--- Game --- --- --- --- --- --- --- --- --- --- ---
import java.util.Scanner;

public class Game {

    //
    // Public
    //

    // Globals
    public static final boolean DEBUGGING  = false; // Debugging flag.
    public static final int MAX_LOCALES = 2;    // Total number of rooms/locations we have in the game.
    public static int currentLocale = 0;        // Player starts in locale 0.
    public static String command;               // What the player types as he or she plays the game.
    public static boolean stillPlaying = true; // Controls the game loop.
    public static Locale[] locations;           // An uninitialized array of type Locale. See init() for initialization.
    public static int[][]  nav;                 // An uninitialized array of type int int.
    public static int moves = 0;                // Counter of the player's moves.
    public static int score = 0;                // Tracker of the player's score.

    public static void main(String[] args) {
        if (DEBUGGING) {
            // Display the command line args.
            System.out.println("Starting with args:");
            for (int i = 0; i < args.length; i++) {
                System.out.println(i + ":" + args[i]);
            }
        }

        // Set starting locale, if it was provided as a command line parameter.
        if (args.length > 0) {
            try {
                int startLocation = Integer.parseInt(args[0]);
                // Check that the passed-in value for startLocation is within the range of actual locations.
                if ( startLocation >= 0 && startLocation <= MAX_LOCALES) {
                    currentLocale = startLocation;
                } else {
                    System.out.println("WARNING: passed-in starting location (" + args[0] + ") is out of range.");
                }
            } catch(NumberFormatException ex) {
                System.out.println("WARNING: Invalid command line arg: " + args[0]);
                if (DEBUGGING) {
                    System.out.println(ex.toString());
                }
            }
        }

        // Get the game started.
        init();
        updateDisplay();

        // Game Loop
        while (stillPlaying) {
            getCommand();
            navigate();
            updateDisplay();
        }

        // We're done. Thank the player and exit.
        System.out.println("Thank you for playing.");
    }

    //
    // Private
    //

    private static void init() {
        // Initialize any uninitialized globals.
        command = new String();
        stillPlaying = true;   // TODO: Do we need this?

        // Set up the location instances of the Locale class.
        Locale loc0 = new Locale(0);
        loc0.setName("The Lab");
        loc0.setDesc("You are in a shiny new lab.");

        Locale loc1 = new Locale(1);
        loc1.setName("Dungeon");
        loc1.setDesc("This is a dark and smelly place.");

        Space loc2 = new Space(2);
        loc2.setName("TARDIS");
        loc2.setDesc("It seems larger on the inside.");
        loc2.setNearestPlanet("Altair 6");

        // Set up the location array.
        locations = new Locale[3];
        locations[2] = loc2; // "TARDIS";   //  ^
        locations[0] = loc0; // "The Lab";  //  N
        locations[1] = loc1; // "Dungeon";  //  |

        if (DEBUGGING) {
            System.out.println("All game locations:");
            for (int i = 0; i < locations.length; ++i) {
                System.out.println(i + ":" + locations[i].toString());
            }
        }
        // Set up the navigation matrix.
        nav = new int[][] {
                                 /* N   S   E   W */
                                 /* 0   1   2   3 */
         /* nav[0] for loc 0 */  {  2,  1, -1, -1 },
         /* nav[1] for loc 1 */  {  0, -1, -1, -1 },
         /* nav[2] for loc 2 */  { -1,  0, -1, -1 }
        };

        createMagicItems();
    }

    private static void updateDisplay() {
        System.out.println(locations[currentLocale].getText());
    }

    private static void getCommand() {
        System.out.print("[" + moves + " moves, score " + score + "] ");
        Scanner inputReader = new Scanner(System.in);
        command = inputReader.nextLine();  // command is global.
    }

    private static void navigate() {
        final int INVALID = -1;
        int dir = INVALID;  // This will get set to a value > 0 if a direction command was entered.

        if (        command.equalsIgnoreCase("north") || command.equalsIgnoreCase("n") ) {
            dir = 0;
        } else if ( command.equalsIgnoreCase("south") || command.equalsIgnoreCase("s") ) {
            dir = 1;
        } else if ( command.equalsIgnoreCase("east")  || command.equalsIgnoreCase("e") ) {
            dir = 2;
        } else if ( command.equalsIgnoreCase("west")  || command.equalsIgnoreCase("w") ) {
            dir = 3;

        } else if ( command.equalsIgnoreCase("quit")  || command.equalsIgnoreCase("q")) {
            quit();
        } else if ( command.equalsIgnoreCase("help")  || command.equalsIgnoreCase("h")) {
            help();
        };

        if (dir > -1) {   // This means a dir was set.
            int newLocation = nav[currentLocale][dir];
            if (newLocation == INVALID) {
                System.out.println("You cannot go that way.");
            } else {
                currentLocale = newLocation;
                moves = moves + 1;
                // TODO: Deal with hasVisited and the score here.
            }
        }
    }

    private static void help() {
        System.out.println("The commands are as follows:");
        System.out.println("   n/north");
        System.out.println("   s/south");
        System.out.println("   q/quit");
    }

    private static void quit() {
        stillPlaying = false;
    }

    private static void createMagicItems() {
        // Create the list manager for our magic items.
        List0 magicItems  = new List0();
        magicItems.setName("Magic Items");
        magicItems.setDesc("These are the magic items.");
        magicItems.setHead(null);

        // Create some magic items and put them in the list.
        ListItem i1 = new ListItem();
        i1.setName("+2 ring");

        ListItem i2 = new ListItem();
        i2.setName("vorpal sword");

        ListItem i3 = new ListItem();
        i3.setName("cursed cloak of DOOM");

        // Link it all up.
        magicItems.setHead(i1);
        i1.setNext(i2);
        i2.setNext(i3);
        i3.setNext(null);

        System.out.println(magicItems.toString());
    }

}
--- Game --- --- --- --- --- --- --- --- --- --- ---


--- List0 --- --- --- --- --- --- --- --- --- --- ---
public class List0 {

    //
    // Public
    //

    // Constructor
    public List0() {
    }

    // Getters and Setters
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public String getDesc() {
        return desc;
    }
    public void setDesc(String desc) {
        this.desc = desc;
    }

    public ListItem getHead() {
        return head;
    }
    public void setHead(ListItem head) {
        this.head = head;
    }

    // Other methods
    @Override
    public String toString() {
        String retVal = new String();
        retVal = super.toString() + " name=" + this.name + " desc=" + this.desc + "\n";
        ListItem currentItem = this.head;
        while (currentItem != null) {
            retVal = retVal + "   " + currentItem.toString() + "\n";
            currentItem = currentItem.getNext();
        }
        return retVal;
    }


    //
    // Private
    //
    private String name;
    private String desc;
    private ListItem head;

}
--- List0 --- --- --- --- --- --- --- --- --- --- ---


--- ListItem --- --- --- --- --- --- --- --- --- --- ---
public class ListItem {

    //
    // Public
    //

    // Constructor
    public ListItem(){
    }

    // Getters and Setters
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public String getDesc() {
        return desc;
    }
    public void setDesc(String desc) {
        this.desc = desc;
    }

    public ListItem getNext() {
        return next;
    }
    public void setNext(ListItem next) {
        this.next = next;
    }

    // Other methods
    @Override
    public String toString() {
        return super.toString() + " name=" + this.name + " desc=" + this.desc;
    }


    //
    // Private
    //
    private String name;
    private String desc;
    private ListItem next = null;

}
--- ListItem --- --- --- --- --- --- --- --- --- --- ---


--- Locale --- --- --- --- --- --- --- --- --- --- ---
public class Locale {

    //
    // Public
    //

    // Constructor
    public Locale(int id) {
        this.id = id;
    }

    // Getters and Setters
    public int getId() {
        return this.id;
    }

    public String getText() {
        return this.name + "\n" + this.desc;
    }

    public String getName() {
        return this.name;
    }
    public void setName(String value) {
        this.name = value;
    }

    public String getDesc() {
        return this.desc;
    }
    public void setDesc(String value) {
        this.desc = value;
    }

    public boolean getHasVisited() {
        return hasVisited;
    }
    public void setHasVisited(boolean hasVisited) {
        this.hasVisited = hasVisited;
    }


    // Other methods
    @Override
    public String toString(){
        return "[Locale id="
                + this.id
                + " name="
                + this.name
                + " desc=" + this.desc
                + " hasVisited=" + this.hasVisited + "]";
    }

    //
    //  Private
    //
    private int     id;
    private String  name;
    private String  desc;
    private boolean hasVisited = false;
}
--- Locale --- --- --- --- --- --- --- --- --- --- ---


--- Space --- --- --- --- --- --- --- --- --- --- ---
public class Space extends Locale {       // Space IS-A Locale.

    //
    // Public
    //

    // Constructor
    public Space(int id){
        super(id);
    }

    // Getters and Setters
    public String getNearestPlanet() {
        return nearestPlanet;
    }
    public void setNearestPlanet(String nearestPlanet) {
        this.nearestPlanet = nearestPlanet;
    }


    @Override
    public String toString() {
        return "Space..." + super.toString() + " nearestPlanet=" + this.nearestPlanet;
    }

    //
    // Private
    //
    private String nearestPlanet;
}
--- Space --- --- --- --- --- --- --- --- --- --- ---