I want copy current sheet to new one and sheet name change.

var ss = SpreadsheetApp.getActiveSpreadsheet();
var sourceSheet = ss.getSheetByName('sheet_name');  <=== question 1
var copy = sourceSheet.copyTo(ss);
ss.setActiveSheet(copy);// set it active
ss.moveActiveSheet(ss.getNumSheets());// move it to the last position 
copy.setName(' newSheetName is add 1 from current sheet name'); <== question 2

question 1:
I need current sheet name or ID.

question 2:
if current sheet name is '10', add 1 for new Sheet name
I don't know how to add string type of sheet name.