chore: use 64-bit RNG everywhere (#2030)

Closes #2026

Reviewed-on: #2030
Co-authored-by: Sainan <63328889+Sainan@users.noreply.github.com>
Co-committed-by: Sainan <63328889+Sainan@users.noreply.github.com>

src/controllers/api/modularWeaponSaleController.ts

@@ -2,7 +2,7 @@ import { RequestHandler } from "express";
 import { ExportWeapons } from "warframe-public-export-plus";
 import { IMongoDate } from "@/src/types/commonTypes";
 import { toMongoDate } from "@/src/helpers/inventoryHelpers";
-import { CRng } from "@/src/services/rngService";
+import { SRng } from "@/src/services/rngService";
 import { ArtifactPolarity, EquipmentFeatures } from "@/src/types/inventoryTypes/commonInventoryTypes";
 import { getJSONfromString } from "@/src/helpers/stringHelpers";
 import {
@@ -140,7 +140,7 @@ const getModularWeaponSale = (
     partTypes: string[],
     getItemType: (parts: string[]) => string
 ): IModularWeaponSaleInfo => {
-    const rng = new CRng(day);
+    const rng = new SRng(day);
     const parts = partTypes.map(partType => rng.randomElement(partTypeToParts[partType])!);
     let partsCost = 0;
     for (const part of parts) {

src/services/loginRewardService.ts

@@ -1,7 +1,7 @@
 import randomRewards from "@/static/fixed_responses/loginRewards/randomRewards.json";
 import { IInventoryChanges } from "../types/purchaseTypes";
 import { TAccountDocument } from "./loginService";
-import { CRng, mixSeeds } from "./rngService";
+import { mixSeeds, SRng } from "./rngService";
 import { TInventoryDatabaseDocument } from "../models/inventoryModels/inventoryModel";
 import { addBooster, updateCurrency } from "./inventoryService";
 import { handleStoreItemAcquisition } from "./purchaseService";
@@ -49,8 +49,8 @@ const scaleAmount = (day: number, amount: number, scalingMultiplier: number): nu
 // Always produces the same result for the same account _id & LoginDays pair.
 export const isLoginRewardAChoice = (account: TAccountDocument): boolean => {
     const accountSeed = parseInt(account._id.toString().substring(16), 16);
-    const rng = new CRng(mixSeeds(accountSeed, account.LoginDays));
+    const rng = new SRng(mixSeeds(accountSeed, account.LoginDays));
-    return rng.random() < 0.25; // Using 25% as an approximate chance for pick-a-doors. More conclusive data analysis is needed.
+    return rng.randomFloat() < 0.25;
 };
 
 // Always produces the same result for the same account _id & LoginDays pair.
@@ -59,8 +59,8 @@ export const getRandomLoginRewards = (
     inventory: TInventoryDatabaseDocument
 ): ILoginReward[] => {
     const accountSeed = parseInt(account._id.toString().substring(16), 16);
-    const rng = new CRng(mixSeeds(accountSeed, account.LoginDays));
+    const rng = new SRng(mixSeeds(accountSeed, account.LoginDays));
-    const pick_a_door = rng.random() < 0.25; // Using 25% as an approximate chance for pick-a-doors. More conclusive data analysis is needed.
+    const pick_a_door = rng.randomFloat() < 0.25;
     const rewards = [getRandomLoginReward(rng, account.LoginDays, inventory)];
     if (pick_a_door) {
         do {
@@ -73,7 +73,7 @@ export const getRandomLoginRewards = (
     return rewards;
 };
 
-const getRandomLoginReward = (rng: CRng, day: number, inventory: TInventoryDatabaseDocument): ILoginReward => {
+const getRandomLoginReward = (rng: SRng, day: number, inventory: TInventoryDatabaseDocument): ILoginReward => {
     const reward = rng.randomReward(randomRewards)!;
     //const reward = randomRewards.find(x => x.RewardType == "RT_BOOSTER")!;
     if (reward.RewardType == "RT_RANDOM_RECIPE") {

src/services/rngService.ts

@@ -86,54 +86,12 @@ export const mixSeeds = (seed1: number, seed2: number): number => {
     return seed >>> 0;
 };
 
-// Seeded RNG for internal usage. Based on recommendations in the ISO C standards.
+// Seeded RNG with identical results to the game client. Based on work by Donald Knuth.
-export class CRng {
-    state: number;
-
-    constructor(seed: number = 1) {
-        this.state = seed;
-    }
-
-    random(): number {
-        this.state = (this.state * 1103515245 + 12345) & 0x7fffffff;
-        return (this.state & 0x3fffffff) / 0x3fffffff;
-    }
-
-    randomInt(min: number, max: number): number {
-        const diff = max - min;
-        if (diff != 0) {
-            if (diff < 0) {
-                throw new Error(`max must be greater than min`);
-            }
-            if (diff > 0x3fffffff) {
-                throw new Error(`insufficient entropy`);
-            }
-            min += Math.floor(this.random() * (diff + 1));
-        }
-        return min;
-    }
-
-    randomElement<T>(arr: readonly T[]): T | undefined {
-        return arr[Math.floor(this.random() * arr.length)];
-    }
-
-    randomReward<T extends { probability: number }>(pool: T[]): T | undefined {
-        return getRewardAtPercentage(pool, this.random());
-    }
-
-    churnSeed(its: number): void {
-        while (its--) {
-            this.state = (this.state * 1103515245 + 12345) & 0x7fffffff;
-        }
-    }
-}
-
-// Seeded RNG for cases where we need identical results to the game client. Based on work by Donald Knuth.
 export class SRng {
     state: bigint;
 
-    constructor(seed: bigint) {
+    constructor(seed: bigint | number) {
-        this.state = seed;
+        this.state = BigInt(seed);
     }
 
     randomInt(min: number, max: number): number {

src/services/serversideVendorsService.ts

@@ -1,6 +1,6 @@
 import { unixTimesInMs } from "@/src/constants/timeConstants";
 import { catBreadHash } from "@/src/helpers/stringHelpers";
-import { CRng, mixSeeds } from "@/src/services/rngService";
+import { mixSeeds, SRng } from "@/src/services/rngService";
 import { IMongoDate } from "@/src/types/commonTypes";
 import { IItemManifest, IVendorInfo, IVendorManifest } from "@/src/types/vendorTypes";
 import { ExportVendors, IRange } from "warframe-public-export-plus";
@@ -204,7 +204,7 @@ const generateVendorManifest = (vendorInfo: IGeneratableVendorInfo): IVendorMani
         const cycleOffset = vendorInfo.cycleOffset ?? 1734307200_000;
         const cycleDuration = vendorInfo.cycleDuration;
         const cycleIndex = Math.trunc((Date.now() - cycleOffset) / cycleDuration);
-        const rng = new CRng(mixSeeds(vendorSeed, cycleIndex));
+        const rng = new SRng(mixSeeds(vendorSeed, cycleIndex));
         const manifest = ExportVendors[vendorInfo.TypeName];
         const offersToAdd = [];
         if (manifest.numItems && !manifest.isOneBinPerCycle) {
@@ -247,8 +247,7 @@ const generateVendorManifest = (vendorInfo: IGeneratableVendorInfo): IVendorMani
                     $oid:
                         ((cycleStart / 1000) & 0xffffffff).toString(16).padStart(8, "0") +
                         vendorInfo._id.$oid.substring(8, 16) +
-                        rng.randomInt(0, 0xffff).toString(16).padStart(4, "0") +
+                        rng.randomInt(0, 0xffff_ffff).toString(16).padStart(8, "0")
-                        rng.randomInt(0, 0xffff).toString(16).padStart(4, "0")
                 }
             };
             if (rawItem.numRandomItemPrices) {
@@ -283,9 +282,9 @@ const generateVendorManifest = (vendorInfo: IGeneratableVendorInfo): IVendorMani
                 item.PremiumPrice = [value, value];
             }
             if (vendorInfo.RandomSeedType) {
-                item.LocTagRandSeed = (rng.randomInt(0, 0xffff) << 16) | rng.randomInt(0, 0xffff);
+                item.LocTagRandSeed = rng.randomInt(0, 0xffff_ffff);
                 if (vendorInfo.RandomSeedType == "VRST_WEAPON") {
-                    const highDword = (rng.randomInt(0, 0xffff) << 16) | rng.randomInt(0, 0xffff);
+                    const highDword = rng.randomInt(0, 0xffff_ffff);
                     item.LocTagRandSeed = (BigInt(highDword) << 32n) | (BigInt(item.LocTagRandSeed) & 0xffffffffn);
                 }
             }

src/services/worldStateService.ts

@@ -5,7 +5,7 @@ import syndicateMissions from "@/static/fixed_responses/worldState/syndicateMiss
 import { buildConfig } from "@/src/services/buildConfigService";
 import { unixTimesInMs } from "@/src/constants/timeConstants";
 import { config } from "@/src/services/configService";
-import { CRng, SRng } from "@/src/services/rngService";
+import { SRng } from "@/src/services/rngService";
 import { ExportNightwave, ExportRegions, IRegion } from "warframe-public-export-plus";
 import {
     ICalendarDay,
@@ -193,7 +193,7 @@ const pushSyndicateMissions = (
 ): void => {
     const nodeOptions: string[] = [...syndicateMissions];
 
-    const rng = new CRng(seed);
+    const rng = new SRng(seed);
     const nodes: string[] = [];
     for (let i = 0; i != 6; ++i) {
         const index = rng.randomInt(0, nodeOptions.length - 1);
@@ -235,8 +235,8 @@ const pushTilesetModifiers = (modifiers: string[], tileset: TSortieTileset): voi
 };
 
 export const getSortie = (day: number): ISortie => {
-    const seed = new CRng(day).randomInt(0, 100_000);
+    const seed = new SRng(day).randomInt(0, 100_000);
-    const rng = new CRng(seed);
+    const rng = new SRng(seed);
 
     const boss = rng.randomElement(sortieBosses)!;
 
@@ -351,7 +351,7 @@ const dailyChallenges = Object.keys(ExportNightwave.challenges).filter(x =>
 const getSeasonDailyChallenge = (day: number): ISeasonChallenge => {
     const dayStart = EPOCH + day * 86400000;
     const dayEnd = EPOCH + (day + 3) * 86400000;
-    const rng = new CRng(new CRng(day).randomInt(0, 100_000));
+    const rng = new SRng(new SRng(day).randomInt(0, 100_000));
     return {
         _id: { $oid: "67e1b5ca9d00cb47" + day.toString().padStart(8, "0") },
         Daily: true,
@@ -371,7 +371,7 @@ const getSeasonWeeklyChallenge = (week: number, id: number): ISeasonChallenge =>
     const weekStart = EPOCH + week * 604800000;
     const weekEnd = weekStart + 604800000;
     const challengeId = week * 7 + id;
-    const rng = new CRng(new CRng(challengeId).randomInt(0, 100_000));
+    const rng = new SRng(new SRng(challengeId).randomInt(0, 100_000));
     return {
         _id: { $oid: "67e1bb2d9d00cb47" + challengeId.toString().padStart(8, "0") },
         Activation: { $date: { $numberLong: weekStart.toString() } },
@@ -388,7 +388,7 @@ const getSeasonWeeklyHardChallenge = (week: number, id: number): ISeasonChalleng
     const weekStart = EPOCH + week * 604800000;
     const weekEnd = weekStart + 604800000;
     const challengeId = week * 7 + id;
-    const rng = new CRng(new CRng(challengeId).randomInt(0, 100_000));
+    const rng = new SRng(new SRng(challengeId).randomInt(0, 100_000));
     return {
         _id: { $oid: "67e1bb2d9d00cb47" + challengeId.toString().padStart(8, "0") },
         Activation: { $date: { $numberLong: weekStart.toString() } },
@@ -432,12 +432,12 @@ export const pushClassicBounties = (syndicateMissions: ISyndicateMissionInfo[],
 
     // TODO: xpAmounts need to be calculated based on the jobType somehow?
 
-    const seed = new CRng(bountyCycle).randomInt(0, 100_000);
+    const seed = new SRng(bountyCycle).randomInt(0, 100_000);
     const bountyCycleStart = bountyCycle * 9000000;
     const bountyCycleEnd = bountyCycleStart + 9000000;
 
     {
-        const rng = new CRng(seed);
+        const rng = new SRng(seed);
         syndicateMissions.push({
             _id: {
                 $oid: ((bountyCycleStart / 1000) & 0xffffffff).toString(16).padStart(8, "0") + "0000000000000008"
@@ -509,7 +509,7 @@ export const pushClassicBounties = (syndicateMissions: ISyndicateMissionInfo[],
     }
 
     {
-        const rng = new CRng(seed);
+        const rng = new SRng(seed);
         syndicateMissions.push({
             _id: {
                 $oid: ((bountyCycleStart / 1000) & 0xffffffff).toString(16).padStart(8, "0") + "0000000000000025"
@@ -581,7 +581,7 @@ export const pushClassicBounties = (syndicateMissions: ISyndicateMissionInfo[],
     }
 
     {
-        const rng = new CRng(seed);
+        const rng = new SRng(seed);
         syndicateMissions.push({
             _id: {
                 $oid: ((bountyCycleStart / 1000) & 0xffffffff).toString(16).padStart(8, "0") + "0000000000000002"
@@ -701,7 +701,7 @@ const getCalendarSeason = (week: number): ICalendarSeason => {
         //logger.debug(`birthday on day ${day}`);
         eventDays.push({ day, events: [] }); // This is how CET_PLOT looks in worldState as of around 38.5.0
     }
-    const rng = new CRng(new CRng(week).randomInt(0, 100_000));
+    const rng = new SRng(new SRng(week).randomInt(0, 100_000));
     const challenges = [
         "/Lotus/Types/Challenges/Calendar1999/CalendarKillEnemiesEasy",
         "/Lotus/Types/Challenges/Calendar1999/CalendarKillEnemiesMedium",
@@ -982,7 +982,7 @@ export const getWorldState = (buildLabel?: string): IWorldState => {
     }
 
     // Elite Sanctuary Onslaught cycling every week
-    worldState.NodeOverrides.find(x => x.Node == "SolNode802")!.Seed = new SRng(BigInt(week)).randomInt(0, 0xff_ffff);
+    worldState.NodeOverrides.find(x => x.Node == "SolNode802")!.Seed = new SRng(week).randomInt(0, 0xff_ffff);
 
     // Holdfast, Cavia, & Hex bounties cycling every 2.5 hours; unfaithful implementation
     let bountyCycle = Math.trunc(Date.now() / 9000000);
@@ -1068,7 +1068,7 @@ export const getWorldState = (buildLabel?: string): IWorldState => {
 
         // The client does not seem to respect activation for classic syndicate missions, so only pushing current ones.
         const sdy = Date.now() >= rollover ? day : day - 1;
-        const rng = new CRng(sdy);
+        const rng = new SRng(sdy);
         pushSyndicateMissions(worldState, sdy, rng.randomInt(0, 100_000), "ba6f84724fa48049", "ArbitersSyndicate");
         pushSyndicateMissions(worldState, sdy, rng.randomInt(0, 100_000), "ba6f84724fa4804a", "CephalonSudaSyndicate");
         pushSyndicateMissions(worldState, sdy, rng.randomInt(0, 100_000), "ba6f84724fa4804e", "NewLokaSyndicate");
@@ -1184,8 +1184,8 @@ export const getLiteSortie = (week: number): ILiteSortie => {
         }
     }
 
-    const seed = new CRng(week).randomInt(0, 100_000);
+    const seed = new SRng(week).randomInt(0, 100_000);
-    const rng = new CRng(seed);
+    const rng = new SRng(seed);
     const firstNodeIndex = rng.randomInt(0, nodes.length - 1);
     const firstNode = nodes[firstNodeIndex];
     nodes.splice(firstNodeIndex, 1);