const REQUESTS_SHEET = 'Requests';
const STATUS_COLUMN = 3;

/**
 * Returns the bound spreadsheet's Requests sheet or stops with a clear error.
 *
 * @returns {SpreadsheetApp.Sheet}
 */
function getRequestsSheet_() {
  const sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(REQUESTS_SHEET);
  if (sheet === null) {
    throw new Error('Add a sheet tab named ' + REQUESTS_SHEET + ' before running this function.');
  }
  return sheet;
}

/**
 * Reads the request rows below the header. Returns an empty array when the
 * sheet has only a header row.
 *
 * @param {SpreadsheetApp.Sheet} sheet
 * @returns {unknown[][]}
 */
function readRequestRows_(sheet) {
  const lastRow = sheet.getLastRow();
  if (lastRow < 2) {
    return [];
  }
  return sheet.getRange(2, 1, lastRow - 1, STATUS_COLUMN).getValues();
}

/**
 * Logs the title of every request row.
 *
 * @returns {void}
 */
function logRequestTitles() {
  const rows = readRequestRows_(getRequestsSheet_());
  rows.forEach(function (row) {
    Logger.log(row[1]);
  });
}

/**
 * Logs how many requests are not Done.
 *
 * This function contains three mistakes. Open it in the Apps Script editor
 * with myFunction installed, then fix each one by reading the Problems panel.
 *
 * @returns {void}
 */
function countOpenRequests() {
  const sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(REQUESTS_SHEET);
  const lastRow = sheet.getLastRow();
  const rows = sheet.getRange(2, 1, lastRow - 1, '3').getValues();
  const open = rows.filter(function (row) {
    return row[STATUS_COLUMN - 1] !== 'Done';
  });
  Logger.log('Open requests: ' + open.lenght);
}