public static HashMap<Integer, String> getCoursesByDatetime() throws IOException, GeneralSecurityException {
        // Build a new authorized API client service.
        LocalDate localDate = LocalDate.now();
        LocalTime localTime = LocalTime.now().minus(Duration.ofHours(1));
        int rowIndex = 1;
        List<String> courses = new ArrayList<>();
        final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
        final String spreadsheetId = "11YgZf49a5olHPqKJTjJODlwiIIDBw9eHg98rfnqu1GE";
        final String daysRange = "A1:A800";
        Sheets service = new Sheets.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials(HTTP_TRANSPORT))
                .setApplicationName(APPLICATION_NAME)
                .build();
        ValueRange response = service.spreadsheets().values()
                .get(spreadsheetId, daysRange)
                .execute();
        List<List<Object>> values = response.getValues();
        if (values == null || values.isEmpty()) {
            System.out.println("No data found.");
        } else {
            System.out.println(localDate);
            System.out.println(values);
            for (int i = 0; i < values.size(); i++) {

                if (!values.get(i).isEmpty() && localDate.toString().equals(values.get(i).get(0).toString())) {
                    rowIndex = i + 1;
                    System.out.println(rowIndex);
                }
            }
        }

        final String timeRange = "D" + rowIndex + ":D" + (rowIndex+7);
        System.out.println(timeRange);
        response = service.spreadsheets().values()
                .get(spreadsheetId, timeRange)
                .execute();
        values = response.getValues();
        if (values == null || values.isEmpty()) {
            System.out.println("No data found.");
        } else {
            for (int i = 0; i < values.size(); i++) {
                LocalTime startTime = LocalTime.parse(values.get(i).get(0).toString().split("-")[0]);
                LocalTime endTime = LocalTime.parse(values.get(i).get(0).toString().split("-")[1]);
                if(startTime.isBefore(localTime) && endTime.isAfter(localTime)) {
                    rowIndex = rowIndex+i;
                }
            }
        }

        HashMap<Integer, String> currentCourses = new HashMap<Integer, String>();

        final String courseRange = "E" + rowIndex + ":AO" + rowIndex;
        response = service.spreadsheets().values()
                .get(spreadsheetId, courseRange)
                .execute();
        values = response.getValues();
        if (values == null || values.isEmpty()) {
            System.out.println("No data found.");
        } else {
            for (int i = 0; i < values.get(0).size(); i++) {
                if(values.get(0).get(i) != "") {
                    currentCourses.put(i+1, values.get(0).get(i).toString());
                }
            }
        }
        return currentCourses;
    }