perf: batch bank operation page relations (WealthLedger/backend#68)

Closes #68

src/modules/banking/bank-cards/application/bank-operations.service.ts

@@ -91,6 +91,101 @@ export class BankOperationsService {
     };
   }
 
+  private async pageViews(tx: Tx, rows: BankCardOperation[]) {
+    const userId = rows[0]?.userId;
+    if (!userId) return [];
+    const cardIds = new Set(
+      rows.flatMap((row) =>
+        [row.cardId, row.targetCardId].filter(
+          (id): id is string => id !== null,
+        ),
+      ),
+    );
+    const sourceIds = new Set(
+      rows.flatMap((row) => (row.originalExpenseId ? [row.originalExpenseId] : [])),
+    );
+    const [cards, sources] = await Promise.all([
+      tx.bankCard.findMany({ where: { userId, id: { in: [...cardIds] } } }),
+      tx.bankCardOperation.findMany({
+        where: { userId, id: { in: [...sourceIds] } },
+      }),
+    ]);
+    const categoryIds = new Set(
+      rows
+        .map(
+          (row) =>
+            sources.find((source) => source.id === row.originalExpenseId)
+              ?.categoryId ?? row.categoryId,
+        )
+        .filter((id): id is string => id !== null),
+    );
+    const expenseIds = new Set(
+      rows.flatMap((row) => {
+        const source = sources.find((item) => item.id === row.originalExpenseId);
+        return row.kind === BankOperationKind.Expense || source
+          ? [source?.id ?? row.id]
+          : [];
+      }),
+    );
+    const [categories, refunds] = await Promise.all([
+      tx.expenseCategory.findMany({
+        where: { userId, id: { in: [...categoryIds] } },
+      }),
+      tx.bankCardOperation.findMany({
+        where: {
+          userId,
+          originalExpenseId: { in: [...expenseIds] },
+          deletedAt: null,
+        },
+      }),
+    ]);
+    const cardsById = new Map(cards.map((card) => [card.id, card]));
+    const sourcesById = new Map(sources.map((source) => [source.id, source]));
+    const categoriesById = new Map(categories.map((category) => [category.id, category]));
+    return rows.map((row) => {
+      const card = cardsById.get(row.cardId) as { name: string };
+      const target = row.targetCardId ? cardsById.get(row.targetCardId) : null;
+      const source = row.originalExpenseId
+        ? sourcesById.get(row.originalExpenseId)
+        : null;
+      const categoryId = source?.categoryId ?? row.categoryId;
+      const relatedRefunds =
+        row.kind === BankOperationKind.Expense || source
+          ? refunds.filter(
+              (refund) =>
+                refund.originalExpenseId === (source?.id ?? row.id) &&
+                (!source || refund.id !== row.id),
+            )
+          : [];
+      return {
+        id: row.id,
+        kind: row.kind as BankOperationDto['kind'],
+        cardId: row.cardId,
+        cardName: card.name,
+        targetCardId: row.targetCardId,
+        targetCardName: target?.name ?? null,
+        categoryId,
+        categoryName: categoriesById.get(categoryId ?? '')?.name ?? null,
+        originalExpenseId: row.originalExpenseId,
+        amount: rubMoney(row.amountKopecks),
+        availableRefund:
+          row.kind === BankOperationKind.Expense || source
+            ? rubMoney(
+                (source?.amountKopecks ?? row.amountKopecks) -
+                relatedRefunds.reduce(
+                  (sum, refund) => sum + refund.amountKopecks,
+                  ZERO_KOPECKS,
+                ),
+              )
+            : null,
+        date: row.date,
+        description: row.description,
+        version: row.version,
+        createdAt: row.createdAt.toISOString(),
+      };
+    });
+  }
+
   private async validateOperation(
     tx: Tx,
     userId: string,
@@ -359,9 +454,7 @@ export class BankOperationsService {
         take: limit,
       });
       return {
-        items: await Promise.all(
+        items: await this.pageViews(tx, rows),
-          rows.map((row) => this.operationView(tx, row)),
-        ),
         total,
         page,
         hasNext: page * limit < total,