feat: add legacy-compatible neutral auctions

packages/logic/src/auction/neutral.ts

@@ -0,0 +1,105 @@
+import { LiteHashDRBG, RandUtil } from '@sammo-ts/common';
+
+import { simpleSerialize } from '../war/utils.js';
+
+export type NeutralResourceAuctionType = 'BUY_RICE' | 'SELL_RICE';
+
+export interface NeutralAuctionPlanInput {
+    hiddenSeed: string | number;
+    seedYear: number;
+    seedMonth: number;
+    nationCount: number;
+    consumeTournamentRoll: boolean;
+    averageGold: number;
+    averageRice: number;
+    buyRiceAuctionCount: number;
+    sellRiceAuctionCount: number;
+}
+
+export interface NeutralResourceAuctionPlan {
+    auctionType: NeutralResourceAuctionType;
+    amount: number;
+    startBidAmount: number;
+    finishBidAmount: number;
+    closeTurnCnt: number;
+}
+
+const clamp = (value: number, min: number, max: number): number => {
+    if (max < min) {
+        return min;
+    }
+    return Math.min(max, Math.max(min, value));
+};
+
+const roundToTens = (value: number): number => Math.round(value / 10) * 10;
+
+const normalizeCount = (value: number): number => (Number.isFinite(value) ? Math.max(0, Math.floor(value)) : 0);
+
+const normalizeAverage = (value: number): number => clamp(Number.isFinite(value) ? value : 0, 1_000, 20_000);
+
+const canOpenResourceAuction = (plan: NeutralResourceAuctionPlan): boolean =>
+    plan.closeTurnCnt >= 1 &&
+    plan.closeTurnCnt <= 24 &&
+    plan.amount >= 100 &&
+    plan.amount <= 10_000 &&
+    plan.startBidAmount >= plan.amount * 0.5 &&
+    plan.startBidAmount <= plan.amount * 2 &&
+    plan.finishBidAmount >= plan.amount * 1.1 &&
+    plan.finishBidAmount <= plan.amount * 2 &&
+    plan.finishBidAmount >= plan.startBidAmount * 1.1;
+
+export const buildNeutralResourceAuctionPlan = (input: NeutralAuctionPlanInput): NeutralResourceAuctionPlan[] => {
+    // ref TurnExecutionHelper는 날짜를 넘기기 전에 이전 연월로 monthly RNG를 만든다.
+    const rng = new RandUtil(
+        new LiteHashDRBG(simpleSerialize(input.hiddenSeed, 'monthly', input.seedYear, input.seedMonth))
+    );
+
+    // ref postUpdateMonthly()의 국가 국력 보정이 registerAuction()보다 먼저 RNG를 소비한다.
+    for (let nationIdx = 0; nationIdx < normalizeCount(input.nationCount); nationIdx += 1) {
+        rng.nextRange(0.95, 1.05);
+    }
+    // 토너먼트가 없고 자동 개시가 켜진 경우 성공 여부와 무관하게 한 번 소비한다.
+    if (input.consumeTournamentRoll) {
+        rng.nextBool(0.4);
+    }
+
+    const averageGold = normalizeAverage(input.averageGold);
+    const averageRice = normalizeAverage(input.averageRice);
+    const result: NeutralResourceAuctionPlan[] = [];
+
+    const buyRiceAuctionCount = normalizeCount(input.buyRiceAuctionCount);
+    if (rng.nextBool(1 / (buyRiceAuctionCount + 5))) {
+        const multiplier = rng.nextRangeInt(1, 5);
+        const rawAmount = (averageRice / 20) * multiplier;
+        const rawStartBid = clamp((averageGold / 20) * 0.9 * multiplier, rawAmount * 0.8, rawAmount * 1.2);
+        const plan: NeutralResourceAuctionPlan = {
+            auctionType: 'BUY_RICE',
+            amount: roundToTens(rawAmount),
+            startBidAmount: roundToTens(rawStartBid),
+            finishBidAmount: roundToTens(rawAmount * 2),
+            closeTurnCnt: rng.nextRangeInt(3, 12),
+        };
+        if (canOpenResourceAuction(plan)) {
+            result.push(plan);
+        }
+    }
+
+    const sellRiceAuctionCount = normalizeCount(input.sellRiceAuctionCount);
+    if (rng.nextBool(1 / (sellRiceAuctionCount + 5))) {
+        const multiplier = rng.nextRangeInt(1, 5);
+        const rawAmount = (averageGold / 20) * multiplier;
+        const rawStartBid = clamp((averageRice / 20) * 1.1 * multiplier, rawAmount * 0.8, rawAmount * 1.2);
+        const plan: NeutralResourceAuctionPlan = {
+            auctionType: 'SELL_RICE',
+            amount: roundToTens(rawAmount),
+            startBidAmount: roundToTens(rawStartBid),
+            finishBidAmount: roundToTens(rawAmount * 2),
+            closeTurnCnt: rng.nextRangeInt(3, 12),
+        };
+        if (canOpenResourceAuction(plan)) {
+            result.push(plan);
+        }
+    }
+
+    return result;
+};

packages/logic/src/index.ts

@@ -2,6 +2,7 @@ export * from './domain/entities.js';
 export type { RandomGenerator } from '@sammo-ts/common';
 export * from './actions/index.js';
 export * from './auction/alias.js';
+export * from './auction/neutral.js';
 export * from './constraints/index.js';
 export * from './crewType/index.js';
 export * from './diplomacy/index.js';