import java.util.HashMap;
import java.util.Scanner;

/**
 *  This class is the main class of the "Exciting Campus" application.
 *  "Exciting Campus" is a very simple, text based adventure game.  Users
 *  can walk around some locations. That's all. It should really be extended
 *  to make it more interesting!  The original version was "World of Zuul".
 * 
 *  This main class creates and initialises all the others: it creates all
 *  rooms, a Game, and plays the Game.  The Game evaluates and
 *  executes the commands that the parser returns.
 *  
 *  This version is modified by Andrew Harrington to use the UI and FileUtil
 *  utility classes.  Room data comes from a text file rather than being
 *  hard-coded into the program.  This implementation also allows all rooms
 *  to be accessed by name using the HashMap rooms in the Game class.
 *  
 *  A main method is also provided in the Game class.
 *  All commands are executed by classes satisfying the Response interface,
 *  so the main class does not have the code for the commands.
 *  The CommandMapper class maps command words to Responses.
 *  The Parser and CommandMapper classes are static.
 * 
 * @author  Michael Kolling and David J. Barnes
 * @version 2006.03.30
 */

public class Game 
{
    private Room currentRoom;
    private HashMap<String, Room> rooms; //allows all rooms to be found by name
    private String welcomeString;
    
    /** Make a Game playable from the command line.
     * @param args No commandline arguments needed
     */
    public static void main(String[] args) {
        Game game = new Game("startData.txt");
        game.play();
    }
    
    /** Return the current room. */
    public Room getCurrentRoom() {
        return currentRoom;
    }
    
    /**
     * Return the Room associated with a name.
     * @param roomName The name of the desired Room.
     * @return the associated Room.
     */
    public Room getNamedRoom(String roomName) {
        return rooms.get(roomName);
    }
    
    /**
     * Set the current room.
     * @param newRoom The new current Room.
     */
    public void setCurrentRoom(Room newRoom) {
        currentRoom = newRoom;
    }
    
    /**
     * Create the game and initialise its internal map
     * @param worldData World initialization data file name.
     */
    public Game(String worldData)
    {   // world data: starting room line,
        //    welcome and help intro paragraphs, then Room data
        Scanner dataIn = ResourceUtil.openFileScanner(worldData);
        String startingRoom = FileUtil.getNonCommentLine(dataIn).trim();
        welcomeString = FileUtil.readParagraph(dataIn);
        String helpIntro = FileUtil.readParagraph(dataIn);
        rooms = Room.createRooms(dataIn);
        currentRoom = rooms.get(startingRoom);

        CommandMapper.init(this, helpIntro); // data for some Responses
    }

    /**
     *  Main play routine.  Loops until end of play.
     */
    public void play() 
    {
        System.out.println(welcomeString);
        System.out.println(currentRoom.getLongDescription());

        // Enter the main command loop.  Here we repeatedly read commands and
        // execute them until the game is over.

        while (! processCommand())
            ;  // convention with isolated semicolon for an empty loop
        System.out.println("Thank you for playing.  Good bye.");
    }

    /**
     * Main loop actions: Get user input ... execute the command.
      * @return true if the command ends the game, false otherwise.
     */
    private boolean processCommand()
    {
        String line = UI.promptLine("> ");

        String[] tokens = line.trim().split("\\s+");

        if ((tokens.length == 0) || !CommandMapper.isCommand(tokens[0])) {
            System.out.println("I don't know what you mean...");
            return false;
        }

        Response response = CommandMapper.getResponse(tokens[0]);
        return response.execute(tokens);
    }

}