package com.yihu.mysql.query;

import com.yihu.utils.context.SpringContextUtils;
import org.hibernate.Query;
import org.hibernate.Session;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.CrudRepository;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import javax.persistence.metamodel.EntityType;
import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.text.ParseException;
import java.util.*;

/**
 * Service基础类。此类基于Spring Data JPA进行封装（Spring Data JPA又是基于JPA封装，EHR平台使用Hibernate作为JPA实现者）。
 * 需要注意的是，部分功能会跳过JPA接口而直接使用Hibernate接口，比如访问Hibernate的Session接口，因为它把JPA的EntityManager功能强大。
 *
 * @author lincl
 * @author Sand
 * @version 1.0
 * @created 2016.2.3。
 */
@Transactional(propagation = Propagation.SUPPORTS)
public abstract class BaseJpaService<T, R extends CrudRepository> {

    protected final int defaultPage = 1;
    protected final int defaultSize = 15;

    protected Class<T> tClass;
    protected Class<R> repoClass;

    @PersistenceContext
    protected EntityManager entityManager;
    @Autowired
    protected JdbcTemplate jdbcTemplate;

    public BaseJpaService() {
        Type genType = getClass().getGenericSuperclass();
        if (genType instanceof ParameterizedType) {
            Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
            if (params.length == 2) {
                tClass = (Class<T>) params[0];
                repoClass = (Class<R>) params[1];
            }
        }
    }

    public T save (T entity) {
        return (T) getRepository().save(entity);
    }

    public void batchInsert (List list) {
        for (int i = 0; i < list.size(); i++) {
            entityManager.persist(list.get(i));
            if (i % 30 == 0) {
                entityManager.flush();
                entityManager.clear();
            }
        }
    }

    public void delete(Serializable id) {
        getRepository().delete(id);
    }

    public void delete(T entity) {
        getRepository().delete(entity);
    }

    public void delete(Iterable ids) {
        getRepository().delete(ids);
    }

    public int delete(Object[] ids){
        if (Integer.class.getName().equals(getEntityIdType())) {
            Integer [] _ids = new Integer[ids.length];
            for (int i = 0; i < ids.length; i ++) {
                _ids[i] = new Integer(ids[i].toString());
            }
            ids = _ids;
        }
        String hql = "DELETE FROM " + getEntityClass().getName() + " WHERE " + getEntityIdFiled() + " in(:ids)";
        Query query = currentSession().createQuery(hql);
        query.setParameterList("ids", ids);
        return query.executeUpdate();
    }

    public T retrieve(Serializable id) {
        return (T) getRepository().findOne(id);
    }

    public List<T> search(String filters) throws ParseException {
        URLQueryParser queryParser = createQueryParser("", filters, "");
        CriteriaQuery query = queryParser.makeCriteriaQuery();

        return entityManager
                .createQuery(query)
                .getResultList();
    }

    public List<T> search(String filters, String sorts) throws ParseException {
        URLQueryParser queryParser = createQueryParser("", filters, sorts);
        CriteriaQuery query = queryParser.makeCriteriaQuery();

        return entityManager
                .createQuery(query)
                .getResultList();
    }

    public List<T> search(String fields, String filters, String sorts) throws ParseException {
        URLQueryParser queryParser = createQueryParser(fields, filters, sorts);
        CriteriaQuery query = queryParser.makeCriteriaQuery();
        return entityManager
                .createQuery(query)
                .getResultList();
    }

    public List<T> search(String fields, String filters, String sorts, Integer page, Integer size) throws ParseException {
        URLQueryParser queryParser = createQueryParser(fields, filters, sorts);
        CriteriaQuery query = queryParser.makeCriteriaQuery();
        if (page == null || page <= 0) {
            page = defaultPage;
        }
        if (size == null || size <= 0 || size > 10000) {
            size = defaultSize;
        }
        return entityManager
                .createQuery(query)
                .setFirstResult((page - 1) * size)
                .setMaxResults(size)
                .getResultList();
    }

    public List<T> findByField(String field, Object value){

        return findByFields(
                new String[]{field},
                new Object[]{value}
        );
    }

    public List<T> findByFields(String[] fields, Object[] values){
        CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
        CriteriaQuery query = criteriaBuilder.createQuery(getEntityClass());
        Root<T> root = query.from(getEntityClass());
        List<Predicate> ls = new ArrayList<>();
        for(int i=0; i< fields.length; i++){
            if (values[i].getClass().isArray()) {
                ls.add(criteriaBuilder.in(root.get(fields[i]).in((Object[]) values[i])));
            } else {
                ls.add(criteriaBuilder.equal(root.get(fields[i]), values[i]));
            }
        }
        query.where(ls.toArray(new Predicate[ls.size()]));
        return entityManager
                .createQuery(query)
                .getResultList() ;
    }

    public long getCount(String filters) throws ParseException {
        URLQueryParser queryParser = createQueryParser(filters);
        CriteriaQuery query = queryParser.makeCriteriaCountQuery();

        return (long) entityManager.createQuery(query).getSingleResult();
    }

    public Class<T> getEntityClass() {
        return tClass;
    }

    public <T> URLQueryParser createQueryParser(String fields, String filters, String orders) {
        URLQueryParser queryParser = new URLQueryParser<T>(fields, filters, orders)
                .setEntityManager(entityManager)
                .setEntityClass(getEntityClass());

        return queryParser;
    }

    public <T> URLQueryParser createQueryParser(String filters) {
        URLQueryParser queryParser = new URLQueryParser<T>(filters)
                .setEntityManager(entityManager)
                .setEntityClass(getEntityClass());

        return queryParser;
    }

    public Sort parseSorts(String sorter){
        if (!StringUtils.isEmpty(sorter)) {
            String[] orderArray = sorter.split(",");

            List<Sort.Order> orderList = new ArrayList<>(orderArray.length);
            Arrays.stream(orderArray).forEach(
                    elem -> orderList.add(
                            elem.startsWith("+") ? new Sort.Order(Sort.Direction.ASC, elem.substring(1)):
                                    new Sort.Order(Sort.Direction.DESC, elem.substring(1))));
            return new Sort(orderList);
        }
        return null;
    }

    public JpaRepository getJpaRepository(){
        return (JpaRepository) SpringContextUtils.getService(repoClass);
    }

    public R getRepository() {
        return SpringContextUtils.getService(repoClass);
    }

    public Session currentSession() {
        return entityManager.unwrap(Session.class);
    }

    public String getEntityName(){
        return getEntityClass().getName();
    }

    public String getEntityIdFiled(){
        EntityType entityType = entityManager.getMetamodel().entity(getEntityClass());
        javax.persistence.metamodel.Type type = entityType.getIdType();
        return entityType.getId(type.getJavaType()).getName();
    }

    public String getEntityIdType(){
        EntityType entityType = entityManager.getMetamodel().entity(getEntityClass());
        javax.persistence.metamodel.Type type = entityType.getIdType();
        return type.getJavaType().getName();
    }

    /**
     * 将实体转换为模型。
     *
     * @param source
     * @param target
     * @param <T>
     * @return
     */
    public <T> T convertToModel(Object source, Class<T> target) {
        if (source == null) {
            return null;
        }
        T _target = BeanUtils.instantiate(target);
        BeanUtils.copyProperties(source, _target);
        return _target;
    }

    /**
     * 将实体集合转换为模型集合。
     * @param sources
     * @param targets
     * @param target
     * @param <T>
     * @return
     */
    public <T> List<T> convertToModels(Collection sources, List<T> targets, Class<T> target){
        if (null == sources) {
            return null;
        }
        sources.forEach(item -> {
            T _target = BeanUtils.instantiate(target);
            BeanUtils.copyProperties(item, _target);
            targets.add(_target);
        });
        return targets;
    }

    public String getCode() {
        return UUID.randomUUID().toString().replaceAll("-", "");
    }

    /**
     * 获取指定长度的随机数字字符串
     * @param length
     * @return
     */
    public String randomInt(int length) {
        String str = "0123456789";
        StringBuffer buffer = new StringBuffer();
        Random random = new Random();
        for(int i = 0; i < length; ++i) {
            int pos = random.nextInt(str.length());
            buffer.append(str.charAt(pos));
        }
        return buffer.toString();
    }

    /**
     * 获取指定长度的随机字符串
     * @param length
     * @return
     */
    public String randomString(int length) {
        String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        StringBuffer buffer = new StringBuffer();
        Random random = new Random();
        for (int i = 0; i < length; i++) {
            int pos = random.nextInt(str.length());
            buffer.append(str.charAt(pos));
        }
        return buffer.toString();
    }

    /**
     * 排序条件 第一个字符为 + 表示升序，第一个字符为 - 表示减序，不包含 + 或者 - 默认升序
     * @param sorts
     * @return
     */
    public Sort createSort(String sorts){
        Sort sort = null;
        if (!org.springframework.util.StringUtils.isEmpty(sorts)) {
            // 默认升序
            if(sorts.contains("-")){
                sort = new Sort(Sort.Direction.DESC,sorts.substring(1,sorts.length()).split(","));
            }else if(sorts.contains("+")){
                sort = new Sort(Sort.Direction.ASC,sorts.substring(1,sorts.length()).split(","));
            }else{
                sort = new Sort(Sort.Direction.ASC,sorts.split(","));
            }
        }
        return sort;
    }

    /**
     * 创建分页对象
     * @param page
     * @param size
     * @param sorts
     * @return
     */
    public Pageable createPage(Integer page, Integer size, String sorts){
        PageRequest pageRequest = null;
        if(null == page || page <= 0){
            page = defaultPage;
        }
        if(null == size || size <= 0){
            size = defaultSize;
        }
        if(!org.apache.commons.lang3.StringUtils.isEmpty(sorts)){
            pageRequest = new PageRequest(page,size,createSort(sorts));
        }else{
            pageRequest = new PageRequest(page,size);
        }

        return pageRequest;
    }
}