Google Sheets – Adding Multiple Rows Using Script

You were pretty close. Here's a piece of code of which I think works:

Code

function autoAddRows() {
  var sh = SpreadsheetApp.getActiveSheet();
  var cRow = sh.getActiveRange().getRowIndex(), mRow = sh.getMaxRows();

  if((mRow-cRow) < 1) {
    var lCol = sh.getLastColumn(), key = sh.getRange(mRow,lCol).getValue();
    sh.insertRowAfter(mRow), sh.getRange(mRow+1,lCol).setValue(key+1);
  }
}

Remarks

• var ss isn't necessary, since you don't use it in the script.
• you need the row of the active cell, compared to the last row (getMaxRows)
• add all the goodies into the IF statement that need to be executed, when mRow-cRow=0

Example

I've prepared a file for you to experiment with: Inserting Rows + Reference

Try this code:

function AddRow() {
  //gets the spreadsheet which it's bound to
  var ssheet = SpreadsheetApp.getActiveSpreadsheet();  

  //gets all sheets in this spreadsheet
  var sheet = ssheet.getSheets();                      

  //browses all the sheets, until "i" is larger than the number of sheets
  for (var i = 0; i < sheet.length; i++)               
  {
    //adds to the actual sheet a row AFTER the first row
    sheet[i].insertRowAfter(1);                        
  }
}

and trigger it on a daily basis (like on 1 a.m.)