feat(#40): Show an appraised estimate of held items on the ledger

src/ledger/balanceAppraisal.spec.ts

@@ -0,0 +1,34 @@
+import {describe, expect, test} from 'vitest';
+import {appraiseItemBalances} from './balanceAppraisal';
+import type {MarketTypePrice} from '@/market';
+
+const price = (id: number, buy: number, sell: number): MarketTypePrice => ({
+    type: {id, name: `type-${id}`} as MarketTypePrice['type'],
+    buy,
+    sell,
+    orderCount: 1,
+});
+
+describe('appraiseItemBalances', () => {
+    test('sums quantity times buy and sell across stacks', () => {
+        const result = appraiseItemBalances(
+            [{typeId: 1, quantity: 2}, {typeId: 2, quantity: 3}],
+            [price(1, 10, 12), price(2, 100, 110)],
+        );
+
+        expect(result).toEqual({buy: 2 * 10 + 3 * 100, sell: 2 * 12 + 3 * 110});
+    });
+
+    test('ignores stacks with no resolved price', () => {
+        const result = appraiseItemBalances(
+            [{typeId: 1, quantity: 2}, {typeId: 99, quantity: 5}],
+            [price(1, 10, 12)],
+        );
+
+        expect(result).toEqual({buy: 20, sell: 24});
+    });
+
+    test('returns zero totals for no items', () => {
+        expect(appraiseItemBalances([], [])).toEqual({buy: 0, sell: 0});
+    });
+});

src/ledger/balanceAppraisal.ts

@@ -0,0 +1,25 @@
+import {ItemBalanceResponse} from "@/generated/mammon";
+import {MarketTypePrice} from "@/market";
+
+export interface ItemBalanceAppraisal {
+    buy: number;
+    sell: number;
+}
+
+export const appraiseItemBalances = (
+    itemBalances: ItemBalanceResponse[],
+    prices: MarketTypePrice[],
+): ItemBalanceAppraisal => {
+    const priceByTypeId = new Map(prices.map(p => [p.type.id, p]));
+
+    return itemBalances.reduce<ItemBalanceAppraisal>((totals, {typeId, quantity}) => {
+        const price = priceByTypeId.get(typeId);
+
+        if (price) {
+            totals.buy += quantity * price.buy;
+            totals.sell += quantity * price.sell;
+        }
+
+        return totals;
+    }, {buy: 0, sell: 0});
+};

src/ledger/index.ts

@@ -1,4 +1,5 @@
 export * from './ledger';
+export * from './balanceAppraisal';
 
 export {default as LedgerLabel} from './LedgerLabel.vue';
 export {default as LedgerSelect} from './LedgerSelect.vue';