Add implementation of publication creation use case.

codiki-application/pom.xml

@@ -33,5 +33,15 @@
             <groupId>com.auth0</groupId>
             <artifactId>java-jwt</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

codiki-application/src/main/java/org/codiki/application/configuration/ServiceConfiguration.java

@@ -1,5 +1,7 @@
 package org.codiki.application.configuration;
 
+import java.time.Clock;
+
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
@@ -11,4 +13,9 @@ public class ServiceConfiguration {
     public PasswordEncoder passwordEncoder() {
         return new BCryptPasswordEncoder();
     }
+
+    @Bean
+    public Clock clock() {
+        return Clock.systemDefaultZone();
+    }
 }

codiki-application/src/main/java/org/codiki/application/publication/KeyGenerator.java

@@ -0,0 +1,23 @@
+package org.codiki.application.publication;
+
+import java.security.SecureRandom;
+
+import org.springframework.stereotype.Component;
+
+@Component
+public class KeyGenerator {
+    private static final String ALLOWED_CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+    private static final int KEY_LENGTH = 10;
+
+    public String generateKey() {
+        SecureRandom random = new SecureRandom();
+        StringBuilder code = new StringBuilder();
+
+        for (int i = 0; i < KEY_LENGTH; i++) {
+            int randomIndex = random.nextInt(ALLOWED_CHARACTERS.length());
+            code.append(ALLOWED_CHARACTERS.charAt(randomIndex));
+        }
+
+        return code.toString();
+    }
+}

codiki-application/src/main/java/org/codiki/application/publication/PublicationCreationRequestValidator.java

@@ -0,0 +1,26 @@
+package org.codiki.application.publication;
+
+import org.codiki.domain.publication.exception.PublicationCreationException;
+import org.codiki.domain.publication.model.PublicationCreationRequest;
+import org.springframework.stereotype.Component;
+
+@Component
+public class PublicationCreationRequestValidator {
+    void isValid(PublicationCreationRequest request) {
+        if (request.title() == null) {
+            throw new PublicationCreationException("title cannot be null.");
+        }
+
+        if (request.text() == null) {
+            throw new PublicationCreationException("text cannot be null.");
+        }
+
+        if (request.description() == null) {
+            throw new PublicationCreationException("description cannot be null.");
+        }
+
+        if (request.image() == null) {
+            throw new PublicationCreationException("image cannot be null.");
+        }
+    }
+}

codiki-application/src/main/java/org/codiki/application/publication/PublicationUseCases.java

@@ -0,0 +1,72 @@
+package org.codiki.application.publication;
+
+import java.time.Clock;
+import java.time.ZonedDateTime;
+import java.util.UUID;
+
+import static org.codiki.domain.publication.model.builder.AuthorBuilder.anAuthor;
+import static org.codiki.domain.publication.model.builder.PublicationBuilder.aPublication;
+import org.codiki.application.user.UserUseCases;
+import org.codiki.domain.category.model.Category;
+import org.codiki.domain.category.port.CategoryPort;
+import org.codiki.domain.exception.AuthenticationRequiredException;
+import org.codiki.domain.publication.exception.PublicationCreationException;
+import org.codiki.domain.publication.model.Publication;
+import org.codiki.domain.publication.model.PublicationCreationRequest;
+import org.codiki.domain.publication.port.PublicationPort;
+import org.codiki.domain.user.model.User;
+import org.springframework.stereotype.Service;
+
+@Service
+public class PublicationUseCases {
+    private final CategoryPort categoryPort;
+    private final KeyGenerator keyGenerator;
+    private final PublicationPort publicationPort;
+    private final PublicationCreationRequestValidator publicationCreationRequestValidator;
+    private final UserUseCases userUseCases;
+    private final Clock clock;
+
+    public PublicationUseCases(
+        CategoryPort categoryPort,
+        KeyGenerator keyGenerator,
+        PublicationPort publicationPort,
+        PublicationCreationRequestValidator publicationCreationRequestValidator,
+        UserUseCases userUseCases,
+        Clock clock
+    ) {
+        this.publicationCreationRequestValidator = publicationCreationRequestValidator;
+        this.userUseCases = userUseCases;
+        this.keyGenerator = keyGenerator;
+        this.clock = clock;
+        this.categoryPort = categoryPort;
+        this.publicationPort = publicationPort;
+    }
+
+    public Publication createPublication(PublicationCreationRequest request) {
+        publicationCreationRequestValidator.isValid(request);
+
+        User authenticatedUser = userUseCases.getAuthenticatedUser()
+            .orElseThrow(AuthenticationRequiredException::new);
+
+        Category category = categoryPort.findById(request.categoryId())
+            .orElseThrow(() -> new PublicationCreationException(
+                String.format("No any category exists for id %s", request.categoryId())
+            ));
+
+        Publication newPublication = aPublication()
+            .withId(UUID.randomUUID())
+            .withKey(keyGenerator.generateKey())
+            .withTitle(request.title())
+            .withText(request.text())
+            .withDescription(request.description())
+            .withImage(request.image())
+            .withCreationDate(ZonedDateTime.now(clock))
+            .withAuthor(anAuthor().basedOn(authenticatedUser).build())
+            .withCategory(category)
+            .build();
+
+        publicationPort.save(newPublication);
+
+        return newPublication;
+    }
+}

codiki-application/src/test/java/org/codiki/application/publication/KeyGeneratorTest.java

@@ -0,0 +1,31 @@
+package org.codiki.application.publication;
+
+import java.util.regex.Pattern;
+import java.util.stream.IntStream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class KeyGeneratorTest {
+    private KeyGenerator generator;
+
+    @BeforeEach
+    void setUp() {
+        generator = new KeyGenerator();
+    }
+
+    @Test
+    public void generateKey_should_generate_random_keys_with_alphanumeric_characters() {
+        Pattern validationRegex = Pattern.compile("^[0-9A-Z]{10}$");
+
+        IntStream.range(0, 1000)
+            .forEach(index -> {
+                String result = generator.generateKey();
+                assertThat(validationRegex.matcher(result).matches()).isTrue();
+            });
+    }
+
+
+
+}