refactor: centralize provider projections

src/modules/investments/instruments/application/candle.service.ts

@@ -5,10 +5,8 @@ import {
 } from '@nestjs/common';
 import { randomUUID } from 'node:crypto';
 
-import { formatDecimal } from '../../../../common/decimal';
 import { StructuredLogger } from '../../../../common/logging/structured-logger.service';
 import { MILLISECONDS_PER_DAY } from '../../../../common/time';
-import { decimal } from '../../../../integrations/tbank/decimal';
 import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import {
   TbankAccessService,
@@ -26,6 +24,7 @@ import {
 } from '../domain/candle-coverage';
 import { InstrumentErrorCode } from '../domain/instrument-error-code';
 import { CandleRepository } from '../infrastructure/candle.repository';
+import { toSavedCandle } from '../infrastructure/tbank-candle.mapper';
 import { CatalogEnrichmentService } from './catalog-enrichment.service';
 import { timestamp } from './instrument-market';
 
@@ -413,17 +412,7 @@ export class CandleService {
         window.from,
         new Date(Math.min(window.to.valueOf(), now.valueOf())),
       );
-      const rows = candles.flatMap((candle) => {
-        const time = timestamp(candle.time);
-        if (!time || !candle.close) throw new Error('Invalid candle response');
-        return [
-          {
-            time,
-            close: formatDecimal(decimal(candle.close)),
-            isComplete: candle.isComplete === true,
-          },
-        ];
-      });
+      const rows = candles.map(toSavedCandle);
       if (!(await this.repository.stage(attempt, window, rows, now))) {
         return false;
       }

src/modules/investments/instruments/application/catalog-enrichment.service.ts

@@ -4,7 +4,6 @@ import { randomUUID } from 'node:crypto';
 import {
   decimalFromString,
   divide,
-  formatDecimal,
 } from '../../../../common/decimal';
 import { StructuredLogger } from '../../../../common/logging/structured-logger.service';
 import {
@@ -13,7 +12,6 @@ import {
 } from '../../../../common/time';
 import { type MoexBondEvent, MoexClient } from '../../../../integrations/moex/moex.api';
 import { NcrRatingsClient } from '../../../../integrations/ncr/ncr.api';
-import { decimal } from '../../../../integrations/tbank/decimal';
 import { isTbankErrorCode, TbankErrorCode } from '../../../../integrations/tbank/tbank-error-code';
 import {
   TbankAccessService,
@@ -37,6 +35,7 @@ import {
   catalogScope,
   type CatalogSource,
 } from '../infrastructure/catalog-discovery.repository';
+import { toSavedCandle } from '../infrastructure/tbank-candle.mapper';
 import { catalogSearchLimit } from './catalog-selection';
 import { previousClose, timestamp } from './instrument-market';
 
@@ -353,17 +352,7 @@ export class CatalogEnrichmentService {
           gap.from,
           gap.to,
         );
-        const rows = response.map((candle) => {
-          const time = timestamp(candle.time);
-          if (!time || !candle.close) {
-            throw new Error('Invalid candle response');
-          }
-          return {
-            time,
-            close: formatDecimal(decimal(candle.close)),
-            isComplete: candle.isComplete === true,
-          };
-        });
+        const rows = response.map(toSavedCandle);
         if (!(await this.candles.stage(attempt, gap, rows, now))) {
           throw new Error('Cancelled candle comparison');
         }

src/modules/investments/instruments/infrastructure/tbank-candle.mapper.spec.ts

@@ -0,0 +1,19 @@
+import { toSavedCandle } from './tbank-candle.mapper';
+
+describe('T-Bank candle mapping', () => {
+  it('keeps signed nano precision and requires explicit completeness', () => {
+    const input = { time: { seconds: '1767225600' }, close: { units: '0', nano: -1 } };
+    expect(toSavedCandle(input)).toEqual({
+      time: '2026-01-01T00:00:00.000Z', close: '-0.000000001', isComplete: false,
+    });
+    expect(toSavedCandle({ ...input, isComplete: true }).isComplete).toBe(true);
+    expect(input).toEqual({ time: { seconds: '1767225600' }, close: { units: '0', nano: -1 } });
+  });
+  it.each([
+    { close: { units: '1' } },
+    { time: { seconds: 'invalid' }, close: { units: '1' } },
+    { time: { seconds: '1767225600' } },
+  ])('rejects missing or malformed source fields: %j', (input) => {
+    expect(() => toSavedCandle(input)).toThrow('Invalid candle response');
+  });
+});

src/modules/investments/instruments/infrastructure/tbank-candle.mapper.ts

@@ -0,0 +1,18 @@
+import type { TbankCandle } from '../../../../integrations/tbank/tbank.api';
+import type { SavedCandle } from '../domain/candle-coverage';
+
+import { formatDecimal } from '../../../../common/decimal';
+import { decimal } from '../../../../integrations/tbank/decimal';
+import { timestamp } from '../application/instrument-market';
+
+function toSavedCandle(candle: TbankCandle): SavedCandle {
+  const time = timestamp(candle.time);
+  if (!time || !candle.close) throw new Error('Invalid candle response');
+  return {
+    time,
+    close: formatDecimal(decimal(candle.close)),
+    isComplete: candle.isComplete === true,
+  };
+}
+
+export { toSavedCandle };