From 2745fa36dbe5b6bf31f026121283312f3d47f0c9 Mon Sep 17 00:00:00 2001
From: Soar Qin <soarchin@gmail.com>
Date: Fri, 10 Feb 2023 03:04:51 +0800
Subject: [PATCH] WIP for MechaDronesTweaks

---
 MechaDronesTweaks/MechaDronesTweaks.cs | 135 ++++++++++++++++++++++++-
 1 file changed, 132 insertions(+), 3 deletions(-)

diff --git a/MechaDronesTweaks/MechaDronesTweaks.cs b/MechaDronesTweaks/MechaDronesTweaks.cs
index 4d7e42d..ad01d3a 100644
--- a/MechaDronesTweaks/MechaDronesTweaks.cs
+++ b/MechaDronesTweaks/MechaDronesTweaks.cs
@@ -1,5 +1,8 @@
 using System;
+using System.Collections.Generic;
+using System.Reflection.Emit;
 using BepInEx;
+using BepInEx.Configuration;
 using HarmonyLib;
 
 namespace MechaDronesTweaks;
@@ -8,12 +11,17 @@ namespace MechaDronesTweaks;
 [BepInDependency(FastDronesRemover.FastDronesGuid, BepInDependency.DependencyFlags.SoftDependency)]
 public class MechaDronesTweaksPlugin : BaseUnityPlugin
 {
+    public new static readonly BepInEx.Logging.ManualLogSource Logger =
+        BepInEx.Logging.Logger.CreateLogSource(PluginInfo.PLUGIN_NAME);
+
+    private readonly Harmony _harmony = new(PluginInfo.PLUGIN_GUID);
+
     public MechaDronesTweaksPlugin()
     {
-        var harmony = new Harmony(PluginInfo.PLUGIN_GUID);
         /* Remove FastDrones MOD if loaded */
-        try {
-            if (FastDronesRemover.Run(harmony))
+        try
+        {
+            if (FastDronesRemover.Run(_harmony))
             {
                 Logger.LogInfo("Unpatch FastDrones - OK");
             }
@@ -23,4 +31,125 @@ public class MechaDronesTweaksPlugin : BaseUnityPlugin
             Logger.LogWarning($"Failed to unpatch FastDrones: {e}");
         }
     }
+
+    public void Awake()
+    {
+        MechaDronesTweaks.UseFixedSpeed = Config.Bind("MechaDrones", "UseFixedSpeed", MechaDronesTweaks.UseFixedSpeed,
+            "Use fixed speed for mecha drones").Value;
+        MechaDronesTweaks.RemoveSpeedLimitForStage1 = Config.Bind("MechaDrones", "RemoveSpeedLimitForStage1",
+            MechaDronesTweaks.RemoveSpeedLimitForStage1,
+            "Remove speed limit for 1st stage (flying away from mecha in ~1/3 speed for several frames)").Value;
+        MechaDronesTweaks.FixedSpeed = Config.Bind("MechaDrones", "FixedSpeed", MechaDronesTweaks.FixedSpeed,
+            new ConfigDescription("Fixed speed for mecha drones, working only when UseFixedSpeed is enabled",
+                new AcceptableValueRange<float>(6f, 1000f))).Value;
+        MechaDronesTweaks.SpeedMultiplier = Config.Bind("MechaDrones", "SpeedMultiplier",
+            MechaDronesTweaks.SpeedMultiplier,
+            new ConfigDescription("Speed multiplier for mecha drones, working only when UseFixedSpeed is disabled",
+                new AcceptableValueRange<float>(1f, 10f))).Value;
+        MechaDronesTweaks.EnergyMultiplier = Config.Bind("MechaDrones", "EnergyMultiplier",
+            MechaDronesTweaks.EnergyMultiplier,
+            new ConfigDescription("Energy consumption multiplier for mecha drones",
+                new AcceptableValueRange<float>(0.01f, 1f))).Value;
+
+        _harmony.PatchAll(typeof(MechaDronesTweaks));
+    }
 }
+
+[HarmonyPatch]
+public static class MechaDronesTweaks
+{
+    public static bool UseFixedSpeed = false;
+    public static bool RemoveSpeedLimitForStage1 = true;
+    public static float FixedSpeed = 500f;
+    public static float SpeedMultiplier = 5f;
+    public static float EnergyMultiplier = 0.1f;
+
+    [HarmonyTranspiler, HarmonyPatch(typeof(MechaDroneLogic), "UpdateDrones")]
+    private static IEnumerable<CodeInstruction> MechaUpdateDrones_Transpiler(IEnumerable<CodeInstruction> instructions)
+    {
+        foreach (var instr in instructions)
+        {
+            yield return instr;
+            if (instr.opcode == OpCodes.Ldfld && instr.OperandIs(AccessTools.Field(typeof(Mecha), "droneEnergyPerMeter")))
+            {
+                yield return new CodeInstruction(OpCodes.Ldc_R8, (double)EnergyMultiplier);
+                yield return new CodeInstruction(OpCodes.Mul);
+            }
+        }
+    }
+
+    [HarmonyTranspiler, HarmonyPatch(typeof(MechaDrone), "Update")]
+    private static IEnumerable<CodeInstruction> MechaDroneUpdate_Transpiler(IEnumerable<CodeInstruction> instructions)
+    {
+        var lastIsLdarg0 = false;
+        CodeInstruction lastInstr = null;
+        foreach (var instr in instructions)
+        {
+            if (instr.opcode == OpCodes.Ldarg_0)
+            {
+                if (lastIsLdarg0)
+                {
+                    yield return lastInstr;
+                    continue;
+                }
+
+                lastIsLdarg0 = true;
+                lastInstr = instr;
+                continue;
+            }
+
+            if (lastIsLdarg0)
+            {
+                lastIsLdarg0 = false;
+                if (instr.opcode == OpCodes.Ldfld &&
+                    instr.OperandIs(AccessTools.Field(typeof(MechaDrone), "speed")))
+                {
+                    if (UseFixedSpeed)
+                    {
+                        lastInstr.opcode = OpCodes.Ldc_R4;
+                        lastInstr.operand = FixedSpeed;
+                        yield return lastInstr;
+                    }
+                    else
+                    {
+                        yield return lastInstr;
+                        yield return instr;
+                        yield return new CodeInstruction(OpCodes.Ldc_R4, SpeedMultiplier);
+                        yield return new CodeInstruction(OpCodes.Mul);
+                    }
+
+                    continue;
+                }
+
+                yield return lastInstr;
+                yield return instr;
+                continue;
+            }
+
+            if (instr.opcode == OpCodes.Ldc_R4)
+            {
+                if (instr.OperandIs(0.5f))
+                {
+                    if (FixedSpeed > 59f)
+                    {
+                        instr.operand = 0.5f * FixedSpeed / 50f;
+                        yield return instr;
+                        continue;
+                    }
+                }
+                else if (instr.OperandIs(3f))
+                {
+                    if (RemoveSpeedLimitForStage1)
+                    {
+                        instr.operand = 10000f;
+                    }
+
+                    yield return instr;
+                    continue;
+                }
+            }
+
+            yield return instr;
+        }
+    }
+}
\ No newline at end of file