feat: tomodachi life data decrypting and fix hair color rendering

src/app/api/submit/route.ts

@@ -11,6 +11,7 @@ import { MII_DECRYPTION_KEY } from "@/lib/constants";
 import { nameSchema, tagsSchema } from "@/lib/schemas";
 
 import Mii from "@/utils/mii.js/mii";
+import TomodachiLifeMii from "@/utils/tomodachi-life-mii";
 
 const uploadsDirectory = path.join(process.cwd(), "public", "uploads");
 
@@ -61,6 +62,13 @@ export async function POST(request: Request) {
 	// Convert to Mii class
 	const buffer = Buffer.from(result);
 	const mii = new Mii(buffer);
+	const tomodachiLifeMii = TomodachiLifeMii.fromBytes(qrBytes);
+
+	if (tomodachiLifeMii.hairDyeEnabled) {
+		mii.hairColor = tomodachiLifeMii.studioHairColor;
+		mii.eyebrowColor = tomodachiLifeMii.studioHairColor;
+		mii.facialHairColor = tomodachiLifeMii.studioHairColor;
+	}
 
 	// Create Mii in database
 	const miiRecord = await prisma.mii.create({

src/app/components/submit-form.tsx

@@ -13,6 +13,7 @@ import { MII_DECRYPTION_KEY } from "@/lib/constants";
 import { nameSchema, tagsSchema } from "@/lib/schemas";
 
 import Mii from "@/utils/mii.js/mii";
+import TomodachiLifeMii from "@/utils/tomodachi-life-mii";
 
 import TagSelector from "./submit/tag-selector";
 import QrUpload from "./submit/qr-upload";
@@ -107,9 +108,16 @@ export default function SubmitForm() {
 				return;
 			}
 
-			// Convert to Mii class
+			// Convert to Mii classes
 			const buffer = Buffer.from(result);
 			const mii = new Mii(buffer);
+			const tomodachiLifeMii = TomodachiLifeMii.fromBytes(qrBytes);
+
+			if (tomodachiLifeMii.hairDyeEnabled) {
+				mii.hairColor = tomodachiLifeMii.studioHairColor;
+				mii.eyebrowColor = tomodachiLifeMii.studioHairColor;
+				mii.facialHairColor = tomodachiLifeMii.studioHairColor;
+			}
 
 			try {
 				setStudioUrl(mii.studioUrl({ width: 128 }));

src/lib/constants.ts

@@ -1 +1,4 @@
 export const MII_DECRYPTION_KEY = new Uint8Array([0x59, 0xfc, 0x81, 0x7e, 0x64, 0x46, 0xea, 0x61, 0x90, 0x34, 0x7b, 0x20, 0xe9, 0xbd, 0xce, 0x52]);
+export const TOMODACHI_LIFE_DECRYPTION_KEY = new Uint8Array([
+	0x30, 0x81, 0x9f, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01,
+]);

src/utils/tomodachi-life-mii.ts

@@ -0,0 +1,87 @@
+import { TOMODACHI_LIFE_DECRYPTION_KEY } from "@/lib/constants";
+import { AES_CTR } from "@trafficlunar/asmcrypto.js";
+
+// Converts hair dye to studio color
+// (Credits to kat21)
+const hairDyeConverter = [
+	55, 51, 50, 12, 16, 12, 67, 61, 51, 64, 69, 66, 65, 86, 85, 93, 92, 19, 20, 20, 15, 32, 35, 26, 38, 41, 43, 18, 95, 97, 97, 99,
+];
+
+// (Credits to ariankordi for the byte locations)
+export default class TomodachiLifeMii {
+	firstName: string;
+	lastName: string;
+	islandName: string;
+
+	hairDye: number;
+	hairDyeEnabled: boolean;
+
+	// There is more properties but I don't plan to add them *yet*
+
+	// Property below is not located in the bytes
+	studioHairColor: number;
+
+	constructor(buffer: ArrayBuffer) {
+		const view = new DataView(buffer);
+		let offset = 0;
+
+		this.firstName = this.readUtf16String(buffer, offset, 32);
+		offset += 32;
+		this.lastName = this.readUtf16String(buffer, offset, 32);
+		offset += 32;
+
+		// Skip 3 unknown bytes
+		offset += 3;
+
+		// Read bit fields
+		const bitField = view.getUint8(offset++);
+		this.hairDyeEnabled = (bitField & 0x80) !== 0;
+		this.hairDye = (bitField & 0x3e) >> 1;
+
+		// Skip 12 unknown bytes
+		offset += 12;
+
+		// Skip catchphrase
+		offset += 32;
+
+		// Skip 58 unknown bytes
+		offset += 58;
+
+		// Skip voice properties
+		offset += 6;
+
+		// Skip character properties
+		offset += 5;
+
+		// Skip 35 unknown bytes
+		offset += 35;
+
+		this.islandName = this.readUtf16String(buffer, offset, 20);
+
+		// Convert hair dye color to studio color
+		this.studioHairColor = hairDyeConverter[this.hairDye];
+	}
+
+	static fromBytes(bytes: Uint8Array): TomodachiLifeMii {
+		const iv = bytes.slice(0x70, 128);
+		const encryptedExtraData = bytes.slice(128, -4);
+		const decryptedExtraData = AES_CTR.decrypt(encryptedExtraData, TOMODACHI_LIFE_DECRYPTION_KEY, iv);
+		const data = new Uint8Array(decryptedExtraData);
+
+		return new TomodachiLifeMii(data.buffer);
+	}
+
+	private readUtf16String(buffer: ArrayBuffer, offset: number, byteLength: number): string {
+		const bytes = new Uint8Array(buffer, offset, byteLength);
+		let str = "";
+
+		// We process every 2 bytes (UTF-16)
+		for (let i = 0; i < bytes.length; i += 2) {
+			const charCode = bytes[i] | (bytes[i + 1] << 8);
+			if (charCode === 0) break; // Stop at the null terminator (0x0000)
+			str += String.fromCharCode(charCode);
+		}
+
+		return str;
+	}
+}