import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

/* Java application that reads a rectangular "map" from a file
** (whose name is specified either via a command line argument
** or, absent that, by the user in response to a prompt) and
** then has a MapRegionFinder object identify the regions within
** the map.  Both the original map and the "map of region IDs"
** are displayed.
** Input data is assumed to be in the format illustrated by this example:
** +---------+
** | 5 7     |    // # rows and columns, respectively
** | AAABBCC |    // 1st row
** | AABBBBC |    // 2nd row
** | CCCBBCC |    // etc., etc.
** | CCAAAAA |
** | AAABBBB |
** +---------+
*/

public class MapRegionFinderApp {

   public static void main(String[] args) {

      // Establish the name of the input file. 
      String inputFileName;
      if (args.length != 0) 
         { inputFileName = args[0]; }
      else 
         { inputFileName = getStringFromUser("Enter input file name: "); }

      doStuff(inputFileName);
   }

   private static void doStuff(String inputFileName) {

      char[][] theMap = readMap(inputFileName);

      // Create a MapRegionFinder object and feed the map to it.
      MapRegionFinder mrf = new MapRegionFinder(theMap);

      // Print the map and the map of computed region ID's
      System.out.println("The map:");
      mrf.printMap();
      System.out.println("\nRegion IDs:");
      mrf.printRegionIds();

      /*
      // This code segment finds the regions of the map when it is
      // interpreted in the "wraparound" fashion.
      mrf = new MapRegionFinder(theMap, true);
      System.out.println("\nRegion IDs (wraparound):");
      mrf.printRegionIds();
      */

   }


   /* Returns a new map (an array of type char[][]) corresponding to that
   ** described by the data in the file having the specified name.
   ** The data there is assumed to be in the format described in the 
   ** header comments.
   */
   private static char[][] readMap(String fileName) {
      Scanner input = null;
      try { 
         input = new Scanner(new File(fileName));
      } 
      catch (FileNotFoundException e) {
         System.out.println("Cannot find file named " + fileName);
         System.out.println("Execution is aborting.");
         System.exit(0);
      }

      int numRows = input.nextInt();
      int numCols = input.nextInt();
      input.nextLine();
      char[][] theMap = new char[numRows][numCols];
      for (int i=0; i != numRows; i++) {
         String line = input.nextLine();
         for (int j=0; j != numCols; j++) {
            theMap[i][j] = line.charAt(j);
         }
      }
      return theMap;
   }


   /* Prints the specified prompt and returns the string entered
   ** in response by the user.
   */
   private static String getStringFromUser(String prompt) {
      Scanner keyboard = new Scanner(System.in);
      System.out.print(prompt);
      String response = keyboard.nextLine().trim();
      System.out.println(response);
      return response;
   }
}