refactor xmr rate module to exchange rate module for multi crypto support

backend/src/modules/exchangeRate/dto/CoingeckoSimplePriceResponseDto.ts

@@ -0,0 +1,55 @@
+import {
+    IsArray,
+    IsEnum,
+    IsNotEmpty,
+    IsObject,
+    IsString,
+    Validate,
+    ValidatorConstraint,
+    type ValidationArguments,
+    type ValidatorConstraintInterface
+} from 'class-validator';
+import { ShopFiatCurrency } from '../../../types/ShopFiatCurrency';
+
+@ValidatorConstraint({ name: 'coingeckoResponse' })
+class CoingeckoResponseConstraint implements ValidatorConstraintInterface {
+    validate(response: Record<string, unknown>, args: ValidationArguments): boolean {
+        const { shopFiatCurrency, coinIds } = args.object as CoingeckoSimplePriceResponseDto;
+
+        if (!shopFiatCurrency || coinIds.length === 0) {
+            return false;
+        }
+
+        const fiatKey = shopFiatCurrency.toLowerCase();
+
+        return coinIds.every(coinId => {
+            const coin = response[coinId];
+
+            if (typeof coin !== 'object' || coin === null) {
+                return false;
+            }
+
+            const rate = coin[fiatKey];
+
+            return typeof rate === 'number' && Number.isFinite(rate) && rate > 0;
+        });
+    }
+
+    defaultMessage(): string {
+        return 'CoinGecko coin fiat rate must be a positive number';
+    }
+}
+
+export class CoingeckoSimplePriceResponseDto {
+    @IsEnum(ShopFiatCurrency)
+    shopFiatCurrency: ShopFiatCurrency;
+
+    @IsArray()
+    @IsString({ each: true })
+    coinIds: string[];
+
+    @IsNotEmpty()
+    @IsObject()
+    @Validate(CoingeckoResponseConstraint)
+    response: Record<string, Record<string, number>>;
+}