Added translation system.

src/main/java/com/koralix/oneforall/lang/Language.java

@@ -0,0 +1,74 @@
+package com.koralix.oneforall.lang;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.koralix.oneforall.OneForAll;
+
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+import static net.minecraft.datafixer.fix.BlockEntitySignTextStrictJsonFix.GSON;
+
+public enum Language {
+    SPANISH("es_es"),
+    GALICIAN("gl_es");
+
+    private static final Map<String, Language> LANGUAGES;
+
+    static {
+        Map<String, Language> languages = new HashMap<>();
+        for (Language language : values()) {
+            languages.put(language.code, language);
+        }
+        LANGUAGES = Map.copyOf(languages);
+    }
+
+    private final String code;
+    private final Map<String, String> translations;
+
+    Language(String code) throws IllegalArgumentException {
+        this.code = code;
+
+        OneForAll.getInstance().getLogger().info("Loading translations from {}", code);
+
+        Map<String, String> translationMap = new HashMap<>();
+        String languageFile = "/assets/oneforall/lang/" + code + ".json";
+
+        try (InputStream inputStream = TranslationUnit.class.getResourceAsStream(languageFile)) {
+            JsonObject jsonObject = GSON.fromJson(new InputStreamReader(inputStream, StandardCharsets.UTF_8), JsonObject.class);
+
+            for (Map.Entry<String, JsonElement> entry : jsonObject.entrySet()) {
+                translationMap.put(entry.getKey(), entry.getValue().getAsString());
+            }
+
+            this.translations = Map.copyOf(translationMap);
+        } catch (Exception e) {
+            throw new IllegalArgumentException("Failed to load translations from " + code, e);
+        }
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public boolean containsKey(String code) {
+        return translations.containsKey(code);
+    }
+
+    public Optional<String> translate(String code) {
+        return Optional.ofNullable(translations.get(code));
+    }
+
+    @Override
+    public String toString() {
+        return code;
+    }
+
+    public static Language fromCode(String s) {
+        return LANGUAGES.get(s);
+    }
+}

src/main/java/com/koralix/oneforall/lang/TranslationUnit.java

@@ -0,0 +1,65 @@
+package com.koralix.oneforall.lang;
+
+import com.koralix.oneforall.network.ClientSession;
+import com.koralix.oneforall.network.ServerLoginManager;
+import com.koralix.oneforall.settings.ServerSettings;
+import net.minecraft.text.MutableText;
+import net.minecraft.text.Text;
+import net.minecraft.text.TranslatableTextContent;
+
+import java.util.ListIterator;
+import java.util.Optional;
+import java.util.UUID;
+
+public class TranslationUnit {
+    private final static Language DEFAULT_LANGUAGE = Language.SPANISH;
+    private static Optional<UUID> TARGET_PLAYER = Optional.empty();
+
+    public static String translate(Language lang, String code) {
+        return lang.translate(code)
+                .or(() -> ServerSettings.DEFAULT_LANGUAGE.value().translate(code))
+                .or(() -> DEFAULT_LANGUAGE.translate(code))
+                .orElse(code);
+    }
+
+    public static void prepare(UUID uuid) {
+        TARGET_PLAYER = Optional.of(uuid);
+    }
+
+    public static Text adaptText(Text text) {
+        Text result = text;
+
+        ClientSession session = null;
+        if (TARGET_PLAYER.isPresent()) {
+            session = ServerLoginManager.SESSIONS.get(TARGET_PLAYER.get());
+        }
+
+        if (session != null && session.modVersion() != null) { // TODO: Version dependent translations
+            return result;
+        }
+
+        if (!text.getSiblings().isEmpty()) {
+            ListIterator<Text> iterator = text.getSiblings().listIterator();
+
+            while (iterator.hasNext()) {
+                iterator.set(adaptText(iterator.next()));
+            }
+        }
+
+        if (text.getContent() instanceof TranslatableTextContent textContent) {
+            String key = textContent.getKey();
+            Language userLanguage = session == null
+                    ? ServerSettings.DEFAULT_LANGUAGE.value()
+                    : (session.language() != null ? session.language() : ServerSettings.DEFAULT_LANGUAGE.value());
+            String translation = translate(userLanguage, key);
+            MutableText content = Text.translatableWithFallback(key, translation);
+            for (Text sibling: text.getSiblings()) {
+                content.append(sibling);
+            }
+            result = content;
+        }
+
+        return result;
+    }
+
+}

src/main/java/com/koralix/oneforall/mixin/fapi/FixServerLoginNetworkAddonRegisterReceiver.java → src/main/java/com/koralix/oneforall/mixin/server/fapi/FixServerLoginNetworkAddonRegisterReceiver.java

@@ -1,4 +1,4 @@
-package com.koralix.oneforall.mixin.fapi;
+package com.koralix.oneforall.mixin.server.fapi;
 
 import net.fabricmc.fabric.impl.networking.GlobalReceiverRegistry;
 import net.fabricmc.fabric.impl.networking.server.ServerLoginNetworkAddon;

src/main/java/com/koralix/oneforall/mixin/server/protocol/ClientConnectionMixin.java

@@ -0,0 +1,22 @@
+package com.koralix.oneforall.mixin.server.protocol;
+
+import com.koralix.oneforall.network.ClientSession;
+import com.koralix.oneforall.network.ClientSessionWrapper;
+import net.minecraft.network.ClientConnection;
+import org.spongepowered.asm.mixin.Mixin;
+
+@Mixin(ClientConnection.class)
+public class ClientConnectionMixin implements ClientSessionWrapper {
+    private ClientSession session;
+
+    @Override
+    public ClientSession session() {
+        return session;
+    }
+
+    @Override
+    public void session(ClientSession session) {
+        this.session = session;
+    }
+
+}

src/main/java/com/koralix/oneforall/mixin/server/protocol/PacketByteBufMixin.java

@@ -0,0 +1,23 @@
+package com.koralix.oneforall.mixin.server.protocol;
+
+import com.koralix.oneforall.lang.TranslationUnit;
+import net.minecraft.network.PacketByteBuf;
+import net.minecraft.text.Text;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.ModifyArg;
+
+@Mixin(PacketByteBuf.class)
+public class PacketByteBufMixin {
+    @ModifyArg(
+            method = "Lnet/minecraft/network/PacketByteBuf;writeText(Lnet/minecraft/text/Text;)Lnet/minecraft/network/PacketByteBuf;",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lnet/minecraft/text/Text$Serializer;toJson(Lnet/minecraft/text/Text;)Ljava/lang/String;"
+            ),
+            index = 0
+    )
+    private Text writeTextInjector(Text text) {
+        return TranslationUnit.adaptText(text);
+    }
+}

src/main/java/com/koralix/oneforall/mixin/server/protocol/ServerLoginNetworkHandlerMixin.java

@@ -0,0 +1,28 @@
+package com.koralix.oneforall.mixin.server.protocol;
+
+import com.koralix.oneforall.network.ClientSession;
+import com.koralix.oneforall.network.ClientSessionWrapper;
+import net.minecraft.network.ClientConnection;
+import net.minecraft.server.network.ServerLoginNetworkHandler;
+import org.jetbrains.annotations.NotNull;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import java.util.Objects;
+
+@Mixin(ServerLoginNetworkHandler.class)
+public class ServerLoginNetworkHandlerMixin implements ClientSessionWrapper {
+    @Shadow private ClientConnection connection;
+
+    @Override
+    public ClientSession session() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void session(@NotNull ClientSession session) {
+        ClientSessionWrapper modConnection = (ClientSessionWrapper) Objects.requireNonNull(connection);
+
+        modConnection.session(session);
+    }
+}

src/main/java/com/koralix/oneforall/mixin/server/protocol/ServerPlayNetworkHandlerMixin.java

@@ -0,0 +1,55 @@
+package com.koralix.oneforall.mixin.server.protocol;
+
+import com.koralix.oneforall.lang.TranslationUnit;
+import com.koralix.oneforall.network.ActOnPlayPacketAction;
+import com.koralix.oneforall.network.ActOnPlayPacketHandler;
+import com.koralix.oneforall.network.ClientSession;
+import com.koralix.oneforall.network.ClientSessionWrapper;
+import net.minecraft.network.ClientConnection;
+import net.minecraft.network.PacketCallbacks;
+import net.minecraft.network.packet.Packet;
+import net.minecraft.network.packet.c2s.play.ClientSettingsC2SPacket;
+import net.minecraft.server.network.ServerPlayNetworkHandler;
+import net.minecraft.server.network.ServerPlayerEntity;
+import org.jetbrains.annotations.Nullable;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(ServerPlayNetworkHandler.class)
+public class ServerPlayNetworkHandlerMixin implements ClientSessionWrapper {
+    @Shadow
+    ServerPlayerEntity player;
+    @Shadow
+    ClientConnection connection;
+
+    @Inject(
+            method = "Lnet/minecraft/server/network/ServerPlayNetworkHandler;sendPacket(Lnet/minecraft/network/packet/Packet;Lnet/minecraft/network/PacketCallbacks;)V",
+            at = @At("HEAD")
+    )
+    private void setTranslationTargetUUID(Packet<?> packet, @Nullable PacketCallbacks callbacks, CallbackInfo ci) {
+        TranslationUnit.prepare(player.getUuid());
+    }
+
+    @Override
+    public ClientSession session() {
+        return ((ClientSessionWrapper) connection).session();
+    }
+
+    @Override
+    public void session(ClientSession session) {
+        ((ClientSessionWrapper) connection).session(session);
+    }
+
+    @Inject(
+            method = "Lnet/minecraft/server/network/ServerPlayNetworkHandler;onClientSettings(Lnet/minecraft/network/packet/c2s/play/ClientSettingsC2SPacket;)V",
+            at = @At("HEAD")
+    )
+    private void onClientSettings(ClientSettingsC2SPacket packet, CallbackInfo ci) {
+        for (ActOnPlayPacketAction<ClientSettingsC2SPacket> action: ActOnPlayPacketHandler.getActionsFor(this.session(), ClientSettingsC2SPacket.class)) {
+            action.execute(connection, player, packet);
+        }
+    }
+}

src/main/java/com/koralix/oneforall/network/ActOnPlayPacketAction.java

@@ -0,0 +1,10 @@
+package com.koralix.oneforall.network;
+
+import net.minecraft.network.ClientConnection;
+import net.minecraft.network.packet.Packet;
+import net.minecraft.server.network.ServerPlayerEntity;
+
+@FunctionalInterface
+public interface ActOnPlayPacketAction<T extends Packet<?>>  {
+    void execute(ClientConnection connection, ServerPlayerEntity player, T packet);
+}

src/main/java/com/koralix/oneforall/network/ActOnPlayPacketHandler.java

@@ -0,0 +1,27 @@
+package com.koralix.oneforall.network;
+
+import net.minecraft.network.packet.Packet;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class ActOnPlayPacketHandler {
+    private static final Map<ClientSession, Map<Class<Packet<?>>, List<ActOnPlayPacketAction<?>>>> REGISTRY = new HashMap<>();
+
+    public static <T extends Packet<?>> void register(Class<T> clazz, ClientSession session, ActOnPlayPacketAction<T> action) {
+        if (!REGISTRY.containsKey(session)) REGISTRY.put(session, new HashMap<>());
+        if (!REGISTRY.get(session).containsKey(clazz)) REGISTRY.get(session).put((Class<Packet<?>>) clazz, new ArrayList<>());
+
+        REGISTRY.get(session).get(clazz).add(action);
+    }
+
+    public static <T extends Packet<?>> List<ActOnPlayPacketAction<T>> getActionsFor(ClientSession session, Class<T> clazz) {
+        if (REGISTRY.containsKey(session) && REGISTRY.get(session).containsKey(clazz)) {
+            // This cast should be safe since T extends Packet<?>
+            return (List<ActOnPlayPacketAction<T>>)(Object)REGISTRY.get(session).get(clazz);
+        }
+        return new ArrayList<>();
+    }
+}

src/main/java/com/koralix/oneforall/network/ClientSession.java

@@ -0,0 +1,32 @@
+package com.koralix.oneforall.network;
+
+import com.koralix.oneforall.lang.Language;
+
+public class ClientSession {
+    private Language language;
+    private String modVersion;
+
+    public Language language() {
+        return language;
+    }
+
+    public void language(Language language) {
+        this.language = language;
+    }
+
+    public String modVersion() {
+        return modVersion;
+    }
+
+    public void modVersion(String modVersion) {
+        this.modVersion = modVersion;
+    }
+
+    @Override
+    public String toString() {
+        return "ClientSession{" +
+                "language='" + language + '\'' +
+                ", modVersion='" + modVersion + '\'' +
+                '}';
+    }
+}

src/main/java/com/koralix/oneforall/network/ClientSessionWrapper.java

@@ -0,0 +1,6 @@
+package com.koralix.oneforall.network;
+
+public interface ClientSessionWrapper {
+    ClientSession session();
+    void session(ClientSession session);
+}