import lombok.Data;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

@Data
public class PageUtils implements Serializable {
    private static final long serialVersionUID = 1L;
    /**
     * 总记录数
     */
    private int totalCount;
    /**
     * 每页记录数
     */
    private int pageSize;
    /**
     * 总页数
     */
    private int totalPage;
    /**
     * 当前页数
     */
    private int currPage;
    /**
     * 列表数据
     */
    private List<?> list;

    /**
     * 分页
     * @param list        列表数据
     * @param totalCount  总记录数
     * @param pageSize    每页记录数
     * @param currPage    当前页数
     */
    public PageUtils(List<?> list, int totalCount, int pageSize, int currPage) {
        this.list = list;
        this.totalCount = totalCount;
        this.pageSize = pageSize;
        this.currPage = currPage;
        this.totalPage = (int)Math.ceil((double)totalCount/pageSize);
    }

    // 列表直接分页
    public  static  List<Map<String, Object>> pageBySubList(List list, int pagesize, int currentPage) {
        int totalcount = list.size();
        int pagecount = 0;
        List<Map<String, Object>>  subList=new ArrayList<>();
        int m = totalcount % pagesize;
        if (m > 0) {
            pagecount = totalcount / pagesize + 1;
        } else {
            pagecount = totalcount / pagesize;
        }
        if(((currentPage - 1) * pagesize )>=totalcount){
            return subList;
        }
        if (m == 0) {
            subList = list.subList((currentPage - 1) * pagesize, pagesize * (currentPage) > totalcount ? totalcount-1 : pagesize * (currentPage));
        } else {
            if (currentPage == pagecount) {
                subList = list.subList((currentPage - 1) * pagesize, totalcount);
            } else {
                subList = list.subList((currentPage - 1) * pagesize, pagesize * (currentPage) > totalcount ? totalcount-1 : pagesize * (currentPage));
            }
        }
        return subList;
    }

}