Solved task

fullstack/task/packages/client/package.json

@@ -22,11 +22,14 @@
         "@types/react-dom": "18.0.6",
         "@types/styled-components": "^5.1.26",
         "@vitejs/plugin-react": "2.1.0",
+        "autoprefixer": "^10.4.21",
         "cross-env": "7.0.3",
         "eslint-import-resolver-typescript": "3.5.3",
         "eslint-plugin-import": "2.27.5",
         "eslint-plugin-react": "7.31.8",
         "jest": "28.1.3",
+        "postcss": "^8.5.3",
+        "tailwindcss": "^3.4.17",
         "ts-jest": "28.0.8",
         "vite": "3.1.0"
     },

fullstack/task/packages/client/postcss.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}

fullstack/task/packages/client/src/App.tsx

@@ -1,5 +1,14 @@
-function App() {
-    return <p>TODO</p>;
-}
+import React from 'react';
+import { ExchangeRates } from './components/ExchangeRates';
+
+const App: React.FC = () => {
+    return (
+        <div className="min-h-screen bg-blue-100 flex justify-center items-center p-4">
+            <div className="bg-white p-6 rounded-lg shadow-md max-w-4xl w-full">
+                <ExchangeRates />
+            </div>
+        </div>
+    );
+};
 
 export default App;

fullstack/task/packages/client/src/components/ExchangeRates.tsx

@@ -0,0 +1,87 @@
+import React from 'react';
+import { gql, useQuery } from '@apollo/client';
+
+interface ExchangeRate {
+    country: string;
+    currency: string;
+    amount: number;
+    code: string;
+    rate: number;
+}
+
+interface ExchangeRateData {
+    exchangeRates: {
+        fetchedAt: string;
+        rates: ExchangeRate[];
+    };
+}
+
+const EXCHANGE_RATES_QUERY = gql`
+    query GetExchangeRates {
+        exchangeRates {
+            fetchedAt
+            rates {
+                country
+                currency
+                amount
+                code
+                rate
+            }
+        }
+    }
+`;
+
+export const ExchangeRates: React.FC = () => {
+    const { loading, error, data } = useQuery<ExchangeRateData>(EXCHANGE_RATES_QUERY);
+    const timeSinceFetch = data
+        ? Math.floor(
+              (new Date().getTime() - new Date(data.exchangeRates.fetchedAt).getTime()) / 1000
+          )
+        : 0;
+
+    if (loading) return <div className="p-4 text-center">Loading...</div>;
+    if (error) return <div className="p-4 text-center text-red-500">Error: {error.message}</div>;
+
+    return (
+        <div className="w-full">
+            <h1 className="text-2xl font-bold mb-2">Exchange Rates</h1>
+            <p className="text-gray-600 mb-4">Last updated: {timeSinceFetch} seconds ago</p>
+            <div className="overflow-x-auto w-full">
+                <table className="w-full border-collapse">
+                    <thead>
+                        <tr>
+                            <th className="bg-gray-200 text-gray-700 font-semibold text-left p-3 border border-gray-300">
+                                Country
+                            </th>
+                            <th className="bg-gray-200 text-gray-700 font-semibold text-left p-3 border border-gray-300">
+                                Currency
+                            </th>
+                            <th className="bg-gray-200 text-gray-700 font-semibold text-left p-3 border border-gray-300">
+                                Amount
+                            </th>
+                            <th className="bg-gray-200 text-gray-700 font-semibold text-left p-3 border border-gray-300">
+                                Code
+                            </th>
+                            <th className="bg-gray-200 text-gray-700 font-semibold text-left p-3 border border-gray-300">
+                                Rate
+                            </th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        {data?.exchangeRates.rates.map((rate) => (
+                            <tr key={rate.code} className="hover:bg-blue-50">
+                                <td className="p-3 border border-gray-300">{rate.country}</td>
+                                <td className="p-3 border border-gray-300">{rate.currency}</td>
+                                <td className="p-3 border border-gray-300">{rate.amount}</td>
+                                <td className="p-3 border border-gray-300">{rate.code}</td>
+                                <td className="p-3 border border-gray-300 font-medium">
+                                    {rate.rate.toFixed(3)}
+                                </td>
+                            </tr>
+                        ))}
+                    </tbody>
+                </table>
+            </div>
+        </div>
+    );
+};

fullstack/task/packages/client/src/index.css

@@ -0,0 +1,3 @@
+@import 'tailwindcss/base';
+@import 'tailwindcss/components';
+@import 'tailwindcss/utilities';

fullstack/task/packages/client/src/main.tsx

@@ -2,9 +2,10 @@ import React from 'react';
 import ReactDOM from 'react-dom/client';
 import { ApolloClient, ApolloProvider, InMemoryCache } from '@apollo/client';
 import App from './App';
+import './index.css';
 
 const client = new ApolloClient({
-    uri: 'http://localhost:4000/graphql',
+    uri: 'http://localhost:4001/graphql',
     cache: new InMemoryCache(),
 });
 

fullstack/task/packages/client/tailwind.config.js

@@ -0,0 +1,10 @@
+module.exports = {
+  content: [
+    "./index.html",
+    "./src/**/*.{js,ts,jsx,tsx}",
+  ],
+  theme: {
+    extend: {},
+  },
+  plugins: [],
+}

fullstack/task/packages/server/.env

@@ -8,4 +8,6 @@ GQL_DEBUG=true
 GQL_PLAYGROUND=true
 GQL_INTROSPECTION=true
 
+BANK_URL=https://www.cnb.cz/cs/financni-trhy/devizovy-trh/kurzy-devizoveho-trhu/kurzy-devizoveho-trhu/denni_kurz.txt
+
 PORT=4001

fullstack/task/packages/server/schema.gql

@@ -17,8 +17,23 @@ A date-time string at UTC, such as 2019-12-03T09:54:33Z, compliant with the date
 """
 scalar DateTime
 
+type ExchangeRate {
+  id: ID!
+  country: String!
+  currency: String!
+  amount: Float!
+  code: String!
+  rate: Float!
+  createdAt: DateTime!
+}
+
+type ExchangeRateCache {
+  fetchedAt: DateTime!
+  rates: [ExchangeRate!]!
+}
+
 type Query {
-  exchangeRates: String!
+  exchangeRates: ExchangeRateCache!
   exampleByName(name: String!): Example
 }
 

fullstack/task/packages/server/src/entities/exchange-rate.entity.ts

@@ -0,0 +1,54 @@
+import { Field, Float, ID, ObjectType } from '@nestjs/graphql';
+import { IsNumber, IsString, MinLength } from 'class-validator';
+import { Column, Entity, Index, PrimaryGeneratedColumn } from 'typeorm';
+import { VAR_CHAR } from './constants';
+
+@ObjectType()
+@Entity()
+export class ExchangeRate {
+    @Field(() => ID)
+    @PrimaryGeneratedColumn('uuid')
+    public id!: string;
+
+    @IsString()
+    @MinLength(1)
+    @Field(() => String)
+    @Column({ ...VAR_CHAR })
+    public country!: string;
+
+    @IsString()
+    @MinLength(1)
+    @Field(() => String)
+    @Column({ ...VAR_CHAR })
+    public currency!: string;
+
+    @IsNumber()
+    @Field(() => Float)
+    @Column({ type: 'float' })
+    public amount!: number;
+
+    @IsString()
+    @MinLength(1)
+    @Field(() => String)
+    @Column({ ...VAR_CHAR })
+    @Index()
+    public code!: string;
+
+    @IsNumber()
+    @Field(() => Float)
+    @Column({ type: 'float' })
+    public rate!: number;
+
+    @Field(() => Date)
+    @Column({ type: 'timestamp' })
+    public createdAt!: Date;
+}
+
+@ObjectType()
+export class ExchangeRateCache {
+    @Field(() => Date)
+    public fetchedAt!: Date;
+
+    @Field(() => [ExchangeRate])
+    public rates!: ExchangeRate[];
+}

fullstack/task/packages/server/src/entities/index.ts

@@ -1 +1,2 @@
 export * from './example.entity';
+export * from './exchange-rate.entity';

fullstack/task/packages/server/src/migrations/1744935284746-add-exchange-rates.ts

@@ -0,0 +1,16 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class addExchangeRates1744935284746 implements MigrationInterface {
+    name = 'addExchangeRates1744935284746'
+
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`CREATE TABLE "exchange_rate" ("id" uuid NOT NULL DEFAULT uuid_generate_v4(), "country" character varying(255) NOT NULL, "currency" character varying(255) NOT NULL, "amount" double precision NOT NULL, "code" character varying(255) NOT NULL, "rate" double precision NOT NULL, "createdAt" TIMESTAMP NOT NULL, CONSTRAINT "PK_5c5d27d2b900ef6cdeef0398472" PRIMARY KEY ("id"))`);
+        await queryRunner.query(`CREATE INDEX "IDX_9c87dc76495d95ed8fd3a56809" ON "exchange_rate" ("code") `);
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`DROP INDEX "public"."IDX_9c87dc76495d95ed8fd3a56809"`);
+        await queryRunner.query(`DROP TABLE "exchange_rate"`);
+    }
+
+}

fullstack/task/packages/server/src/services/exchange-rate/exchange-rate.module.ts

@@ -1,9 +1,11 @@
 import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { ExchangeRate } from '../../entities';
 import { ExchangeRateService } from './exchange-rate.service';
 import { ExchangeRateResolver } from './exchange-rate.resolver';
 
 @Module({
-    imports: [],
+    imports: [TypeOrmModule.forFeature([ExchangeRate])],
     providers: [ExchangeRateService, ExchangeRateResolver],
     exports: [ExchangeRateService],
 })

fullstack/task/packages/server/src/services/exchange-rate/exchange-rate.resolver.ts

@@ -1,13 +1,13 @@
 import { Query, Resolver } from '@nestjs/graphql';
+import { ExchangeRateCache } from '../../entities';
 import { ExchangeRateService } from './exchange-rate.service';
 
 @Resolver()
 export class ExchangeRateResolver {
     constructor(private readonly exchangeRateService: ExchangeRateService) {}
 
-    // TODO: Implement a GraphQL Query that returns the exchange rates
-    @Query(() => String)
-    async exchangeRates(): Promise<string> {
-        return 'Hello';
+    @Query(() => ExchangeRateCache)
+    async exchangeRates(): Promise<ExchangeRateCache> {
+        return this.exchangeRateService.getExchangeRates();
     }
 }

fullstack/task/packages/server/src/services/exchange-rate/exchange-rate.service.ts

@@ -1,11 +1,58 @@
 import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import axios from 'axios';
+import { ConfigService } from '@nestjs/config';
+import { ExchangeRate, ExchangeRateCache } from '../../entities';
 
 @Injectable()
 export class ExchangeRateService {
-    public getExchangeRates = async () => {
-        // TODO: Implement the fetching and parsing of the exchange rates.
-        // Use this method in the resolver.
+    constructor(
+        @InjectRepository(ExchangeRate)
+        private readonly exchangeRateRepository: Repository<ExchangeRate>,
+        private readonly configService: ConfigService
+    ) {}
 
-        return [];
-    };
+    private async fetchFromCNB(): Promise<ExchangeRate[]> {
+        const bankUrl = this.configService.get<string>('BANK_URL') ?? '';
+        const response = await axios.get(bankUrl);
+        const lines = response.data.split('\n');
+        const rates = lines.slice(2).filter((line: string) => line.trim());
+
+        return rates.map((line: string) => {
+            const [country, currency, amount, code, rate] = line.split('|');
+            return {
+                country,
+                currency,
+                amount: parseFloat(amount),
+                code,
+                rate: parseFloat(rate.replace(',', '.')),
+                createdAt: new Date(),
+            } as ExchangeRate;
+        });
+    }
+
+    public async getExchangeRates(): Promise<ExchangeRateCache> {
+        const latestRates = await this.exchangeRateRepository.find({
+            order: { createdAt: 'DESC' },
+        });
+        if (
+            latestRates.length > 0 &&
+            new Date().getTime() - new Date(latestRates[0].createdAt).getTime() < 5 * 60 * 1000
+        ) {
+            return {
+                fetchedAt: latestRates[0].createdAt,
+                rates: latestRates,
+            };
+        }
+
+        const freshRates = await this.fetchFromCNB();
+        await this.exchangeRateRepository.clear();
+        const savedRates = await this.exchangeRateRepository.save(freshRates);
+
+        return {
+            fetchedAt: new Date(),
+            rates: savedRates,
+        };
+    }
 }