// Written by Amit Agarwal www.ctrlq.org
// Email: amit@labnol.org

function convertDocuments() {
  // Convert xlsx file to Google Spreadsheet
  convertToGoogleDocs_('Excel File.xlsx');

  // Convert .doc/.docx files to Google Document
  convertToGoogleDocs_('Microsoft Word Document.doc');

  // Convert pptx to Google Slides
  convertToGoogleDocs_('PowerPoint Presentation.pptx');
}

// By Google Docs, we mean the native Google Docs format
function convertToGoogleDocs_(fileName) {
  var officeFile = DriveApp.getFilesByName(fileName).next();

  // Use the Advanced Drive API to upload the Excel file to Drive
  // convert = true will convert the file to the corresponding Google Docs format

  var uploadFile = JSON.parse(
    UrlFetchApp.fetch('https://www.googleapis.com/upload/drive/v2/files?uploadType=media&convert=true', {
      method: 'POST',
      contentType: officeFile.getMimeType(),
      payload: officeFile.getBlob().getBytes(),
      headers: {
        Authorization: 'Bearer ' + ScriptApp.getOAuthToken(),
      },
      muteHttpExceptions: true,
    }).getContentText()
  );

  // Remove the file extension from the original file name
  var googleFileName = officeFile.substr(0, officeFile.lastIndexOf('.'));

  // Update the name of the Google Sheet created from the Excel sheet
  DriveApp.getFileById(uploadFile.id).setName(googleFileName);

  Logger.log(uploadFile.alternateLink);
}