refactor: switch to using a tweaker

versions/build.gradle.kts

@@ -12,8 +12,7 @@ plugins {
     `java-library`
 }
 
-val tweakClass = "org.spongepowered.asm.launch.MixinTweaker"
-val transformerPlugin = "org.polyfrost.spice.platform.impl.forge.asm.TransformerPlugin"
+val tweakClass = "org.polyfrost.spice.platform.impl.forge.asm.SpiceTweaker"
 
 base.archivesName = "Spice-${platform}"
 
@@ -26,7 +25,6 @@ loom {
     runConfigs {
         "client" {
             if (project.platform.isLegacyForge) {
-                property("fml.coreMods.load", transformerPlugin)
                 programArgs("--tweakClass", tweakClass)
             }
             property("mixin.debug.export", "true")
@@ -104,8 +102,6 @@ tasks {
         if (platform.isLegacyForge) {
             manifest {
                 attributes += mapOf(
-                    "FMLCorePluginContainsFMLMod" to "Yes, yes it does",
-                    "FMLCorePlugin" to transformerPlugin,
                     "ModSide" to "CLIENT",
                     "ForceLoadAsMod" to true,
                     "TweakOrder" to "0",

versions/src/main/kotlin/org/polyfrost/spice/platform/impl/forge/asm/ClassTransformer.kt

@@ -2,7 +2,7 @@ package org.polyfrost.spice.platform.impl.forge.asm
 //#if FORGE
 
 import com.google.common.base.Stopwatch
-import net.minecraft.launchwrapper.LaunchClassLoader
+import net.minecraft.launchwrapper.Launch
 import net.minecraft.launchwrapper.LogWrapper
 import org.apache.logging.log4j.LogManager
 import org.objectweb.asm.ClassReader
@@ -29,14 +29,7 @@ class ClassTransformer : LaunchTransformer, Transformer {
 
     private val transformerCache: Map<String, ByteArray>
 
-    private val loader =
-        ClassTransformer::class.java
-            .classLoader
-            .let {
-                assert(it is LaunchClassLoader) { "Class loader isn't LaunchClassLoader..?" }
-
-                it as LaunchClassLoader
-            }
+    private val loader = Launch.classLoader
 
     private val logger = LogManager.getLogger("Spice/Forge/Transformer")
     private val transformers = mutableListOf<IClassTransformer>()

versions/src/main/kotlin/org/polyfrost/spice/platform/impl/forge/asm/SpiceTweaker.kt

@@ -0,0 +1,56 @@
+package org.polyfrost.spice.platform.impl.forge.asm
+//#if FORGE
+
+import net.minecraft.launchwrapper.ITweaker
+import net.minecraft.launchwrapper.Launch
+import net.minecraft.launchwrapper.LaunchClassLoader
+import org.spongepowered.asm.launch.MixinBootstrap
+import org.spongepowered.asm.mixin.Mixins
+import java.io.File
+
+
+class SpiceTweaker : ITweaker {
+    private val mixinTweaker: String = "org.spongepowered.asm.launch.MixinTweaker"
+
+    init {
+        injectMixinTweaker()
+    }
+
+    override fun acceptOptions(args: MutableList<String>, gameDir: File?, assetsDir: File?, profile: String?) {
+
+    }
+
+    override fun injectIntoClassLoader(classLoader: LaunchClassLoader) {
+        MixinBootstrap.init()
+        Mixins.addConfiguration("spice.mixins.json")
+
+        Launch.classLoader.registerTransformer(ClassTransformer::class.java.name)
+    }
+
+    override fun getLaunchTarget(): String? = null
+    override fun getLaunchArguments(): Array<String> = arrayOf()
+
+    @Suppress("UNCHECKED_CAST")
+    @Throws(ClassNotFoundException::class, IllegalAccessException::class, InstantiationException::class)
+    private fun injectMixinTweaker() {
+        val tweakClasses = Launch.blackboard["TweakClasses"]!! as List<String>
+
+        if (tweakClasses.contains(mixinTweaker)) {
+            initMixinTweaker()
+            return
+        }
+
+        if (Launch.blackboard["mixin.initialised"] != null) return
+
+        (Launch.blackboard["Tweaks"]!! as MutableList<ITweaker>).add(initMixinTweaker())
+    }
+
+    @Throws(ClassNotFoundException::class, IllegalAccessException::class, InstantiationException::class)
+    private fun initMixinTweaker(): ITweaker {
+        Launch.classLoader.addClassLoaderExclusion(mixinTweaker.substring(0, mixinTweaker.lastIndexOf(".")))
+
+        return Class.forName(mixinTweaker, true, Launch.classLoader).newInstance() as ITweaker
+    }
+}
+
+//#endif