feat(platform): add Discord onboarding and Velocity gate

packages/minecraft/src/index.ts

@@ -0,0 +1,65 @@
+const MINECRAFT_USERNAME = /^[A-Za-z0-9_]{3,16}$/;
+const MINECRAFT_UUID = /^[0-9a-f]{32}$/i;
+const DISCORD_NICKNAME_LIMIT = 32;
+
+export interface JavaProfile {
+  uuid: string;
+  username: string;
+}
+
+export async function lookupJavaProfile(
+  username: string,
+  request: typeof fetch = fetch,
+): Promise<JavaProfile | null> {
+  const candidate = username.trim();
+  if (!MINECRAFT_USERNAME.test(candidate)) return null;
+
+  const response = await request(
+    `https://api.mojang.com/users/profiles/minecraft/${encodeURIComponent(candidate)}`,
+    { headers: { accept: "application/json" }, cache: "no-store" },
+  );
+
+  if (response.status === 204 || response.status === 404) return null;
+  if (!response.ok) throw new Error(`Mojang profile lookup failed (${response.status})`);
+
+  const profile: unknown = await response.json();
+  if (!profile || typeof profile !== "object") return null;
+  const { id, name } = profile as { id?: unknown; name?: unknown };
+  if (typeof id !== "string" || !MINECRAFT_UUID.test(id)) return null;
+  if (typeof name !== "string" || !MINECRAFT_USERNAME.test(name)) return null;
+
+  return { uuid: id.toLowerCase(), username: name };
+}
+
+export function formatDiscordNickname(firstName: string, minecraftUsername: string) {
+  const suffix = ` (${minecraftUsername})`;
+  const availableCharacters = DISCORD_NICKNAME_LIMIT - [...suffix].length;
+  const shortenedName = [...firstName.trim()].slice(0, Math.max(1, availableCharacters)).join("").trimEnd();
+  return `${shortenedName}${suffix}`;
+}
+
+export async function updateGuildNickname(
+  input: {
+    guildId: string;
+    discordUserId: string;
+    nickname: string;
+    botToken: string;
+  },
+  request: typeof fetch = fetch,
+) {
+  const response = await request(
+    `https://discord.com/api/v10/guilds/${input.guildId}/members/${input.discordUserId}`,
+    {
+      method: "PATCH",
+      headers: {
+        authorization: `Bot ${input.botToken}`,
+        "content-type": "application/json",
+      },
+      body: JSON.stringify({ nick: input.nickname }),
+    },
+  );
+
+  if (!response.ok) {
+    throw new Error(`Discord nickname update failed (${response.status})`);
+  }
+}