Solucion de challenge

.gitignore

@@ -102,3 +102,6 @@ dist
 
 # TernJS port file
 .tern-port
+
+#package-lock.json
+package-lock.json

README.md

@@ -1,82 +1,148 @@
-# Yape Code Challenge :rocket:
+# app-nodejs-codechallenge
 
-Our code challenge will let you marvel us with your Jedi coding skills :smile:. 
+Este repositorio es un microservicio en NestJS para manejar transacciones financieras. Usa PostgreSQL para persistencia y Kafka para la validación asíncrona (anti-fraud).
 
-Don't forget that the proper way to submit your work is to fork the repo and create a PR :wink: ... have fun !!
+Este README describe cómo levantar el entorno, cómo usar los servicios (endpoints) y cómo comprobar el flujo de mensajes con Kafka.
 
-- [Problem](#problem)
-- [Tech Stack](#tech_stack)
-- [Send us your challenge](#send_us_your_challenge)
+## Resumen técnico
+- Framework: NestJS
+- Persistencia: PostgreSQL (TypeORM)
+- Mensajería: Kafka
+- Arquitectura: monolito modular con flujo event-driven para validación anti-fraud
 
-# Problem
+## Requisitos
+- Docker & Docker Compose
+- Node 18+ y npm o yarn
 
-Every time a financial transaction is created it must be validated by our anti-fraud microservice and then the same service sends a message back to update the transaction status.
-For now, we have only three transaction statuses:
+## Configuración (.env)
+Crear un archivo `.env` en la raíz con las variables de Postgres:
 
-<ol>
-  <li>pending</li>
-  <li>approved</li>
-  <li>rejected</li>  
-</ol>
+```
+POSTGRES_HOST=localhost
+POSTGRES_PORT=5432
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=postgres
+POSTGRES_DB=postgres
+```
+
+Nota: la app por defecto usa `localhost:9092` como broker Kafka. Si ejecutas la app dentro de Docker, usa `kafka:29092` como broker.
+
+## Levantar el entorno
 
-Every transaction with a value greater than 1000 should be rejected.
+1. Instala dependencias:
 
-```mermaid
-  flowchart LR
-    Transaction -- Save Transaction with pending Status --> transactionDatabase[(Database)]
-    Transaction --Send transaction Created event--> Anti-Fraud
-    Anti-Fraud -- Send transaction Status Approved event--> Transaction
-    Anti-Fraud -- Send transaction Status Rejected event--> Transaction
-    Transaction -- Update transaction Status event--> transactionDatabase[(Database)]
+```bash
+npm install
+# o
+yarn install
 ```
 
-# Tech Stack
+2. Levanta infra con Docker Compose (Postgres, Zookeeper, Kafka):
 
-<ol>
-  <li>Node. You can use any framework you want (i.e. Nestjs with an ORM like TypeOrm or Prisma) </li>
-  <li>Any database</li>
-  <li>Kafka</li>    
-</ol>
+```bash
+docker compose up -d
+```
 
-We do provide a `Dockerfile` to help you get started with a dev environment.
+3. Ejecuta la aplicación en modo desarrollo:
 
-You must have two resources:
+```bash
+npm run local
+# o
+yarn local
+```
 
-1. Resource to create a transaction that must containt:
+### Levantar los dos servicios (transaction + anti-fraud)
 
-```json
-{
-  "accountExternalIdDebit": "Guid",
-  "accountExternalIdCredit": "Guid",
-  "tranferTypeId": 1,
-  "value": 120
-}
+Abre dos terminales separados y en cada uno ejecuta:
+
+Terminal A (transaction):
+
+```bash
+cd transaction
+npm install
+npm run local
+```
+
+Terminal B (anti-fraud):
+
+```bash
+cd anti-fraud
+npm install
+npm run local
 ```
 
-2. Resource to retrieve a transaction
+Ambos servicios deben poder conectar al broker Kafka que levantaste con `docker compose up -d`.
+
+## Cómo usar los servicios (endpoints)
+
+Base URL: `http://localhost:3000`
+
+1) Crear transacción — POST `/transaction`
+
+- Descripción: crea una transacción y publica el evento para validación anti-fraud.
+- Body (JSON):
 
 ```json
 {
-  "transactionExternalId": "Guid",
-  "transactionType": {
-    "name": ""
-  },
-  "transactionStatus": {
-    "name": ""
-  },
-  "value": 120,
-  "createdAt": "Date"
+	"accountExternalIdDebit": "5429d629-c239-45fa-8235-1a386258c536",
+	"accountExternalIdCredit": "d6cd54da-8ce3-4f79-abda-bd5be9b19e68",
+	"tranferTypeId": 1,
+	"value": 120
 }
 ```
 
-## Optional
+Ejemplos `curl`:
+
+```bash
+curl -i -X POST http://localhost:3000/transaction \
+	-H "Content-Type: application/json" \
+	-d '{
+		"accountExternalIdDebit": "5429d629-c239-45fa-8235-1a386258c536",
+		"accountExternalIdCredit": "d6cd54da-8ce3-4f79-abda-bd5be9b19e68",
+		"tranferTypeId": 1,
+		"value": 120
+	}'
+```
+
+2) Listar transacciones — GET `/transaction`
 
-You can use any approach to store transaction data but you should consider that we may deal with high volume scenarios where we have a huge amount of writes and reads for the same data at the same time. How would you tackle this requirement?
+- Descripción: devuelve todas las transacciones guardadas (útil para debug local).
 
-You can use Graphql;
+```bash
+curl http://localhost:3000/transaction
+```
 
-# Send us your challenge
+## Flujo Kafka (anti-fraud)
 
-When you finish your challenge, after forking a repository, you **must** open a pull request to our repository. There are no limitations to the implementation, you can follow the programming paradigm, modularization, and style that you feel is the most appropriate solution.
+- Al crear una transacción se publica un evento `transaction.created` con los datos básicos.
+- Un consumidor (anti-fraud) valida la transacción y emite `transaction.validated` con `{ id, status }`.
+- La app escucha `transaction.validated` y actualiza el `status` en la base de datos.
+
+Regla implementada en el anti-fraud (ejemplo): `if value > 1000 => rejected`; else `approved`.
+
+3. Consultar la última transacción:
+
+```sql
+select * from transaction where "accountExternalIdDebit" = {{ID}};
+```
+
+## DDL (esquema) para probar localmente
+
+```sql
+
+CREATE TABLE public.transaction
+(
+	"accountExternalIdDebit"  varchar                              NOT NULL,
+	"accountExternalIdCredit" varchar                              NOT NULL,
+	"tranferTypeId"           integer                              NOT NULL,
+	value                     numeric                              NOT NULL,
+	id                        uuid      DEFAULT uuid_generate_v4() NOT NULL
+		CONSTRAINT "PK_89eadb93a89810556e1cbcd6ab9"
+			PRIMARY KEY,
+	"createdAt"               timestamp DEFAULT now()              NOT NULL,
+	"updatedAt"               timestamp DEFAULT now()              NOT NULL,
+	status                    integer                              NOT NULL
+);
+```
 
-If you have any questions, please let us know.
+Si usas TypeORM, la entidad del proyecto crea automáticamente la tabla al iniciar (si `synchronize: true`). Usa este DDL solo si quieres preparar la tabla manualmente o probar fuera del ciclo de arranque de la app.

anti-fraud/.eslintrc.js

@@ -0,0 +1,25 @@
+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    tsconfigRootDir: __dirname,
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint/eslint-plugin'],
+  extends: [
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  ignorePatterns: ['.eslintrc.js'],
+  rules: {
+    '@typescript-eslint/interface-name-prefix': 'off',
+    '@typescript-eslint/explicit-function-return-type': 'off',
+    '@typescript-eslint/explicit-module-boundary-types': 'off',
+    '@typescript-eslint/no-explicit-any': 'off',
+  },
+};

anti-fraud/.prettierrc

@@ -0,0 +1,4 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all"
+}

anti-fraud/nest-cli.json

@@ -0,0 +1,8 @@
+{
+  "$schema": "https://json.schemastore.org/nest-cli",
+  "collection": "@nestjs/schematics",
+  "sourceRoot": "src",
+  "compilerOptions": {
+    "deleteOutDir": true
+  }
+}

anti-fraud/package.json

@@ -0,0 +1,77 @@
+{
+  "name": "anti-fraud",
+  "version": "0.0.1",
+  "description": "",
+  "author": "",
+  "private": true,
+  "license": "UNLICENSED",
+  "scripts": {
+    "build": "nest build",
+    "format": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",
+    "start": "nest start",
+    "local": "nest start --watch",
+    "start:debug": "nest start --debug --watch",
+    "start:prod": "node dist/main",
+    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
+    "test": "jest",
+    "test:watch": "jest --watch",
+    "test:cov": "jest --coverage",
+    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
+    "test:e2e": "jest --config ./test/jest-e2e.json"
+  },
+  "dependencies": {
+    "@nestjs/common": "^10.0.0",
+    "@nestjs/config": "^4.0.2",
+    "@nestjs/core": "^10.0.0",
+    "@nestjs/microservices": "^10.4.18",
+    "@nestjs/platform-express": "^10.0.0",
+    "@nestjs/typeorm": "^11.0.0",
+    "class-transformer": "^0.5.1",
+    "class-validator": "^0.14.2",
+    "kafkajs": "^2.2.4",
+    "pg": "^8.16.0",
+    "reflect-metadata": "^0.2.0",
+    "rxjs": "^7.8.1",
+    "typeorm": "^0.3.24"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "^10.0.0",
+    "@nestjs/schematics": "^10.0.0",
+    "@nestjs/testing": "^10.0.0",
+    "@types/express": "^5.0.0",
+    "@types/jest": "^29.5.2",
+    "@types/node": "^20.3.1",
+    "@types/supertest": "^6.0.0",
+    "@typescript-eslint/eslint-plugin": "^8.0.0",
+    "@typescript-eslint/parser": "^8.0.0",
+    "eslint": "^8.0.0",
+    "eslint-config-prettier": "^9.0.0",
+    "eslint-plugin-prettier": "^5.0.0",
+    "jest": "^29.5.0",
+    "prettier": "^3.0.0",
+    "source-map-support": "^0.5.21",
+    "supertest": "^7.0.0",
+    "ts-jest": "^29.1.0",
+    "ts-loader": "^9.4.3",
+    "ts-node": "^10.9.1",
+    "tsconfig-paths": "^4.2.0",
+    "typescript": "^5.1.3"
+  },
+  "jest": {
+    "moduleFileExtensions": [
+      "js",
+      "json",
+      "ts"
+    ],
+    "rootDir": "src",
+    "testRegex": ".*\\.spec\\.ts$",
+    "transform": {
+      "^.+\\.(t|j)s$": "ts-jest"
+    },
+    "collectCoverageFrom": [
+      "**/*.(t|j)s"
+    ],
+    "coverageDirectory": "../coverage",
+    "testEnvironment": "node"
+  }
+}

anti-fraud/src/app.controller.ts

@@ -0,0 +1,17 @@
+import { Controller, Logger } from '@nestjs/common';
+import { MessagePattern, Payload } from '@nestjs/microservices';
+import { AppService } from './app.service';
+import { TransactionCreatedEvent } from './models/transaction-created.event';
+
+@Controller()
+export class AppController {
+  constructor(private readonly appService: AppService) {}
+
+  @MessagePattern('transaction.created')
+  async approvedTransaction(
+    @Payload() payload: TransactionCreatedEvent,
+  ): Promise<void> {
+    Logger.debug(payload);
+    await this.appService.evaluateTransaction(payload);
+  }
+}

anti-fraud/src/app.module.ts

@@ -0,0 +1,29 @@
+import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import { ClientsModule, Transport } from '@nestjs/microservices';
+import { AppController } from './app.controller';
+import { AppService } from './app.service';
+
+@Module({
+  imports: [
+    ConfigModule.forRoot(),
+    ClientsModule.register([
+      {
+        name: 'KAFKA',
+        transport: Transport.KAFKA,
+        options: {
+          client: {
+            clientId: 'anti-fraud',
+            brokers: [`${process.env.KAFKA_HOST}:9092`],
+          },
+          consumer: {
+            groupId: 'anti-fraud-consumer',
+          },
+        },
+      },
+    ]),
+  ],
+  controllers: [AppController],
+  providers: [AppService]
+})
+export class AppModule { }