import java.util.*;

public class AdventureDemo {
  public static void main(String[] args) {
    Adventure game = new Adventure();
    game.play();
  }
}

class Adventure {
  // instance variables (aka "fields")
  private Room currentRoom;
  private Scanner scanner = new Scanner(System.in);
  private boolean gameOver;
  private ArrayList<Thing> inventory;
  
  public Adventure() {
    Room rm5419a = new Room("5419a lab");
    Room rm5419b = new Room("5419b lab");
    Room hall5400 = new Room("5400 hallway");
    rm5419b.setExit(Dir.SOUTH, hall5400);
    rm5419b.setExit(Dir.WEST,  rm5419a);
    hall5400.setExit(Dir.NORTH, rm5419b);
    rm5419a.setExit(Dir.EAST,  rm5419b);
    
    Thing johnTran = new Thing("JohnTran");
    rm5419b.addThing(johnTran);
    Thing projector = new Thing("Projector");
    rm5419b.addThing(projector);
    
    currentRoom = rm5419b;
    inventory = new ArrayList<Thing>();
    gameOver = false;
  }

  private void printInventory() {
    System.out.print("You are carrying:  ");
    if (this.inventory.size() == 0)
      System.out.println("Nothing!");
    else
      System.out.println(this.inventory);
  }
  
  private void printObjectsInRoom() {
    System.out.println("You can see:  " + 
                       currentRoom.getThings());
  }
  
  private void printLegalExits() {
    System.out.print("You can go: ");
    boolean hasExits = false;
    for (int dir=0; dir<Dir.DIRS; dir++) {
      Room exitRoom = currentRoom.getExit(dir);
      if (exitRoom != null) {
        if (hasExits == true)
          System.out.print(", ");
        System.out.print(Dir.getDirName(dir));
        hasExits = true;
      }
    }
    if (hasExits == false)
      System.out.print("no directions!");
    System.out.println();
  }
  
  private void doGet(String thingName) {
    Thing thing = currentRoom.findThing(thingName);
    if (thing == null) {
      System.out.println("I don't see that here!");
      return;
    }
    currentRoom.removeThing(thing);
    inventory.add(thing);
  }
  
  private void doGo(String noun) {
    int dir = Dir.getDir(noun);
    if (dir < 0) {
      System.out.println("I do not know that direction!");
      return;
    }
    Room newRoom = currentRoom.getExit(dir);
    if (newRoom == null) {
      System.out.println("I cannot go in that direction!");
      return;
    }
    currentRoom = newRoom;
  }
  
  private void doQuit() {
    gameOver = true;
    System.out.println("Goodbye!");
  }
  
  private void doCommand() {
    System.out.print("Your command --> ");
    String cmd = scanner.nextLine().toLowerCase();
    String[] cmdWords = cmd.split(" ");
    String verb = cmdWords[0];
    String noun = (cmdWords.length < 2 ? "" : cmdWords[1]);
    if (verb.equals("go")) doGo(noun);
    else if (verb.equals("get")) doGet(noun);
    else if (verb.equals("n")) doGo("north");
    else if (verb.equals("quit")) doQuit();
    else if (verb.equals("q")) doQuit();
    else System.out.println("I don't know how to " + verb);
  }
  
  public void play() {
    while (gameOver == false) {
      System.out.println("\nYou are in " + currentRoom);
      printObjectsInRoom();
      printInventory();
      printLegalExits();
      doCommand();
    }
    System.out.println("You win!");
  }
}

class Dir {
  public static final int NORTH = 0;
  public static final int SOUTH = 1;
  public static final int EAST  = 2;
  public static final int WEST  = 3;
  public static final int UP    = 4;
  public static final int DOWN  = 5;
  public static final int DIRS = 6;
  
  private static final String[] dirNames = {
    "North", "South", "East", "West", "Up", "Down"
  };
  
  public static String getDirName(int dir) {
    return dirNames[dir];
  }
  
  public static int getDir(String dirName) {
    for (int i=0; i<dirNames.length; i++)
      if (dirNames[i].toLowerCase().equals(dirName))
        return i;
    return -1;
  }
}

class Thing {
  // fields (aka "instance variables")
  private String name;
  
  // constructor
  public Thing(String name) {
    this.name = name;
  }
  
  // accessor
  public String getName() {
    return this.name;
  }
  
  // toString method
  public String toString() {
    return this.name;
  }
}

class Room {
  // fields (aka "instance variables")
  private String name;
  private Room[] exits;
  private ArrayList<Thing> things; // like Thing[]
  
  // constructor
  public Room(String name) {
    this.name = name;
    this.exits = new Room[Dir.DIRS];
    this.things = new ArrayList<Thing>();
  }
  
  // accessor for name
  public String getName() {
    return this.name;
  }

  // accessor and mutator for this.things
  public ArrayList<Thing> getThings() {
    return this.things;
  }
  
  public Thing findThing(String thingName) {
    for (int i=0; i<this.things.size(); i++) {
      Thing thing = this.things.get(i); 
      if (thing.getName().toLowerCase().equals(thingName))
        return thing;
    }
    return null;
  }
  
  public void addThing(Thing thing) {
    this.things.add(thing);
  }
  
  public void removeThing(Thing thing) {
    this.things.remove(thing);
  }
  
  // accessor and mutator for this.exits  
  public Room getExit(int dir) {
    return this.exits[dir];
  }

  public void setExit(int dir, Room room) {
    this.exits[dir] = room;
  }
  
  // toString method
  public String toString() {
    return this.name;
  }
}