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

public class MazeTester
{
    protected Maze maze;

    protected BackTrack backTrack;

    protected Position start,
                       finish;

    /**
     * Reads in the maze information.
     */    
    public void readMaze()
    {
        final String PROMPT =
            "\n\nPlease enter the path for the file whose first line contains the " +
            "number of rows and columns,\nwhose 2nd line the start row and column, " +
            "whose 3rd line the finish row and column, and then the maze, row-by-row: ";

        BufferedReader keyboardReader = new BufferedReader (
                                           new InputStreamReader (System.in));

        String fileName;

        BufferedReader fileReader;

        byte[ ][ ] grid = null;

        boolean fileFound = false;

        while (!fileFound)
        {
            try
            {
	     	System.out.print (PROMPT);  
                fileName = keyboardReader.readLine();
                fileReader = new BufferedReader (new FileReader (fileName));
                fileFound = true;

                StringTokenizer tokens;

                tokens = new StringTokenizer (fileReader.readLine());
                int rows = Integer.parseInt (tokens.nextToken()),
                columns = Integer.parseInt (tokens.nextToken());

                grid = new byte [rows][columns];

                tokens = new StringTokenizer (fileReader.readLine());
                start = new Position (Integer.parseInt (tokens.nextToken()),
                                      Integer.parseInt (tokens.nextToken()));

                tokens = new StringTokenizer (fileReader.readLine());
                finish = new Position (Integer.parseInt (tokens.nextToken()),
                                       Integer.parseInt (tokens.nextToken()));

                for (int i = 0; i < rows; i++)
                {
                    tokens = new StringTokenizer (fileReader.readLine());
                    for (int j = 0; j < columns; j++)
                        grid [i][j] = (byte)Integer.parseInt (tokens.nextToken());
                } // reading in maze entries
	        fileReader.close();
            } // try
            catch (IOException e)
            {
                System.out.print (e);
            } // catch IOException
        } // while
        maze = new Maze (grid, finish);
        backTrack = new BackTrack (maze);
    } // method readMaze


    /**
     * Prints the results of the maze search.
     */
    public void printResults()
    {
        final String INITIAL_STATE =
            "\nThe initial state is as follows (0 = WALL, 1 = CORRIDOR):\n";

        final String START_INVALID = "The start position is invalid.";

        final String FINISH_INVALID = "The finish position is invalid.";

        final String FINAL_STATE =
            "The final state is as follows (2 = DEAD END, 9 = PATH):\n";

        final String SUCCESS =
            "\n\nA solution has been found:";

        final String FAILURE =
            "\n\nThere is no solution:";

        System.out.println (INITIAL_STATE + maze);
        if (!maze.isOK (start))
            System.out.println (START_INVALID);
        else if (!maze.isOK (finish))
            System.out.println (FINISH_INVALID);
        else
        {
            maze.markAsPossible (start);
            if (maze.isGoal (start) || backTrack.tryToReachGoal (start))
                System.out.println (SUCCESS);
            else
            {
                maze.markAsDeadEnd (start);
                System.out.println (FAILURE);
            } // failure
            System.out.println (FINAL_STATE + maze);
        } // start and finish are valid
    } // method printResults

} // class MazeTester