return await _apiClient.PostAsync<object, StartNewFileTransferResp>("v2/chat/dm/startNewFileTransfer", body);
+        }
+
+        public async Task Accept(string transferId)
+        {
+            var body = new { userid = _userId, transferId = transferId };
+            await _apiClient.PostAsync<object, object>("v2/chat/dm/acceptFileTransfer", body);
+        }
+
+        public async Task Decline(string transferId)
+        {
+            var body = new { userid = _userId, transferId = transferId };
+            await _apiClient.PostAsync<object, object>("v2/chat/dm/declineFileTransfer", body);
+        }
+
+        public async Task SendRtcOffer(string transferId, object offer)
+        {
+            var body = new { userid = _userId, transferId = transferId, offer = offer };
+            await _apiClient.PostAsync<object, object>("v2/chat/dm/sendRtcOfferFileTransfer", body);
+        }
+
+        public async Task SendRtcAnswer(string transferId, object answer)
+        {
+            var body = new { userid = _userId, transferId = transferId, answer = answer };
+            await _apiClient.PostAsync<object, object>("v2/chat/dm/sendRtcAnswerFileTransfer", body);
+        }
+
+        public async Task SendRtcIce(string transferId, object ice)
+        {
+            var body = new { userid = _userId, transferId = transferId, ice = ice };
+            await _apiClient.PostAsync<object, object>("v2/chat/dm/sendRtcICEFileTransfer", body);
+        }
+    }
+}