1 files changed, 80 insertions, 0 deletions
diff --git a/src/main/kotlin/features/misc/ModAnnouncer.kt b/src/main/kotlin/features/misc/ModAnnouncer.kt
new file mode 100644
index 0000000..c2aa013
--- /dev/null
+++ b/src/main/kotlin/features/misc/ModAnnouncer.kt
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+package moe.nea.firmament.features.misc
+
+import io.netty.buffer.ByteBuf
+import net.fabricmc.fabric.api.networking.v1.PacketByteBufs
+import net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry
+import net.fabricmc.loader.api.FabricLoader
+import net.minecraft.network.codec.StreamCodec
+import net.minecraft.network.codec.ByteBufCodecs
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload
+import net.minecraft.network.protocol.common.ServerboundCustomPayloadPacket
+import moe.nea.firmament.Firmament
+import moe.nea.firmament.annotations.Subscribe
+import moe.nea.firmament.events.JoinServerEvent
+
+/**
+ * This is a class that announces all mods to hypixel (or any other server you connect to).
+ *
+ * I don't mind cheat mods, i just think they should be honest about themselves.
+ *
+ * If you are a cheat mod (or think you could possibly be seen as one), you have two options:
+ *
+ * - risk getting your users banned from hypixel by exposing your modid + version number in a packet sent on first connect
+ * - hide yourself from this list by either a mixin, or (more easily) by specifying a tag in your fabric.mod.json:
+ *
+ * ```json
+ * {
+ *   "schemaVersion": 1,
+ *   "id": "my-cheat-mod",
+ *   "custom": { "firmament:hide_from_modlist": true }
+ * }
+ * ```
+ */
+object ModAnnouncer {
+
+	data class ModEntry(
+		val modid: String,
+		val modVersion: String,
+	) {
+		companion object {
+			val CODEC: StreamCodec<ByteBuf, ModEntry> = StreamCodec.composite(
+				ByteBufCodecs.STRING_UTF8, ModEntry::modid,
+				ByteBufCodecs.STRING_UTF8, ModEntry::modVersion,
+				::ModEntry
+			)
+		}
+	}
+
+	data class ModPacket(
+		val mods: List<ModEntry>,
+	) : CustomPacketPayload {
+		override fun type(): CustomPacketPayload.Type<out ModPacket> {
+			return ID
+		}
+
+		companion object {
+			val ID = CustomPacketPayload.Type<ModPacket>(Firmament.identifier("mod_list"))
+			val CODEC: StreamCodec<ByteBuf, ModPacket> = ModEntry.CODEC.apply(ByteBufCodecs.list())
+				.map(::ModPacket, ModPacket::mods)
+		}
+	}
+
+	@Subscribe
+	fun onServerJoin(event: JoinServerEvent) {
+		val packet = ModPacket(
+			FabricLoader.getInstance()
+				.allMods
+				.filter { !it.metadata.containsCustomValue("firmament:hide_from_modlist") }
+				.map { ModEntry(it.metadata.id, it.metadata.version.friendlyString) })
+		val pbb = PacketByteBufs.create()
+		ModPacket.CODEC.encode(pbb, packet)
+		if (pbb.writerIndex() > ServerboundCustomPayloadPacket.MAX_PAYLOAD_SIZE)
+			return
+
+		event.networkHandler.send(event.packetSender.createPacket(packet))
+	}
+
+	init {
+		PayloadTypeRegistry.playC2S().register(ModPacket.ID, ModPacket.CODEC)
+	}
+}