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NitroxPatcher/Patches/Dynamic/CyclopsSonarButton_Update_Patch.cs

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+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Reflection.Emit;
+using HarmonyLib;
+using NitroxClient.MonoBehaviours.Cyclops;
+using NitroxClient.MonoBehaviours.Vehicles;
+using NitroxModel.Helper;
+
+namespace NitroxPatcher.Patches.Dynamic;
+
+/// <summary>
+/// Prevents sonar from turning off automatically for the player that isn't currently piloting the Cyclops.
+/// </summary>
+public sealed partial class CyclopsSonarButton_Update_Patch : NitroxPatch, IDynamicPatch
+{
+    public static readonly MethodInfo TARGET_METHOD = Reflect.Method((CyclopsSonarButton t) => t.Update());
+
+    internal static readonly OpCode INJECTION_OPCODE = OpCodes.Ldsfld;
+    internal static readonly object INJECTION_OPERAND = Reflect.Field(() => Player.main);
+
+    public static IEnumerable<CodeInstruction> Transpiler(MethodBase methodBase, IEnumerable<CodeInstruction> instructions, ILGenerator il)
+    {
+        /* Normally in the Update()
+         * if (Player.main.GetMode() == Player.Mode.Normal && this.sonarActive)
+         * {
+         *     this.TurnOffSonar();
+         * }
+         * this part will be changed into:
+         * if (CyclopsSonarButton_Update_Patch.ShouldTurnOff(this) && Player.main.GetMode() == Player.Mode.Normal && this.sonarActive)
+         */
+        List<CodeInstruction> codeInstructions = new(instructions);
+        Label brLabel = il.DefineLabel();
+        CodeInstruction loadInstruction = new(OpCodes.Ldarg_0);
+        CodeInstruction callInstruction = new(OpCodes.Call, Reflect.Method(() => ShouldTurnoff(default)));
+        CodeInstruction brInstruction = new(OpCodes.Brfalse, brLabel);
+        codeInstructions.Last().labels.Add(brLabel);
+
+        for (int i = 0; i < codeInstructions.Count; i++)
+        {
+            CodeInstruction instruction = codeInstructions[i];
+
+            if (instruction.opcode.Equals(INJECTION_OPCODE) && instruction.operand.Equals(INJECTION_OPERAND))
+            {
+                // The second line after the current instruction should be a Brtrue, we need its operand to have the same jump label for our brfalse
+                CodeInstruction nextBr = codeInstructions[i + 2];
+
+                // The new instruction will be the first of the if statement, so it should take the jump labels that the former first part of the statement had
+                instruction.MoveLabelsTo(loadInstruction);
+
+                yield return loadInstruction;
+                yield return callInstruction;
+                yield return brInstruction;
+            }
+            yield return instruction;
+        }
+    }
+
+    /// <returns>true (sonar should be turned off) if local player is simulating the cyclops (there's no replicator in this case)</returns>
+    public static bool ShouldTurnoff(CyclopsSonarButton cyclopsSonarButton)
+    {
+        return !cyclopsSonarButton.subRoot.GetComponent<CyclopsMovementReplicator>();
+    }
+}