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package com.github.aidensuen.mongo.pagehelper;

import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;

import java.io.Closeable;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * thanks https://github.com/pagehelper/
 */
public class Page extends PageRequest implements Closeable {

    private static final long serialVersionUID = -1376111841926300921L;


    /**
     * default sort field
     */
    private String ID_NAME = "_id";

    /**
     * it will skip(0) when this sort field is not null and use ID_NAME to sort
     */
    private Object lastId;

    /**
     * first line
     */
    private long startRow;

    /**
     * last line
     */
    private long endRow;

    /**
     * whether count
     */
    private boolean count = true;

    /**
     * total
     */
    private long total;

    /**
     * total pages
     */
    private int pages;

    private List result;

    private Page(int pageNum, int pageSize, Sort sort) {
        super(pageNum, pageSize, sort);
        result = new ArrayList<>(0);
    }

    public static Page of(int[] offset, boolean count) {
        return of(offset, count, Sort.unsorted());
    }

    public static Page of(int[] offset, boolean count, Sort sort) {
        int pageNum = 0;
        int pageSize;
        if (offset[0] == 0 && offset[1] == Integer.MAX_VALUE) {
            pageSize = 1;
        } else {
            pageSize = offset[1];
            pageNum = offset[1] != 0 ? (int) (Math.ceil(((double) offset[0] + offset[1]) / offset[1]) - 1) : 0;
        }
        Page page = of(pageNum, pageSize, count, sort);
        return page;
    }

    public static Page of(int pageNum, int pageSize) {
        return of(pageNum, pageSize, true, Sort.unsorted());
    }

    public static Page of(int pageNum, int pageSize, boolean count) {
        return of(pageNum, pageSize, count, Sort.unsorted());
    }

    public static Page of(int pageNum, int pageSize, Sort sort) {
        return of(pageNum, pageSize, true, sort);
    }

    public static Page of(int pageNum, int pageSize, Object lastId) {
        return of(pageNum, pageSize, true, lastId);
    }

    public static Page of(int pageNum, int pageSize, boolean count, Object lastId) {
        Page page = of(pageNum, pageSize, count, Sort.unsorted());
        page.setLastId(lastId);
        return page;
    }

    public static Page of(int pageNum, int pageSize, boolean count, Sort sort) {
        if (pageNum == 0 && pageSize == Integer.MAX_VALUE) {
            pageSize = 1;
        }
        Page page = new Page(pageNum, pageSize, sort);
        page.setCount(count);
        page.calculateStartAndEndRow();
        return page;
    }

    private Page calculateStartAndEndRow() {
        this.startRow = this.getOffset();
        this.endRow = this.startRow + this.getPageSize();
        return this;
    }

    public String getID_NAME() {
        return ID_NAME;
    }

    public Page setID_NAME(String ID_NAME) {
        this.ID_NAME = ID_NAME;
        return this;
    }

    public Object getLastId() {
        return lastId;
    }

    public Page setLastId(Object lastId) {
        this.lastId = lastId;
        return this;
    }

    public List getResult() {
        return result;
    }

    public Page setResult(List result) {
        this.result = result;
        return this;
    }

    public boolean isCount() {
        return count;
    }

    public Page setCount(boolean count) {
        this.count = count;
        return this;
    }

    public long getStartRow() {
        return startRow;
    }

    public Page setStartRow(long startRow) {
        this.startRow = startRow;
        return this;
    }

    public long getEndRow() {
        return endRow;
    }

    public Page setEndRow(long endRow) {
        this.endRow = endRow;
        return this;
    }

    public long getTotal() {
        return total;
    }

    public Page setTotal(long total) {
        this.total = total;
        if (total == -1) {
            pages = 1;
            return this;
        }
        if (getPageSize() > 0) {
            pages = (int) (total / getPageSize() + ((total % getPageSize() == 0) ? 0 : 1));
        } else {
            pages = 0;
        }
        if (getPageNumber() > pages) {
            if (pages != 0) {
                Page page = of(pages, getPageSize(), isCount(), getSort());
                page.setPages(pages).setTotal(total).setID_NAME(getID_NAME()).setLastId(getLastId()).setResult(getResult()).calculateStartAndEndRow();
                return page;
            }
            return this;
        } else {
            return this;
        }
    }

    public int getPages() {
        return pages;
    }

    public Page setPages(int pages) {
        this.pages = pages;
        return this;
    }

    public PageInfo toPageInfo() {
        PageInfo pageInfo = new PageInfo(this.getResult(), this, getTotal());
        return pageInfo;
    }

    @Override
    public void close() {
        PageHelper.clearPage();
    }
}