/* Java application that prompts the user to enter a string intended to 
** represent a calendar date.  This input is then passed to six methods
** in the DateConverters class, each of which attempts to recognize that 
** string as being a calendar date in one of these formats:
**
**   Format           Example
**   ---------------  ---------------
**   mm/dd/yyyy       10/08/2019
**   dd-mm-yyyy       08-10-2019
**   yyyy-mm-dd       2019-10-08
**   dd-Mon-yyyy      08-Oct-2019
**   Month day, year  October 08, 2019
**   day Month year   08 October 2019
**
** Each method attempts to convert the given string into the corresponding
** date in the yyyymmdd format (e.g., "20191008"), and the results are 
** printed for the user to see.
**
** This process repeats as long as the user enters a non-empty string, 
** at which point the program ends.
**
** Author: P.M. Jackowitz & R. McCloskey
** Date: October 2019
*/
import java.util.Scanner;

public class DateConversionDriver {

   // Global constants
   public static final char QUOTES = '"';
   public static final char SLASH = '/';
   public static final char BLANK = ' ';
   
   // Scanner object through which input data is read from the keyboard.
   public static Scanner keyboard = new Scanner(System.in);
   
   public static void main(String[] args) {
      String givenDate;
      do {
         // Prompt user to enter a calendar date value.
         System.out.print("\nEnter a calendar date:>");
         givenDate = keyboard.nextLine().trim();
         // Check for loop terminating condition
         if(givenDate.length() > 0) {
            doConversions(givenDate);
         }
      } while (givenDate.length() > 0);
      System.out.println("Done!");
   }


   /* Applies each of the conversion methods in the DateConverters class
   ** to the given string, reporting each result.  (If a conversion method
   ** throws an exception, the reported result is the empty string.)
   */
   private static void doConversions(String date) {

      final String EXCEP_MESS = "Exception!!!";

      // Convert assuming givenDate is in the mm/dd/yyyy form
      System.out.print(Pad.padRight("mm/dd/yyyy",16,BLANK));
      try {
         String yyyymmddDate = DateConverters.convertMMDDYYYY(date);
         System.out.println(quoted(yyyymmddDate));
      }
      catch (Exception e) { 
         //yyyymmddDate = "";
         System.out.println(EXCEP_MESS);
      }

      // Convert assuming date is in the dd-mm-yyyy form
      System.out.print(Pad.padRight("dd-mm-yyyy",16,BLANK));
      try {
         String yyyymmddDate = DateConverters.convertDDMMYYYY(date);
         System.out.println(quoted(yyyymmddDate));
      }
      catch (Exception e) {
         //yyyymmddDate = "";
         System.out.println(EXCEP_MESS);
      }

      // Convert assuming date is in the yyyy-mm-dd form
      System.out.print(Pad.padRight("yyyy-mm-dd",16,BLANK));
      try {
         String yyyymmddDate = DateConverters.convertYYYYMMDD(date);
         System.out.println(quoted(yyyymmddDate));
      }
      catch (Exception e) {
         //yyyymmddDate = "";
         System.out.println(EXCEP_MESS);
      }
    
      // Convert assuming date is in the dd-Mon-yyyy form
      System.out.print(Pad.padRight("dd-Mon-yyyy",16,BLANK));
      try {
         String yyyymmddDate = DateConverters.convertDDMonYYYY(date);
         System.out.println(quoted(yyyymmddDate));
      }
      catch (Exception e) {
         //yyyymmddDate = "";
         System.out.println(EXCEP_MESS);
      }

      // Convert assuming date is in the "Month day, year" form
      System.out.print(Pad.padRight("Month day, year",16,BLANK));
      try {
         String yyyymmddDate = DateConverters.convertMonthDayYear(date);
         System.out.println(quoted(yyyymmddDate));
      }
      catch (Exception e) {
         //yyyymmddDate = "";
         System.out.println(EXCEP_MESS);
      }

      // Convert assuming givenDate is in the "day Month year" form
      System.out.print(Pad.padRight("day Month year",16,BLANK));
      try {
         String yyyymmddDate = DateConverters.convertDayMonthYear(date);
         System.out.println(quoted(yyyymmddDate));
      }
      catch (Exception e) {
         //yyyymmddDate = "";
         System.out.println(EXCEP_MESS);
      }
   }
   

   // utility method
   // --------------
   
   /* Functional method that merely returns the given string surrounded 
   ** by quotes.
   */
   public static String quoted(String s) {
      return QUOTES + s + QUOTES;
   }

}