fix: Use a better ID format

packages/core/src/examples.ts

@@ -1,8 +1,8 @@
-import { prefixes } from "./utils/id.js";
+import { Identifier } from "./id/index.js";
 
 export namespace Examples {
-  export const Id = (prefix: keyof typeof prefixes) =>
-    `${prefixes[prefix]}_XXXXXXXXXXXXXXXXXXXXXXXXX`;
+  export const Id = (prefix: keyof typeof Identifier.prefixes) =>
+    `${Identifier.prefixes[prefix]}_XXXXXXXXXXXXXXXXXXXXXXXXX`;
 
   export const User = {
     id: Id("user"),

packages/core/src/id/index.ts

@@ -0,0 +1,89 @@
+import { z } from "zod/v4";
+import { randomBytes } from "crypto";
+
+export namespace Identifier {
+  export const prefixes = {
+    app: "app",
+    user: "usr",
+    steam: "stm",
+    member: "mbr",
+    session: "ses",
+    apiSecret: "sec",
+    apiPersonal: "pat",
+    organisation: "org",
+  } as const;
+
+  export function schema(prefix: keyof typeof prefixes) {
+    return z.string().startsWith(prefixes[prefix]);
+  }
+
+  const LENGTH = 26;
+
+  // State for monotonic ID generation
+  let lastTimestamp = 0;
+  let counter = 0;
+
+  export function ascending(prefix: keyof typeof prefixes, given?: string) {
+    return generateID(prefix, false, given);
+  }
+
+  export function descending(prefix: keyof typeof prefixes, given?: string) {
+    return generateID(prefix, true, given);
+  }
+
+  function generateID(
+    prefix: keyof typeof prefixes,
+    descending: boolean,
+    given?: string,
+  ): string {
+    if (!given) {
+      return create(prefix, descending);
+    }
+
+    if (!given.startsWith(prefixes[prefix])) {
+      throw new Error(`ID ${given} does not start with ${prefixes[prefix]}`);
+    }
+    return given;
+  }
+
+  function randomBase62(length: number): string {
+    const chars =
+      "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+    let result = "";
+    const bytes = randomBytes(length);
+    for (let i = 0; i < length; i++) {
+      result += chars[bytes[i]! % 62];
+    }
+    return result;
+  }
+
+  export function create(
+    prefix: keyof typeof prefixes,
+    descending: boolean,
+    timestamp?: number,
+  ): string {
+    const currentTimestamp = timestamp ?? Date.now();
+
+    if (currentTimestamp !== lastTimestamp) {
+      lastTimestamp = currentTimestamp;
+      counter = 0;
+    }
+    counter++;
+
+    let now = BigInt(currentTimestamp) * BigInt(0x1000) + BigInt(counter);
+
+    now = descending ? ~now : now;
+
+    const timeBytes = Buffer.alloc(6);
+    for (let i = 0; i < 6; i++) {
+      timeBytes[i] = Number((now >> BigInt(40 - 8 * i)) & BigInt(0xff));
+    }
+
+    return (
+      prefixes[prefix] +
+      "_" +
+      timeBytes.toString("hex") +
+      randomBase62(LENGTH - 12)
+    );
+  }
+}

packages/core/src/organisation/index.ts

@@ -1,10 +1,11 @@
 import { z } from "zod/v4";
 import { Examples } from "../examples.js";
+import { Identifier } from "../id/index.js";
 
 export namespace Organisation {
   export const Info = z
     .object({
-      id: z.string().meta({
+      id: Identifier.schema("organisation").meta({
         description: "The unique identifier of the organisation",
         example: Examples.Organisation.id,
       }),

packages/core/src/steam/index.ts

@@ -1,15 +1,16 @@
 import { z } from "zod/v4";
-import { Examples } from "../examples.js";
-import { Limitations, steamTable } from "./steam.sql.js";
 import { fn } from "../utils/fn.js";
 import { Actor } from "../actor.js";
-import { Database } from "../drizzle/index.js";
+import { Examples } from "../examples.js";
+import { Identifier } from "../id/index.js";
 import { eq, isNull, and } from "drizzle-orm";
+import { Database } from "../drizzle/index.js";
+import { Limitations, steamTable } from "./steam.sql.js";
 
 export namespace Steam {
   export const Info = z
     .object({
-      id: z.string().meta({
+      id: Identifier.schema("steam").meta({
         description: "The unique Steam ID of the account",
         example: Examples.SteamAccount.id,
       }),

packages/core/src/user/index.ts

@@ -1,16 +1,16 @@
 import { z } from "zod/v4";
 import { fn } from "../utils/fn.js";
 import { userTable } from "./user.sql.js";
-import { createID } from "../utils/id.js";
 import { Examples } from "../examples.js";
 import { Polar } from "../polar/index.js";
+import { Identifier } from "../id/index.js";
 import { Database } from "../drizzle/index.js";
 import { eq, and, isNotNull } from "drizzle-orm";
 
 export namespace User {
   export const Info = z
     .object({
-      id: z.string().meta({
+      id: Identifier.schema("user").meta({
         description: "The unique identifier of the user",
         example: Examples.User.id,
       }),
@@ -38,7 +38,7 @@ export namespace User {
   export const create = fn(
     Info.omit({ customerID: true }).partial({ id: true }),
     async (input) => {
-      const id = input.id ?? createID("user");
+      const id = Identifier.ascending("user", input.id);
 
       const customerID = await Polar.fromUserEmail(input.email).then(
         (z) => z.id,

packages/core/src/utils/id.ts

@@ -1,25 +0,0 @@
-import { ulid } from "ulid";
-
-export const prefixes = {
-  user: "usr",
-  steam: "stm",
-  app: "app",
-  member: "mbr",
-  apiSecret: "sec",
-  apiPersonal: "pat",
-  organisation: "org",
-} as const;
-
-/**
- * Generates a unique identifier by concatenating a predefined prefix with a ULID.
- *
- * Given a key from the predefined prefixes mapping (e.g.,"user", "member", "steam"),
- * this function retrieves the corresponding prefix and combines it with a ULID using an underscore
- * as a separator. The resulting identifier is formatted as "prefix_ulid".
- *
- * @param prefix - A key from the prefixes mapping.
- * @returns A unique identifier string.
- */
-export function createID(prefix: keyof typeof prefixes): string {
-  return [prefixes[prefix], ulid()].join("_");
-}