yaperos · locobenjas · Mar 2, 2026
diff --git a/README.md b/README.md
@@ -1,82 +1,145 @@
-# Yape Code Challenge :rocket:
+# Reto Yape
 
-Our code challenge will let you marvel us with your Jedi coding skills :smile:. 
+## Arquitectura
 
-Don't forget that the proper way to submit your work is to fork the repo and create a PR :wink: ... have fun !!
-
-- [Problem](#problem)
-- [Tech Stack](#tech_stack)
-- [Send us your challenge](#send_us_your_challenge)
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                     transaction-service                          │
+│                                                                  │
+│  REST API  ──►  CreateTransactionUseCase  ──►  DB (PENDING)     │
+│                          │                                       │
+│                          └──► Kafka: transaction.created        │
+│                                                                  │
+│  Kafka Consumer ◄── transaction.status.updated                  │
+│          │                                                       │
+│          └──► UpdateTransactionStatusUseCase ──► DB (update)    │
+└─────────────────────────────────────────────────────────────────┘
+                              ▲ │
+                              │ ▼ Kafka
+┌─────────────────────────────────────────────────────────────────┐
+│                     anti-fraud-service                           │
+│                                                                  │
+│  Kafka Consumer ◄── transaction.created                         │
+│          │                                                       │
+│          └──► EvaluateTransactionUseCase                        │
+│                  value > 1000 → REJECTED                        │
+│                  value ≤ 1000 → APPROVED                        │
+│                          │                                       │
+│                          └──► Kafka: transaction.status.updated │
+└─────────────────────────────────────────────────────────────────┘
+```
 
-# Problem
+## Estructura de paquetes - Arquitectura Hexagonal
 
-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:
+```
+src/main/java/com/yape/transaction/
+├── domain/
+│   ├── model/                    # Entidades y Value Objects (núcleo del dominio)
+│   │   ├── Transaction.java
+│   │   ├── TransactionStatus.java
+│   │   └── TransactionType.java
+│   └── port/
+│       ├── in/                   # Casos de uso (interfaces de entrada)
+│       │   ├── CreateTransactionUseCase.java
+│       │   ├── GetTransactionUseCase.java
+│       │   └── UpdateTransactionStatusUseCase.java
+│       └── out/                  # Puertos de salida (contratos de infraestructura)
+│           ├── TransactionRepository.java
+│           └── TransactionEventPublisher.java
+├── application/
+│   └── usecase/                  # Implementaciones de casos de uso
+│       ├── CreateTransactionService.java
+│       ├── GetTransactionService.java
+│       └── UpdateTransactionStatusService.java
+└── infrastructure/
+    ├── adapter/
+    │   ├── in/
+    │   │   ├── rest/             # Controllers REST (adaptador de entrada)
+    │   │   └── messaging/        # Kafka consumers (adaptador de entrada)
+    │   └── out/
+    │       ├── persistence/      # JPA adapters (adaptador de salida)
+    │       └── messaging/        # Kafka producers (adaptador de salida)
+    └── config/                   # Configuración de Spring / Kafka
+```
 
-<ol>
-  <li>pending</li>
-  <li>approved</li>
-  <li>rejected</li>  
-</ol>
+## Cómo levantar el proyecto
 
-Every transaction with a value greater than 1000 should be rejected.
+### Prerrequisitos
+- Docker & Docker Compose
+- Java 17+
+- Maven 3.9+
 
-```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)]
+### Levantar infraestructura + servicios
+```bash
+docker-compose up -d
 ```
 
-# Tech Stack
+### Solo infraestructura (para desarrollo local)
+```bash
+docker-compose up -d postgres kafka zookeeper kafka-ui
+```
 
-<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>
+### Ejecutar servicios localmente
+```bash
+# Terminal 1 - Transaction Service
+cd transaction-service
+mvn spring-boot:run
 
-We do provide a `Dockerfile` to help you get started with a dev environment.
+# Terminal 2 - Anti-Fraud Service
+cd anti-fraud-service
+mvn spring-boot:run
+```
 
-You must have two resources:
+## API Endpoints
 
-1. Resource to create a transaction that must containt:
+### Crear transacción
+```http
+POST http://localhost:8080/api/v1/transactions
+Content-Type: application/json
 
-```json
 {
-  "accountExternalIdDebit": "Guid",
-  "accountExternalIdCredit": "Guid",
+  "accountExternalIdDebit": "3a0c1b2d-4e5f-6789-abcd-ef0123456789",
+  "accountExternalIdCredit": "7f8e9d0c-1b2a-3456-789a-bcdef0123456",
   "tranferTypeId": 1,
   "value": 120
 }
 ```
 
-2. Resource to retrieve a transaction
+### Recuperar transacción
+```http
+GET http://localhost:8080/api/v1/transactions/{transactionExternalId}
+```
 
+### Respuesta esperada
 ```json
 {
-  "transactionExternalId": "Guid",
-  "transactionType": {
-    "name": ""
-  },
-  "transactionStatus": {
-    "name": ""
-  },
+  "transactionExternalId": "uuid",
+  "transactionType": { "name": "Transfer" },
+  "transactionStatus": { "name": "APPROVED" },
   "value": 120,
-  "createdAt": "Date"
+  "createdAt": "2024-01-15T10:30:00"
 }
 ```
 
-## Optional
+## Tópicos Kafka
 
-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?
+| Tópico                        | Publicado por         | Consumido por         |
+|-------------------------------|-----------------------|-----------------------|
+| `transaction.created`         | transaction-service   | anti-fraud-service    |
+| `transaction.status.updated`  | anti-fraud-service    | transaction-service   |
 
-You can use Graphql;
+## Reglas de negocio
 
-# Send us your challenge
+- Toda transacción inicia con estado **PENDING**
+- Anti-fraud aprueba si `value <= 1000`
+- Anti-fraud rechaza si `value > 1000`
 
-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.
+## Tests
 
-If you have any questions, please let us know.
+```bash
+# Transaction service
+cd transaction-service && mvn test
+
+# Anti-fraud service
+cd anti-fraud-service && mvn test
+```
diff --git a/anti-fraud-service/Dockerfile b/anti-fraud-service/Dockerfile
@@ -0,0 +1,12 @@
+FROM maven:3.9-eclipse-temurin-17-alpine AS build
+WORKDIR /app
+COPY pom.xml .
+RUN mvn dependency:go-offline -B
+COPY src ./src
+RUN mvn clean package -DskipTests
+
+FROM eclipse-temurin:17-jre-alpine
+WORKDIR /app
+COPY --from=build /app/target/*.jar app.jar
+EXPOSE 8081
+ENTRYPOINT ["java", "-jar", "app.jar"]
diff --git a/anti-fraud-service/pom.xml b/anti-fraud-service/pom.xml
@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.2.0</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.yape</groupId>
+    <artifactId>anti-fraud-service</artifactId>
+    <version>1.0.0</version>
+    <name>anti-fraud-service</name>
+
+    <properties>
+        <java.version>17</java.version>
+    </properties>
+
+    <dependencies>
+        <!-- Kafka -->
+        <dependency>
+            <groupId>org.springframework.kafka</groupId>
+            <artifactId>spring-kafka</artifactId>
+        </dependency>
+
+        <!-- Spring Boot base (necesario para el contexto) -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+        </dependency>
+
+        <!-- Actuator -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-actuator</artifactId>
+        </dependency>
+
+        <!-- Test -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.kafka</groupId>
+            <artifactId>spring-kafka-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/anti-fraud-service/src/main/java/com/yape/antifraud/AntiFraudApplication.java b/anti-fraud-service/src/main/java/com/yape/antifraud/AntiFraudApplication.java
@@ -0,0 +1,12 @@
+package com.yape.antifraud;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class AntiFraudApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(AntiFraudApplication.class, args);
+    }
+}
diff --git a/...vice/src/main/java/com/yape/antifraud/application/usecase/EvaluateTransactionService.java b/...vice/src/main/java/com/yape/antifraud/application/usecase/EvaluateTransactionService.java
@@ -0,0 +1,35 @@
+package com.yape.antifraud.application.usecase;
+
+import com.yape.antifraud.domain.model.FraudEvaluation;
+import com.yape.antifraud.domain.port.in.EvaluateTransactionUseCase;
+import com.yape.antifraud.domain.port.out.FraudResultPublisher;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Service;
+
+@Service
+public class EvaluateTransactionService implements EvaluateTransactionUseCase {
+
+    private static final Logger log = LoggerFactory.getLogger(EvaluateTransactionService.class);
+
+    private final FraudResultPublisher fraudResultPublisher;
+
+    public EvaluateTransactionService(FraudResultPublisher fraudResultPublisher) {
+        this.fraudResultPublisher = fraudResultPublisher;
+    }
+
+    @Override
+    public FraudEvaluation execute(Command command) {
+        FraudEvaluation evaluation = new FraudEvaluation(
+                command.transactionExternalId(),
+                command.value()
+        ).evaluate();
+
+        log.info("Transaction {} evaluated as {} (value: {})",
+                command.transactionExternalId(), evaluation.getResult(), command.value());
+
+        fraudResultPublisher.publishResult(evaluation);
+
+        return evaluation;
+    }
+}
diff --git a/anti-fraud-service/src/main/java/com/yape/antifraud/domain/model/FraudEvaluation.java b/anti-fraud-service/src/main/java/com/yape/antifraud/domain/model/FraudEvaluation.java
@@ -0,0 +1,35 @@
+package com.yape.antifraud.domain.model;
+
+import java.math.BigDecimal;
+import java.util.UUID;
+
+public class FraudEvaluation {
+
+    private static final BigDecimal MAX_ALLOWED_VALUE = BigDecimal.valueOf(1000);
+
+    private final UUID transactionExternalId;
+    private final BigDecimal value;
+    private FraudResult result;
+
+    public FraudEvaluation(UUID transactionExternalId, BigDecimal value) {
+        this.transactionExternalId = transactionExternalId;
+        this.value = value;
+    }
+
+    /**
+     * Core business rule: transactions over 1000 are rejected
+     * This is a pure domain method — no infrastructure concerns
+     */
+    public FraudEvaluation evaluate() {
+        this.result = value.compareTo(MAX_ALLOWED_VALUE) > 0
+                ? FraudResult.REJECTED
+                : FraudResult.APPROVED;
+        return this;
+    }
+
+    public UUID getTransactionExternalId() { return transactionExternalId; }
+    public BigDecimal getValue() { return value; }
+    public FraudResult getResult() { return result; }
+    public boolean isApproved() { return FraudResult.APPROVED.equals(result); }
+    public boolean isRejected() { return FraudResult.REJECTED.equals(result); }
+}
diff --git a/anti-fraud-service/src/main/java/com/yape/antifraud/domain/model/FraudResult.java b/anti-fraud-service/src/main/java/com/yape/antifraud/domain/model/FraudResult.java
@@ -0,0 +1,6 @@
+package com.yape.antifraud.domain.model;
+
+public enum FraudResult {
+    APPROVED,
+    REJECTED
+}
diff --git a/...d-service/src/main/java/com/yape/antifraud/domain/port/in/EvaluateTransactionUseCase.java b/...d-service/src/main/java/com/yape/antifraud/domain/port/in/EvaluateTransactionUseCase.java
@@ -0,0 +1,13 @@
+package com.yape.antifraud.domain.port.in;
+
+import com.yape.antifraud.domain.model.FraudEvaluation;
+
+import java.math.BigDecimal;
+import java.util.UUID;
+
+public interface EvaluateTransactionUseCase {
+
+    FraudEvaluation execute(Command command);
+
+    record Command(UUID transactionExternalId, BigDecimal value) {}
+}
diff --git a/...-fraud-service/src/main/java/com/yape/antifraud/domain/port/out/FraudResultPublisher.java b/...-fraud-service/src/main/java/com/yape/antifraud/domain/port/out/FraudResultPublisher.java
@@ -0,0 +1,8 @@
+package com.yape.antifraud.domain.port.out;
+
+import com.yape.antifraud.domain.model.FraudEvaluation;
+
+public interface FraudResultPublisher {
+
+    void publishResult(FraudEvaluation evaluation);
+}