Ugh... I'm not sure if I want to do this.

build.gradle

@@ -19,6 +19,8 @@ base {
 apply from: "https://raw.githubusercontent.com/constellation-mc/artifacts/main/artifacts.groovy"
 constellationRepo(project, "dark-matter")
 
+apply from: "gradle/mappings.gradle"
+
 repositories {
     maven { url 'https://jitpack.io' }
 }

gradle/mappings.gradle

@@ -0,0 +1,65 @@
+buildscript {
+    repositories {
+        mavenCentral()
+        maven {
+            name = 'Fabric'
+            url = 'https://maven.fabricmc.net/'
+        }
+    }
+
+    dependencies {
+        classpath ("net.fabricmc:mapping-io:${project.mappingio_version}")
+        classpath ('com.google.code.gson:gson:2.10.1')
+    }
+}
+
+
+import com.google.gson.JsonElement
+import com.google.gson.JsonObject
+import com.google.gson.JsonParser
+import net.fabricmc.mappingio.MappingReader
+import net.fabricmc.mappingio.MappingWriter
+import net.fabricmc.mappingio.adapter.MappingSourceNsSwitch
+import net.fabricmc.mappingio.format.MappingFormat
+import net.fabricmc.mappingio.tree.MemoryMappingTree
+
+import java.nio.file.Files
+import java.util.zip.DeflaterOutputStream
+
+ext.MANIFEST_URL = new URL("https://launchermeta.mojang.com/mc/game/version_manifest_v2.json")
+
+tasks.register("downloadCommanderMappings") {
+    File processed = new File("${project.layout.projectDirectory.getAsFile()}/.gradle/downloadCommanderMappings/${project.minecraft_version}/processed.bin")
+    if (!processed.exists()) {
+        Files.createDirectories(processed.toPath().getParent())
+
+        MemoryMappingTree tree = new MemoryMappingTree()
+        MappingReader.read(new InputStreamReader(new URL(getManifest().getAsJsonObject("downloads").getAsJsonObject("client_mappings").get("url").getAsString()).openStream()), new MappingSourceNsSwitch(tree, "target", true))
+        tree.setSrcNamespace("official")
+        tree.setDstNamespaces(List.of("mojang"))
+
+        OutputStream stream = Files.newOutputStream(processed.toPath())
+        tree.accept(MappingWriter.create(new OutputStreamWriter(new DeflaterOutputStream(stream)), MappingFormat.TINY_FILE))
+    }
+}
+
+processResources {
+    mustRunAfter(tasks.downloadCommanderMappings)
+    from(new File("${project.layout.projectDirectory.getAsFile()}/.gradle/downloadCommanderMappings/${project.minecraft_version}/processed.bin")) {
+        rename { "commander/mappings/processed.bin" }
+    }
+}
+
+JsonObject getManifest() {
+    var o = downloadObject(ext.MANIFEST_URL)
+    for (JsonElement versions : o.getAsJsonArray("versions")) {
+        if (project.minecraft_version == versions.getAsJsonObject().get("id").getAsString()) {
+            return downloadObject(new URL(versions.getAsJsonObject().get("url").getAsString()))
+        }
+    }
+    throw new IllegalStateException("Unknown version '%s'".formatted(project.minecraft_version))
+}
+
+static JsonObject downloadObject(URL url) {
+    return JsonParser.parseReader(new InputStreamReader(url.openStream())).getAsJsonObject()
+}

src/main/java/me/melontini/commander/impl/Commander.java

@@ -1,7 +1,5 @@
 package me.melontini.commander.impl;
 
-import com.google.gson.JsonObject;
-import com.google.gson.JsonParser;
 import lombok.Getter;
 import lombok.extern.log4j.Log4j2;
 import me.melontini.commander.api.expression.Arithmetica;
@@ -15,7 +13,6 @@
 import me.melontini.commander.impl.util.loot.ExpressionLootCondition;
 import me.melontini.commander.impl.util.mappings.AmbiguousRemapper;
 import me.melontini.commander.impl.util.mappings.MappingKeeper;
-import me.melontini.commander.impl.util.mappings.MinecraftDownloader;
 import me.melontini.dark_matter.api.base.util.Exceptions;
 import me.melontini.dark_matter.api.base.util.PrependingLogger;
 import me.melontini.dark_matter.api.data.codecs.ExtraCodecs;
@@ -32,7 +29,6 @@
 import net.minecraft.util.Util;
 
 import java.io.IOException;
-import java.io.InputStreamReader;
 import java.nio.file.Files;
 import java.nio.file.LinkOption;
 import java.nio.file.Path;
@@ -48,7 +44,6 @@ public class Commander implements ModInitializer {
     public static final LootConditionType EXPRESSION_CONDITION = Registry.register(Registries.LOOT_CONDITION_TYPE, id("expression"), new LootConditionType(ExtraCodecs.toJsonSerializer(ExpressionLootCondition.CODEC)));
 
     public static final Path COMMANDER_PATH = FabricLoader.getInstance().getGameDir().resolve(".commander");
-    public static final String MINECRAFT_VERSION = getVersion();
 
     @Getter
     private static AmbiguousRemapper mappingKeeper;
@@ -73,13 +68,11 @@ public void onInitialize() {
         EvalUtils.init();
 
         try {
-            MinecraftDownloader.downloadMappings();
-
             CompletableFuture<MemoryMappingTree> offMojmap = CompletableFuture.supplyAsync(MappingKeeper::loadOffMojmap, Util.getMainWorkerExecutor());
             CompletableFuture<MemoryMappingTree> offTarget = CompletableFuture.supplyAsync(MappingKeeper::loadOffTarget, Util.getMainWorkerExecutor());
             mappingKeeper = new MappingKeeper(MappingKeeper.loadMojmapTarget(offMojmap.join(), offTarget.join()));
         } catch (Throwable t) {
-            log.error("Failed to download and prepare mappings! Data access remapping will not work!!!", t);
+            log.error("Failed to prepare mappings! Data access remapping will not work!!!", t);
             mappingKeeper = (cls, name) -> name;//Returning null will force it to traverse the hierarchy.
         }
 
@@ -94,9 +87,4 @@ public void onInitialize() {
                 DAMAGE_SOURCE, EXPLOSION_RADIUS,
                 BLOCK_STATE, BLOCK_ENTITY);
     }
-
-    private static String getVersion() {
-        JsonObject o = JsonParser.parseReader(new InputStreamReader(MinecraftDownloader.class.getResourceAsStream("/version.json"))).getAsJsonObject();
-        return o.getAsJsonPrimitive("id").getAsString();
-    }
 }

src/main/java/me/melontini/commander/impl/util/mappings/MappingKeeper.java

@@ -2,7 +2,6 @@
 
 import lombok.SneakyThrows;
 import lombok.extern.log4j.Log4j2;
-import me.melontini.commander.impl.Commander;
 import net.fabricmc.loader.api.FabricLoader;
 import net.fabricmc.mappingio.MappingReader;
 import net.fabricmc.mappingio.adapter.MappingSourceNsSwitch;
@@ -11,8 +10,10 @@
 import org.objectweb.asm.Type;
 
 import java.io.InputStreamReader;
-import java.util.List;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Objects;
+import java.util.zip.InflaterInputStream;
 
 @Log4j2
 public record MappingKeeper(MemoryMappingTree mojmapTarget) implements AmbiguousRemapper {
@@ -36,11 +37,10 @@ public static MemoryMappingTree loadMojmapTarget(MemoryMappingTree offMojmap, Me
     public static MemoryMappingTree loadOffMojmap() {
         if (NAMESPACE.equals("mojang")) return null;
         log.info("Loading official->mojmap mappings...");
+        Path path = FabricLoader.getInstance().getModContainer("commander").orElseThrow().findPath("commander/mappings/processed.bin").orElseThrow();
 
         var tree = new MemoryMappingTree();
-        MappingReader.read(Commander.COMMANDER_PATH.resolve("mappings/client_mappings.txt"), new MappingSourceNsSwitch(tree, "target"));
-        tree.setSrcNamespace("official");
-        tree.setDstNamespaces(List.of("mojang"));
+        MappingReader.read(new InputStreamReader(new InflaterInputStream(Files.newInputStream(path))), tree);
         return tree;
     }