package org.hibernate.bugs;

import static org.assertj.core.api.Assertions.assertThat;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Persistence;
import javax.persistence.Query;

import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggingEvent;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * This template demonstrates how to develop a test case for Hibernate ORM, using the Java Persistence API.
 */
public class JPAUnitTestCase {

  private EntityManagerFactory entityManagerFactory;
  private Logger sqlLogger;
  private Level initialSqlLevel;

  @Before
  public void init() {
    sqlLogger = Logger.getLogger("org.hibernate.SQL");
    initialSqlLevel = sqlLogger.getLevel();
    sqlLogger.setLevel(Level.DEBUG);
    entityManagerFactory = Persistence.createEntityManagerFactory("templatePU");
  }

  @After
  public void destroy() {
    entityManagerFactory.close();
    sqlLogger.setLevel(initialSqlLevel);
  }

  // Entities are auto-discovered, so just add them anywhere on class-path
  // Add your tests, using standard JUnit.
  @Test
  public void hhh123Test() throws Exception {
    EntityManager entityManager = entityManagerFactory.createEntityManager();
    int numberOfParents = 5;

    runInTransaction(entityManager, () -> {
      for (int id = 0; id < numberOfParents; id++) {
        Parent parent = new Parent(id);
        new Child(id + 100, parent);
        entityManager.persist(parent);
      }
    });

    runInTransaction(entityManager, () -> {
      RecordingLog4jAppender appender = new RecordingLog4jAppender();
      sqlLogger.addAppender(appender);

      Query query = entityManager.createQuery("from " + Parent.class.getSimpleName());
      @SuppressWarnings("unchecked")
      List<Parent> parents = query.getResultList();
      sqlLogger.removeAppender(appender);
      assertThat(parents).hasSize(numberOfParents);
      assertThat(appender.getLogEvents()).size().isLessThan(numberOfParents);
    });

    entityManager.close();
  }

  private void runInTransaction(EntityManager entityManager, Runnable runnable) {
    entityManager.getTransaction().begin();
    runnable.run();
    entityManager.getTransaction().commit();
    entityManager.clear();
  }
}


@Entity
class Parent {
  @Id
  private long id;

  @OneToOne(mappedBy = "parent", optional = false, cascade = CascadeType.ALL, fetch = FetchType.LAZY)
  private Child child;

  Parent() {}

  public Parent(long id) {
    this.id = id;
  }

  void setChild(Child child) {
    this.child = child;
  }

  @Override
  public String toString() {
    return "Parent [id=" + id + ", child=" + child + "]";
  }
}


@Entity
class Child {
  @Id
  private long id;

  @OneToOne(optional = false, fetch = FetchType.LAZY)
  private Parent parent;

  Child() {}

  public Child(long id, Parent parent) {
    this.id = id;
    setParent(parent);
  }

  public void setParent(Parent parent) {
    this.parent = parent;
    parent.setChild(this);
  }

  @Override
  public String toString() {
    return "Child [id=" + id + "]";
  }
}


class RecordingLog4jAppender extends AppenderSkeleton {
  private final List<LoggingEvent> logEvents = new ArrayList<>();
  private boolean active = true;

  @Override
  public boolean requiresLayout() {
    return false;
  }

  @Override
  protected void append(LoggingEvent loggingEvent) {
    if (active) {
      logEvents.add(loggingEvent);
    }
  }

  @Override
  public void close() {}

  public void setActive(boolean value) {
    active = value;
  }

  public void clear() {
    logEvents.clear();
  }

  public List<LoggingEvent> getLogEvents() {
    return Collections.unmodifiableList(logEvents);
  }
}