feat(#17): Add an appraisal compare-by-location page

src/market/appraisal/compare.ts

@@ -0,0 +1,66 @@
+import {marketApi} from '@/mammon';
+import {getMarketTypes, MarketType} from '../type';
+import {MarketTypePrice} from './MarketTypePrice';
+
+export type LocationPrice = {
+    buyUnit: number;
+    sellUnit: number;
+    buy: number;
+    sell: number;
+};
+
+export type ComparedItem = {
+    typeId: number;
+    name: string;
+    quantity: number;
+    volume: number;
+    prices: Record<number, LocationPrice>;
+};
+
+export type PricesForLocation = (types: MarketType[], locationId: number) => Promise<MarketTypePrice[]>;
+
+export const compareAppraisal = async (
+    raw: string,
+    locationIds: number[],
+    getPrices: PricesForLocation
+): Promise<ComparedItem[]> => {
+    if (!raw?.trim() || locationIds.length === 0) {
+        return [];
+    }
+
+    const stacks = await marketApi.parseStacks(raw).then(r => r.data);
+
+    if (stacks.length === 0) {
+        return [];
+    }
+
+    const quantities = new Map(stacks.map(s => [s.marketTypeId, s.quantity]));
+    const types = await getMarketTypes(stacks.map(s => s.marketTypeId));
+
+    const rows = new Map<number, ComparedItem>(types.map(t => [t.id, {
+        typeId: t.id,
+        name: t.name,
+        quantity: quantities.get(t.id) ?? 0,
+        volume: t.volume,
+        prices: {},
+    }]));
+
+    const pricesByLocation = await Promise.all(
+        locationIds.map(async locationId => [locationId, await getPrices(types, locationId)] as const)
+    );
+
+    pricesByLocation.forEach(([locationId, prices]) => prices.forEach(p => {
+        const row = rows.get(p.type.id);
+
+        if (row) {
+            row.prices[locationId] = {
+                buyUnit: p.buy,
+                sellUnit: p.sell,
+                buy: p.buy * row.quantity,
+                sell: p.sell * row.quantity,
+            };
+        }
+    }));
+
+    return [...rows.values()];
+};