add other proxy detection for proxy

FreeSR.Tool.Proxy/Program.cs

@@ -1,4 +1,6 @@
-namespace FreeSR.Tool.Proxy
+using System.Net;
+
+namespace FreeSR.Tool.Proxy
 {
     internal static class Program
     {
@@ -10,6 +12,7 @@
         private static void Main(string[] args)
         {
             Console.Title = Title;
+            CheckProxy();
 
             s_proxyService = new ProxyService("127.0.0.1", 8888);
             AppDomain.CurrentDomain.ProcessExit += s_processExitHandler;
@@ -21,5 +24,43 @@
         {
             s_proxyService.Shutdown();
         }
+
+        public static void CheckProxy()
+        {
+            try
+            {
+                string ProxyInfo = GetProxyInfo();
+                if (ProxyInfo != null)
+                {
+                    Console.WriteLine("well... It seems you are using other proxy software(such as Clash,V2RayN,Fiddler,etc)");
+                    Console.WriteLine($"You system proxy: {ProxyInfo}");
+                    Console.WriteLine("You have to close all other proxy software to make sure FreeSR.Tool.Proxy can work well.");
+                    Console.WriteLine("Press any key to continue if you closed other proxy software, or you think you are not using other proxy.");
+                    Console.ReadKey();
+                }
+            }
+            catch (NullReferenceException)
+            {
+
+            }
+        }
+
+        public static string GetProxyInfo()
+        {
+            try
+            {
+                IWebProxy proxy = WebRequest.GetSystemWebProxy();
+                Uri proxyUri = proxy.GetProxy(new Uri("https://www.example.com"));
+
+                string proxyIP = proxyUri.Host;
+                int proxyPort = proxyUri.Port;
+                string info = proxyIP + ":" + proxyPort;
+                return info;
+            }
+            catch
+            {
+                return null;
+            }
+        }
     }
 }