Looping through selected cells to indent text - google-apps-script

Question

I have written the following Google Spreadsheet script that attempts to loop through all selected cells and then update the value so that it adds an indent, by adding =CONCAT(REPT( CHAR( 160 ), 5),"' + value[row] + '") around the value.
However I am hitting an error when processing the loop and I am unsure how the code should be modified to correct/resolve. The error I am getting is: TypeError: Cannot call method "setValue" of undefined.
Does anyone know what I should change?
var ss = SpreadsheetApp.getActiveSpreadsheet();
function indentText() {
var cells = ss.getActiveRange();
var values = cells.getValues();
row = [];
len = [];
Logger.log(values);
for (row = 0, len = values.length; row < len; row++) {
if (values[row] != '') {
cells[row].setValue('=CONCAT(REPT( CHAR( 160 ), 5),"' + value[row] + '")');
}
}
};
function onOpen() {
var sheet = SpreadsheetApp.getActiveSpreadsheet();
var entries = [{
name : "Indent Text",
functionName : "indentText"
}];
sheet.addMenu("Indent Text", entries);
};
Edit: After reviewing my code I now have a working solution. I have added it here for completeness:
var ss = SpreadsheetApp.getActiveSpreadsheet();
function indentText() {
var values = ss.getActiveRange().getValues();
var newValues = new Array();
for (i = 0; i < values.length; i++) {
if (values[i][0] != '') {
newValues.push(['=CONCAT(REPT( CHAR( 160 ), 5),"' + values[i][0] + '")']);
} else {
newValues.push(['']);
}
}
ss.getActiveRange().setValues(newValues);
};
function onOpen() {
var sheet = SpreadsheetApp.getActiveSpreadsheet();
var entries = [{
name : "Indent Text",
functionName : "indentText"
}];
sheet.addMenu("Indent Text", entries);
};
Of course would be interested if there is a better way to achieve this.