package com.ruoyi.interchange.util;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class MongoDBPageUtils {
    @Autowired
    private static MongoTemplate mongoTemplate;

    @Autowired
    public void setMongoTemplate(MongoTemplate mongoTemplate) {
        MongoDBPageUtils.mongoTemplate = mongoTemplate;
    }

    /**
     * MongDb分页公共方法
     *
     * @param clazz    实体类的class对象
     * @param pageSize 每页的数量
     * @param pageNum  当前的页数
     * @param query    query是啥不知道赶紧去查下，相当于sql语句
     * @return
     */
    public static <T> PageResult<T> pagination(Class<T> clazz, int pageNum, int pageSize, Query query) {
        long total = mongoTemplate.count(query, clazz);
        Integer pages = (int) Math.ceil((double) total / (double) pageSize);
        if (pageNum <= 0 || pageNum > pages) {
            pageNum = 1;
        }
        int skip = pageSize * (pageNum - 1);
        query.skip(skip).limit(pageSize);
        List<T> list = mongoTemplate.find(query, clazz);
        PageResult pageResult = new PageResult();
        pageResult.setTotal(total);
        pageResult.setPages(pages);
        pageResult.setPageSize(pageSize);
        pageResult.setPageNum(pageNum);
        pageResult.setList(list);
        return pageResult;
    }
}