From e4c0a62f8a076334c7f99c4bb3bea251bced2966 Mon Sep 17 00:00:00 2001
From: KSP-TaxiService <chinglihlim@gmail.com>
Date: Mon, 26 Jul 2021 22:21:10 +0800
Subject: [PATCH] Fix bug of valid connection displayed in wrong constellation
 colour

---
 .../CommNetLayer/CNCCommNetUI.cs              | 11 ++++++++
 .../CommNetLayer/CNCCommNetVessel.cs          | 27 +++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/src/CommNetConstellation/CommNetLayer/CNCCommNetUI.cs b/src/CommNetConstellation/CommNetLayer/CNCCommNetUI.cs
index ecae431..0fc6069 100644
--- a/src/CommNetConstellation/CommNetLayer/CNCCommNetUI.cs
+++ b/src/CommNetConstellation/CommNetLayer/CNCCommNetUI.cs
@@ -170,6 +170,17 @@ private Color getConstellationColor(CommNode a, CommNode b)
                     continue;
                 }
 
+                //ensure connection can be established on this frequency (eg 1<->1 not 1<->2)
+                if (a.isHome != true && b.isHome != true) //skip if either A or B CommNet Home (always relay)
+                {
+                    var vesselA = (a.GetVessel().connection as IModularCommNetVessel).GetModuleOfType<CNCCommNetVessel>();
+                    var vesselB = (b.GetVessel().connection as IModularCommNetVessel).GetModuleOfType<CNCCommNetVessel>();
+                    if (!vesselA.isConnectionEligible(vesselB, commonFreqs[i]))
+                    {
+                        continue;
+                    }
+                }
+
                 thisRange = CNCCommNetScenario.RangeModel.GetMaximumRange(CNCCommNetScenario.Instance.getCommPower(a, commonFreqs[i]), CNCCommNetScenario.Instance.getCommPower(b, commonFreqs[i]));
                 if(thisRange > longestRange)
                 {
diff --git a/src/CommNetConstellation/CommNetLayer/CNCCommNetVessel.cs b/src/CommNetConstellation/CommNetLayer/CNCCommNetVessel.cs
index 3815d61..d7a1a84 100644
--- a/src/CommNetConstellation/CommNetLayer/CNCCommNetVessel.cs
+++ b/src/CommNetConstellation/CommNetLayer/CNCCommNetVessel.cs
@@ -92,6 +92,8 @@ public enum FrequencyListOperation
         protected bool stageActivated = false;
         public bool IsCommandable = true;
 
+        public List<CNCAntennaPartInfo> Antennas { get { return vesselAntennas; } }
+
         /// <summary>
         /// Retrieve the CNC data from the vessel, in addition of stock network joining
         /// </summary>
@@ -893,5 +895,30 @@ protected void groundSciencePartStateChange(ModuleGroundSciencePart sciencePart)
                 this.rebuildFreqList(true);
             }
         }
+
+        /// <summary>
+        /// Check if this and target vessels can establish connection of specific frequency
+        /// </summary>
+        public bool isConnectionEligible(CNCCommNetVessel otherVessel, short targetFreq)
+        {
+            for(int i = 0; i < this.vesselAntennas.Count; i++)
+            {
+                if(this.vesselAntennas[i].frequency == targetFreq)
+                {
+                    for(int j = 0; j < otherVessel.Antennas.Count; j++)
+                    {
+                        if (otherVessel.Antennas[j].frequency == targetFreq)
+                        {
+                            if(this.vesselAntennas[i].antennaType == AntennaType.RELAY || otherVessel.Antennas[j].antennaType == AntennaType.RELAY)
+                            {
+                                return true;
+                            }
+                        }
+                    }
+                }
+            }
+
+            return false; //cannot connect to each other
+        }
     }
 }