From 7d2fd7b4f8d5ab7e27bfbea6a4498edbbaf7df9c Mon Sep 17 00:00:00 2001
From: Rory& <root@rory.gay>
Date: Fri, 3 Oct 2025 20:29:32 +0200
Subject: [PATCH] Add dotnet-ish Random class

---
 src/api/util/utility/String.ts |  4 +-
 src/util/entities/User.ts      |  4 +-
 src/util/util/Random.ts        | 74 ++++++++++++++++++++++++++++++++++
 src/util/util/index.ts         |  1 +
 4 files changed, 79 insertions(+), 4 deletions(-)
 create mode 100644 src/util/util/Random.ts

diff --git a/src/api/util/utility/String.ts b/src/api/util/utility/String.ts
index eef69e39..348f33cf 100644
--- a/src/api/util/utility/String.ts
+++ b/src/api/util/utility/String.ts
@@ -18,7 +18,7 @@
 
 import { Request } from "express";
 import { ntob } from "./Base64";
-import { FieldErrors } from "@spacebar/util";
+import { FieldErrors, Random } from "@spacebar/util";
 
 export function checkLength(
 	str: string,
@@ -40,5 +40,5 @@ export function checkLength(
 }
 
 export function generateCode() {
-	return ntob(Date.now() + Math.randomIntBetween(0, 10000));
+	return ntob(Date.now() + Random.nextInt(0, 10000));
 }
diff --git a/src/util/entities/User.ts b/src/util/entities/User.ts
index 2375008e..d1b3c709 100644
--- a/src/util/entities/User.ts
+++ b/src/util/entities/User.ts
@@ -19,7 +19,7 @@
 import { Request } from "express";
 import { Column, Entity, FindOneOptions, JoinColumn, OneToMany, OneToOne } from "typeorm";
 import { Channel, ChannelType, Config, Email, FieldErrors, Snowflake, trimSpecial } from "..";
-import { BitField } from "../util/BitField";
+import { BitField, Random } from "../util";
 import { BaseClass } from "./BaseClass";
 import { ConnectedAccount } from "./ConnectedAccount";
 import { Member } from "./Member";
@@ -284,7 +284,7 @@ export class User extends BaseClass {
 			// randomly generates a discriminator between 1 and 9999 and checks max five times if it already exists
 			// TODO: is there any better way to generate a random discriminator only once, without checking if it already exists in the database?
 			for (let tries = 0; tries < 5; tries++) {
-				const discriminator = Math.randomIntBetween(1, 9999).toString().padStart(4, "0");
+				const discriminator = Random.nextInt(1, 9999).toString().padStart(4, "0");
 				const exists = await User.findOne({
 					where: { discriminator, username: username },
 					select: ["id"],
diff --git a/src/util/util/Random.ts b/src/util/util/Random.ts
new file mode 100644
index 00000000..8e4598dc
--- /dev/null
+++ b/src/util/util/Random.ts
@@ -0,0 +1,74 @@
+// Inspired by dotnet: https://learn.microsoft.com/en-us/dotnet/api/system.random?view=net-9.0#methods
+export class Random {
+	public static nextInt(min?: number, max?: number): number {
+		if (min === undefined && max === undefined) {
+			// Next()
+			return Math.floor(Math.random() * Number.MAX_SAFE_INTEGER);
+		} else if (max === undefined) {
+			// Next(Int32)
+			if (min! <= 0) throw new RangeError("min must be greater than 0");
+			return Math.floor(Math.random() * min!);
+		} else {
+			// Next(Int32, Int32)
+			if (min! >= max!) throw new RangeError("min must be less than max");
+			return Math.floor(Math.random() * (max! - min!)) + min!;
+		}
+	}
+
+	public static nextDouble(min?: number, max?: number): number {
+		if (min === undefined && max === undefined) {
+			// NextDouble()
+			return Math.random();
+		} else if (max === undefined) {
+			// NextDouble(Double)
+			if (min! <= 0) throw new RangeError("min must be greater than 0");
+			return Math.random() * min!;
+		} else {
+			// NextDouble(Double, Double)
+			if (min! >= max!) throw new RangeError("min must be less than max");
+			return Math.random() * (max! - min!) + min!;
+		}
+	}
+
+	public static nextBytes(count: number): Uint8Array {
+		if (count <= 0) throw new RangeError("count must be greater than 0");
+		const arr = new Uint8Array(count);
+		for (let i = 0; i < count; i++) {
+			arr[i] = Math.floor(Math.random() * 256);
+		}
+		return arr;
+	}
+
+	public static nextBytesArray(count: number) {
+		if (count <= 0) throw new RangeError("count must be greater than 0");
+		const arr = [];
+		for (let i = 0; i < count; i++) {
+			arr.push(Math.floor(Math.random() * 256));
+		}
+		return arr;
+	}
+
+	public static getItems<T>(items: T[], count: number): T[] {
+		if (count <= 0) throw new RangeError("count must be greater than 0");
+		if (count >= items.length) return this.shuffle(items);
+		const usedIndices = new Set<number>();
+		const result: T[] = [];
+		while (result.length < count && usedIndices.size < items.length) {
+			const index = Math.floor(Math.random() * items.length);
+			if (!usedIndices.has(index)) {
+				usedIndices.add(index);
+				result.push(items[index]);
+			}
+		}
+		return result;
+	}
+
+	public static shuffle<T>(items: T[]): T[] {
+		const array = [...items];
+		for (let i = array.length - 1; i > 0; i--) {
+			const j = Math.floor(Math.random() * (i + 1));
+			[array[i], array[j]] = [array[j], array[i]];
+		}
+		return array;
+	}
+}
diff --git a/src/util/util/index.ts b/src/util/util/index.ts
index e7d8caa9..f50db274 100644
--- a/src/util/util/index.ts
+++ b/src/util/util/index.ts
@@ -48,3 +48,4 @@ export * from "./Application";
 export * from "./NameValidation";
 export * from "./HelperTypes";
 export * from "./extensions";
+export * from "./Random";
\ No newline at end of file