DiaTrack

import java.io.*;
import java.util.*;
import java.text.*;

public class DiaTrackApp
{
    public final static String VALIDHEADER = "Date,Time,BloodSugar,Humalog,Lantis,Carbs";
    public final static String COMMA = ",";
    public final static String NEWLINE = System.lineSeparator();
    public final static String DEFAULTPATH = "C:\\Users\\DigiDuncan\\Desktop\\DiaTrack";
    public static String fileName = DEFAULTPATH + "\\diatrack.csv";
    public static File spreadsheet = new File (fileName);
    public static String dateString = "1970-1-1";
    public static String timeString = "00:00";
    public static String entry = null;
    public static String entryDate, entryTime;
    public static int entryBloodSugar, entryHumalog, entryLantis, entryCarbs;
    public static Scanner input = new Scanner(System.in);

    public static void main(String[] args) throws IOException
    {
        String choice = "n";

        final String GUI =  "\n+-[DIATRACK]--------------+" +
                            "\n|                         |" +
                            "\n| (M) Manual Entry        |" +
                            "\n| (A) Assisted Entry      |" +
                            "\n| (F) Fresh Start         |" +
                            "\n| (X) Exit                |" +
                            "\n|                         |" +
                            "\n+-------------------------+\n";

        getCurrentDateTime();
        System.out.println("Debug: " + isValidFile(fileName));
        System.out.println(GUI);

        System.out.print(">");
        choice = input.nextLine();

        switch (choice)
        {
            case "m":
                manualEntry();
                break;
            case "a":
                assistedEntry();
                break;
            case "f":
                freshStart();
                break;
            case "x":
                System.exit(0);
                break;
            default:
                System.err.println("Unrecognized menu option! (Error code UMO)");
        }
    }

    public static void getCurrentDateTime()
    {
        // Get today's date.
        Date today = Calendar.getInstance().getTime();

        // (2) create a date and a time formatter.
        SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat timeFormatter = new SimpleDateFormat("HH:mm");

        //Set the global variables correctly.
        dateString = dateFormatter.format(today);
        timeString = timeFormatter.format(today);

        System.out.println("Debug: " + dateString + " " + timeString);
    }

    public static boolean isValidFile (String file)
    {
        try
        {
            FileReader fileReader = new FileReader(file);

            // Always wrap FileReader in BufferedReader.
            BufferedReader bufferedReader = new BufferedReader(fileReader);

            String header = bufferedReader.readLine();

            // Always close files.
            bufferedReader.close();

            System.out.println("Debug: " + header);

            return header.equals(VALIDHEADER);
        }
        catch(FileNotFoundException ex)
        {
            System.err.println(
                "Unable to open file '" + file + "' (Error code UOF)");
            return false;
        }
        catch(IOException ex)
        {
            System.err.println(
                "Error reading file '" + file + "' (Error code ERF)");
            return false;
        }
    }

    public static void freshStart() throws IOException
    {
        FileWriter spreadsheetWriter = new FileWriter(spreadsheet);

        if (spreadsheet.exists())
        {
            spreadsheet.delete();
            spreadsheet.createNewFile();
            spreadsheetWriter.write(VALIDHEADER + NEWLINE);
        }
        else
        {
            spreadsheet.createNewFile();
            spreadsheetWriter.write(VALIDHEADER + NEWLINE);
        }

        spreadsheetWriter.close();

        System.out.println("Fresh Start successful! File located at " + fileName);
    }

    public static void manualEntry() throws IOException
    {
        FileWriter spreadsheetWriter = new FileWriter(spreadsheet, true);

        System.out.println("Input date (yyyy-MM-dd):");

        System.out.print(">");
        entryDate = input.nextLine();

        System.out.println("Input time (HH:mm, 24hr time):");

        System.out.print(">");
        entryTime = input.nextLine();

        System.out.println("Input blood sugar (mg/dL):");

        System.out.print(">");
        entryBloodSugar = input.nextInt();

        System.out.println("Input Humalog (cc):");

        System.out.print(">");
        entryHumalog = input.nextInt();

        System.out.println("Input Lantis (cc):");

        System.out.print(">");
        entryLantis = input.nextInt();

        System.out.println("Input carbohydate intake (g):");

        System.out.print(">");
        entryCarbs = input.nextInt();

        entry = entryDate + COMMA + entryTime + COMMA + entryBloodSugar + COMMA +
                entryHumalog + COMMA + entryLantis + COMMA + entryCarbs + NEWLINE;

        spreadsheetWriter.write(entry);

        spreadsheetWriter.close();

        System.out.println("Successfully wrote " + entry + " to " + fileName);
    }
    public static void assistedEntry() throws IOException
    {
        FileWriter spreadsheetWriter = new FileWriter(spreadsheet, true);

        entryDate = dateString;
        entryTime = timeString;

        System.out.println("Input blood sugar (mg/dL):");

        System.out.print(">");
        entryBloodSugar = input.nextInt();

        System.out.println("Input Humalog (cc):");

        System.out.print(">");
        entryHumalog = input.nextInt();

        System.out.println("Input Lantis (cc):");

        System.out.print(">");
        entryLantis = input.nextInt();

        System.out.println("Input carbohydate intake (g):");

        System.out.print(">");
        entryCarbs = input.nextInt();

        entry = entryDate + COMMA + entryTime + COMMA + entryBloodSugar + COMMA +
                entryHumalog + COMMA + entryLantis + COMMA + entryCarbs + NEWLINE;

        spreadsheetWriter.write(entry);

        spreadsheetWriter.close();

        System.out.println("Successfully wrote " + entry + " to " + fileName);
    }
}