package com.edu.base;

/**
 * @author wu youyang
 */

import com.alibaba.fastjson.JSON;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;

import java.io.Serializable;

@ApiModel(description = "分页对象")
public class Page implements Serializable {
	private static final long serialVersionUID = -4312323165564562319L;

	@ApiModelProperty("页码")
	private int page = 1;

	@ApiModelProperty("每页条数")
	private int pageSize = 10;
	
	/**
	 * 总记录数, -1: 未知
	 */
	private int total = -1;

	public int getPage() {
		return page;
	}

	/**
	 * 当前页码, 1-based
	 */
	public void setPage(int page) {
		this.page = page;
	}

	/**
	 * 每页记录数
	 */
	public int getPageSize() {
		return pageSize;
	}

	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}

	public int getTotal() {
		return total;
	}

	public void setTotal(int total) {
		this.total = total;
	}

	public int getPrevPage() {
		return this.isFirstPage() ? this.getPage() : this.getPage() - 1;
	}

	public int getNextPage() {
		return this.isLastPage() ? this.getPage() : this.getPage() + 1;
	}

	public boolean isFirstPage() {
		return (1 == this.getPage());
	}

	public boolean isLastPage() {
		if(-1 == this.getPageCount()){
			return false;
		}
		
		return (this.getPageCount() < 1 || this.getPageCount() <= this.getPage());
	}

	/**
	 * 页数, 根据total和pageSize计算
	 * -1: 未知
	 * @return 
	 */
	public int getPageCount() {
		if(-1 == total){
			return -1;
		}
		
		if (total < 1) {
			return 0;
		}
		
		if (pageSize < 1) {
			return 1;
		}

		return (0 == total % pageSize) ? total / pageSize : total / pageSize
				+ 1;
	}

	/**
	 * 
	 * mysql offset, 0-based, 根据page和pageSize计算
	 * 
	 * @return
	 */
	public int getOffset() {
		if (page < 1) {
			return 0;
		}

		return (page - 1) * pageSize;
	}

	/**
	 * mysql limit, 0-based, 根据page和pageSize计算
	 * 
	 * @return
	 */
	public int getLimit() {
		return pageSize;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + page;
		result = prime * result + pageSize;
		result = prime * result + total;

		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj){
			return true;
		}
		if (obj == null){
			return false;
		}
		if (getClass() != obj.getClass()){
			return false;
		}
		Page other = (Page) obj;
		if (page != other.page){
			return false;
		}
		if (pageSize != other.pageSize){
			return false;
		}
		if (total != other.total){
			return false;
		}
		
		return true;
	}

	public String toString() {
		return JSON.toJSONString(this);
	}
}