feat(currency-hub): add paginated search endpoint for fiat and crypto currency data

backend/src/currency-hub/currency-hub.controller.ts

@@ -1,3 +1,4 @@
+import { SearchCurrencyDto } from './dto/search-currency.dto'; 
 import {
   Controller,
   Get,
@@ -19,6 +20,11 @@ import { QueryCurrencyHubDto } from './dto/query-currency-hub.dto';
 export class CurrencyHubController {
   constructor(private readonly currencyHubService: CurrencyHubService) {}
 
+  @Get('search')
+searchWithPagination(@Query() dto: SearchCurrencyDto) {
+  return this.currencyHubService.searchAndPaginateCurrencies(dto);
+}
+
   @Post()
   create(@Body() createCurrencyHubDto: CreateCurrencyHubDto) {
     return this.currencyHubService.create(createCurrencyHubDto);

backend/src/currency-hub/currency-hub.service.spec.ts

@@ -407,4 +407,13 @@ describe('CurrencyHubService', () => {
       ).rejects.toThrow(NotFoundException);
     });
   });
+
+  describe('searchAndPaginateCurrencies', () => {
+  it('returns filtered and paginated results', async () => {
+    const result = await service.searchAndPaginateCurrencies({ search: 'usd', page: 1, limit: 5 });
+    expect(result).toHaveProperty('data');
+    expect(result).toHaveProperty('total');
+    expect(Array.isArray(result.data)).toBe(true);
+  });
+});
 });

backend/src/currency-hub/currency-hub.service.ts

@@ -1,4 +1,5 @@
 // src/currency-hub/currency-hub.service.ts
+import { SearchCurrencyDto } from './dto/search-currency.dto';
 import { Injectable, NotFoundException } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository, Between, FindOptionsWhere } from 'typeorm';
@@ -238,4 +239,32 @@ export class CurrencyHubService {
     // For demonstration purposes, we'll just log a message
     console.log('Updating exchange rates from external sources...');
   }
+
+  // Added Filter + Pagination
+  async searchAndPaginateCurrencies(
+  dto: SearchCurrencyDto,
+): Promise<{
+  data: CurrencyHub[];
+  total: number;
+  page: number;
+  limit: number;
+}> {
+  const { search, page = 1, limit = 10 } = dto;
+
+  const qb = this.currencyHubRepository.createQueryBuilder('currency');
+
+  if (search) {
+    qb.where('currency.baseCurrencyCode ILIKE :search', { search: `%${search}%` })
+      .orWhere('currency.targetCurrencyCode ILIKE :search', { search: `%${search}%` })
+      .orWhere('currency.provider ILIKE :search', { search: `%${search}%` });
+  }
+
+  const [data, total] = await qb
+    .skip((page - 1) * limit)
+    .take(limit)
+    .orderBy('currency.createdAt', 'DESC')
+    .getManyAndCount();
+
+  return { data, total, page, limit };
+}
 }

backend/src/currency-hub/dto/search-currency.dto.ts

@@ -0,0 +1,20 @@
+import { IsOptional, IsString, IsNumber, Min } from 'class-validator';
+import { Type } from 'class-transformer';
+
+export class SearchCurrencyDto {
+  @IsOptional()
+  @IsString()
+  search?: string;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsNumber()
+  @Min(1)
+  page?: number = 1;
+
+  @IsOptional()
+  @Type(() => Number)
+  @IsNumber()
+  @Min(1)
+  limit?: number = 10;
+}