Error with indices of sheets

[FoGezz]

Hello. I create file with xlsxwriter and then read it with https://github.com/nuovo/spreadsheet-reader. I have encountered a problem that when i start reading file (it has 2 sheets) the default is the second. But it worked well when i changed $i+2 to $i+1 at the line below $workbook_xml.='<sheet name="'.self::xmlspecialchars($sheet->sheetname).'" sheetId="'.($i+1).'" state="visible" r:id="rId'.($i+2).'"/>';

xlsxwriter.class.php -> buildWorkBookXML(); What's purpose of using r:id="rId'.($i+2)? Is it correct? I couldnt find any information about that in OpenXML docs. And I cant override that implementation because of using self:: when calling

UPD: here is working code at the last version (i did it like to Excel app saves)

	{
		$i=0;
		$workbook_xml="";
		$workbook_xml.='<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'."\n";
		$workbook_xml.='<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">';
		$workbook_xml.='<fileVersion appName="Calc"/><workbookPr backupFile="false" showObjects="all" date1904="false"/><workbookProtection/>';
		$workbook_xml.='<bookViews><workbookView activeTab="0" firstSheet="0" showHorizontalScroll="true" showSheetTabs="true" showVerticalScroll="true" tabRatio="212" windowHeight="8192" windowWidth="16384" xWindow="0" yWindow="0"/></bookViews>';
		$workbook_xml.='<sheets>';
		foreach($this->sheets as $sheet_name=>$sheet) {
			$sheetname = self::sanitize_sheetname($sheet->sheetname);
			$workbook_xml.='<sheet name="'.self::xmlspecialchars($sheetname).'" sheetId="'.($i+1).'" state="visible" r:id="rId'.($i+1).'"/>';
			$i++;
		}
		$workbook_xml.='</sheets>';
		$workbook_xml.='<definedNames>';
		foreach($this->sheets as $sheet_name=>$sheet) {
			if ($sheet->auto_filter) {
				$sheetname = self::sanitize_sheetname($sheet->sheetname);
				$workbook_xml.='<definedName name="_xlnm._FilterDatabase" localSheetId="0" hidden="1">\''.self::xmlspecialchars($sheetname).'\'!$A$1:' . self::xlsCell($sheet->row_count - 1, count($sheet->columns) - 1, true) . '</definedName>';
				$i++;	
			}
		}
		$workbook_xml.='</definedNames>';
		$workbook_xml.='<calcPr iterateCount="100" refMode="A1" iterate="false" iterateDelta="0.001"/></workbook>';
		return $workbook_xml;
	}
	protected function buildWorkbookRelsXML()
	{
		$i=0;
		$wkbkrels_xml="";
		$wkbkrels_xml.='<?xml version="1.0" encoding="UTF-8"?>'."\n";
		$wkbkrels_xml.='<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">';
		foreach($this->sheets as $sheet_name=>$sheet) {
			$wkbkrels_xml.='<Relationship Id="rId'.($i+1).'" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/'.($sheet->xmlname).'"/>';
			$i++;
		}
        $wkbkrels_xml.='<Relationship Id="rId'.($i+1).'" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" Target="styles.xml"/>';
        $wkbkrels_xml.="\n";
		$wkbkrels_xml.='</Relationships>';
		return $wkbkrels_xml;
	}```