package authoringtool.persistence.changelog.java;

import authoringtool.common.helpers.ValidationHelper;
import authoringtool.persistence.encryption.StringEncryptor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import persistence.dao.EntityManagerHolder;

import javax.persistence.EntityManager;
import javax.persistence.Query;
import java.lang.reflect.Field;
import java.util.List;

public class EncryptionHelper {

    private static final Log log = LogFactory.getLog(StringEncryptor.class);
    public static final String UUID = "uuid";

    public static <T> void executeEncryption(String selectQuery,
                                             String updateQuery, String tupleName) {
        try {
            EntityManager em = EntityManagerHolder.getCurrentEntityManager();

            @SuppressWarnings("unchecked")
            List<T> results = em.createNativeQuery(selectQuery, tupleName).getResultList();

            Query update = em.createNativeQuery(updateQuery);
            if (!ValidationHelper.isNullOrEmpty(results)) {
                for (T t : results) {
                    //Setting query params by reflexively-obtained tuple field values
                    for (Field field : t.getClass().getDeclaredFields()) {
                        field.setAccessible(true);
                        String value = UUID.equals(field.getName()) ?
                                (String) field.get(t) :
                                StringEncryptor.getInstance().encrypt((String) field.get(t));
                        update.setParameter(field.getName(), value);
                    }
                    update.executeUpdate();
                }
            }
        } catch (IllegalAccessException e) {
            log.error(e);
            e.printStackTrace();
        }
    }
}