import java.util.Scanner;

public class World
{
    // World is a 2D array.
    // Each element is a reference to a Tardis object
    // All elements but one will be null
    // One element will refer to a Tardis object (the Doctor's tardis).
    private Tardis [][] grid;

    // These two values determine the size of the world
    private int maxRow;
    private int maxColumn;

    // Current location of the Doctor's tardis
    private Location tardisLocation;

    public World()
    {
        final int START_ROW = 0;
        final int START_COLUMN = 0;
        Scanner in = new Scanner(System.in);
        System.out.println("Creating the game world");
        System.out.print("Max rows: ");
        maxRow = in.nextInt();
        System.out.print("Max columns: ");
        maxColumn = in.nextInt();
        grid = new Tardis[maxRow][maxColumn];
        wipe();   // Empties the world
        grid[START_ROW][START_COLUMN] = new Tardis(10);   // Put the Doctor's Tardis here.
        tardisLocation = new Location(START_ROW,START_COLUMN);
        display();
    }

    public void display()
    {
        int r;
        int c;
        for (r = 0; r < maxRow; r++)
        {
            for (c = 0; c < maxColumn; c++)
            {
                if (grid[r][c] == null)
                    System.out.print(".");
                else
                    System.out.print("T");
            }
            System.out.println();
        }
    }

    /*
      Queries the element referring to the Tardis object to determine if it has energy remaining.
    */
    public boolean energyRemains()
    {
        boolean isThereEnergy;
        isThereEnergy = grid[tardisLocation.getRow()][tardisLocation.getColumn()].hasEnergy();
        return(isThereEnergy);
    }

    public void move()
    {
        // Get the current Row/Col coordinates of the Tardis
        int currentRow = tardisLocation.getRow();
	int currentColumn = tardisLocation.getColumn();
        int oldRow = currentRow;
        int oldColumn = currentColumn;

        System.out.println("Tardis dematerializing");
        tardisLocation = grid[currentRow][currentColumn].calculateCoordinates(maxRow,maxColumn);

        // Update temporary values with current location
        currentRow = tardisLocation.getRow();
        currentColumn = tardisLocation.getColumn();

        // Copy the reference to the tardis from the old location to the new one.
        grid[currentRow][currentColumn] = grid[oldRow][oldColumn];

	
        // Check if tardis trying to move onto same square, don't 'wipe' if this is the case or
        // tardis will be lost in the temporal void!
        if ((currentRow == oldRow) && (currentColumn == oldColumn))
        {
            System.out.println("Rematerializing in same location");
        }
        else
        {
            // old location no longer refers to the tardis because the tardis has 'moved' off of it.
            grid[oldRow][oldColumn] = null;
        }
        System.out.println("Tardis re-materializing");
        display();
    }

    public void wipe()
    {
        int r;
        int c;
        for (r = 0; r < maxRow; r++)
        {
            for (c = 0; c < maxColumn; c++)
            {
                grid[r][c] = null;
            }    
        }
    }
}