fix(singbox): preserve Hysteria2 hop interval ranges (#10576)

* fix(singbox): use both bounds of Hysteria2 hop interval

* fix(singbox): preserve native Hysteria2 hop interval bounds

v2rayN/ServiceLib.Tests/CoreConfig/Singbox/CoreConfigSingboxServiceTests.cs

@@ -715,6 +715,32 @@ public class CoreConfigSingboxServiceTests
         }
     }
 
+    [Test]
+    [Arguments("5-15", "5s", "15s")]
+    [Arguments("20-25", "20s", "25s")]
+    [Arguments("15", "15s", null)]
+    [Arguments("4-10", "30s", null)]
+    [Arguments("15-5", "30s", null)]
+    public async Task GenerateClientConfigContent_Hysteria2HopInterval_ShouldPreserveRange(string interval, string expected, string? expectedMax)
+    {
+        var node = Hysteria2Fmt.Resolve("hysteria2://password@example.com:443?mport=20000-50000", out _)!;
+        node.CoreType = ECoreType.sing_box;
+        node.SetProtocolExtra(node.GetProtocolExtra() with { HopInterval = interval });
+
+        var config = CoreConfigTestFactory.CreateConfig(ECoreType.sing_box);
+        config.HysteriaItem.HopInterval = 30;
+        CoreConfigTestFactory.BindAppManagerConfig(config);
+        var context = CoreConfigTestFactory.CreateContext(config, node, ECoreType.sing_box);
+
+        var result = new CoreConfigSingboxService(context).GenerateClientConfigContent();
+
+        await result.Success.Should().BeTrue().Because($"ret msg: {result.Msg}");
+        var cfg = JsonUtils.Deserialize<SingboxConfig>(result.Data!.ToString())!;
+        var proxy = cfg.outbounds.First(o => o.tag == Global.ProxyTag);
+        await proxy.hop_interval.Should().BeEqualTo(expected);
+        await proxy.hop_interval_max.Should().BeEqualTo(expectedMax);
+    }
+
     [Test]
     public async Task GenerateClientConfigContent_Hysteria2Realm_ShouldEmitHttpsServerUrl()
     {

v2rayN/ServiceLib/Models/CoreConfigs/SingboxConfig.cs

@@ -133,6 +133,7 @@ public class Outbound4Sbox : BaseServer4Sbox
     public int? alter_id { get; set; }
     public string? flow { get; set; }
     public string? hop_interval { get; set; }
+    public string? hop_interval_max { get; set; }
     public int? up_mbps { get; set; }
     public int? down_mbps { get; set; }
     public string? auth_str { get; set; }

v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxOutboundService.cs

@@ -277,13 +277,12 @@ public partial class CoreConfigSingboxService
                             }
                             else if (protocolExtra.HopInterval?.Contains('-') ?? false)
                             {
-                                // may be a range like 5-10
                                 var parts = protocolExtra.HopInterval.Split('-');
                                 if (parts.Length == 2 && int.TryParse(parts[0], out var hiL) &&
-                                    int.TryParse(parts[0], out var hiH))
+                                    int.TryParse(parts[1], out var hiH) && hiL >= 5 && hiH >= hiL)
                                 {
-                                    var hi = (hiL + hiH) / 2;
+                                    outbound.hop_interval = $"{hiL}s";
-                                    outbound.hop_interval = hi >= 5 ? $"{hi}s" : outbound.hop_interval;
+                                    outbound.hop_interval_max = $"{hiH}s";
                                 }
                             }
                         }