package com.itstyle.quartz.dynamicquery;

import org.hibernate.query.internal.NativeQueryImpl;
import org.hibernate.transform.Transformers;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Repository;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import java.util.List;
/**
 * 动态jpql/nativesql查询的实现类
 * 创建者 张志朋
 * 创建时间	2018年3月8日
 */
@Repository
public class DynamicQueryImpl implements DynamicQuery {

	@PersistenceContext
	private EntityManager em;

	public EntityManager getEntityManager() {
		return em;
	}

	@Override
	public void save(Object entity) {
		em.persist(entity);
	}

	@Override
	public void update(Object entity) {
		em.merge(entity);
	}

	@Override
	public <T> void delete(Class<T> entityClass, Object entityid) {
		delete(entityClass, new Object[] { entityid });
	}

	@Override
	public <T> void delete(Class<T> entityClass, Object[] entityids) {
		for (Object id : entityids) {
			em.remove(em.getReference(entityClass, id));
		}
	}
	private Query createNativeQuery(String sql, Object... params) {
		Query q = em.createNativeQuery(sql);
		if (params != null && params.length > 0) {
			for (int i = 0; i < params.length; i++) {
				q.setParameter(i + 1, params[i]);
			}
		}
		return q;
	}
    private <T> Query createNativeQuery(Class<T> resultClass, String sql, Object... params) {
        Query q = em.createNativeQuery(sql);
        q.unwrap(NativeQueryImpl.class).setResultTransformer(Transformers.aliasToBean(resultClass));
        if(params!=null){
            for (int i = 0; i < params.length; i++) {
                q.setParameter(i + 1, params[i]);
            }
        }
        return q;
    }

	@Override
	public Long nativeQueryCount(String nativeSql, Object... params) {
		Object count = createNativeQuery(nativeSql, params).getSingleResult();
		return ((Number) count).longValue();
	}

    @Override
    public <T> List<T> nativeQueryPagingList(Class<T> resultClass, Pageable pageable, String nativeSql,
                                             Object... params) {
        Integer pageNumber = pageable.getPageNumber();
        Integer pageSize = pageable.getPageSize();
        Integer startPosition = pageNumber * pageSize;
        return createNativeQuery(resultClass, nativeSql, params).setFirstResult(startPosition).setMaxResults(pageSize)
                .getResultList();
    }

	public <T> List<T> nativeQueryList(Class<T> resultClass, String nativeSql,
											 Object... params) {
		return createNativeQuery(resultClass, nativeSql, params).getResultList();
	}
}