/**
 *  This class is the main class of the "World of Zuul" application.
 *  "World of Zuul" is a very simple, text based adventure game.  Users
 *  can walk around some scenery. That's all. It should really be extended
 *  to make it more interesting!
 *
 *  To play this game, create an instance of this class and call the "play"
 *  method.
 *
 *  This main class creates and initialises all the others: it creates all
 *  rooms, creates the parser and starts the game.  It also evaluates and
 *  executes the commands that the parser returns.
 *
 * @author  Michael Kölling and David J. Barnes
 * @version 2016.02.29
 */

public class Game
{
    private Parser parser;
    private Room currentRoom;

    /**
     * Create the game and initialise its internal map.
     */
    public Game()
    {
        createRooms();
        parser = new Parser();
    }
    /**
     * Create all the rooms and link their exits together.
     */
    private void createRooms()
    {
        Room outside, theater, pub, lab, office, stairsFloor1, corridor1, stairsFloor2, library, canteen, gym, classroom, examHall;
        Item textbooks, studentID;
        // create the rooms
        outside = new Room("outside the main entrance of the university");
        theater = new Room("in a lecture theater");
        pub = new Room("in the campus pub");
        lab = new Room("in a computing lab");
        office = new Room("in the computing admin office, you can pick up your student ID from here");
        stairsFloor1 = new Room("by some stairs that lead up to floor 1");
        corridor1 = new Room("in the corridor");
        classroom = new Room("in a classroom");
        library = new Room("in the library, there may be some useful textbooks");
        canteen = new Room("in the canteen");
        gym = new Room("in the gym");
        stairsFloor2 = new Room("by some stairs that lead up to the exam hall");
        examHall = new Room("in the exam hall");

        // initialise room exits
        outside.setExit("east", theater);
        outside.setExit("south", lab);
        outside.setExit("west", pub);

        theater.setExit("west", outside);

        pub.setExit("east", outside);
        pub.setExit("south", stairsFloor1);

        lab.setExit("north", outside);
        lab.setExit("east", office);

        office.setExit("west", lab);

        stairsFloor1.setExit("up", corridor1);
        stairsFloor1.setExit("north", pub);
        corridor1.setExit("down" , stairsFloor1);
        corridor1.setExit("east" , classroom);

        classroom.setExit("north", library);
        classroom.setExit("east", canteen);
        classroom.setExit("west", corridor1);

        canteen.setExit("north", gym);
        canteen.setExit("west", classroom);

        gym.setExit("south", canteen);
        gym.setExit("west", library);

        library.setExit("east", gym);
        library.setExit("south", classroom);
        library.setExit("west", stairsFloor2);

        stairsFloor2.setExit("up", examHall);
        stairsFloor2.setExit("east", library);

        examHall.setExit("down", stairsFloor2);


        textbooks = new Item("There are some textbooks");
        studentID = new Item("This is your studentID");

        textbooks.setItem(lab, textbooks);
        studentID.setItem(office, studentID);

        currentRoom = outside;  // start game outside
    }

    /**
     *  Main play routine.  Loops until end of play.
     */
    public void play()
    {
        printWelcome();

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

        boolean finished = false;
        while (! finished) {
            Command command = parser.getCommand();
            finished = processCommand(command);
        }
        System.out.println("Thank you for playing.  Good bye.");
    }

    /**
     * Print out the opening message for the player.
     */
    private void printWelcome()
    {
        System.out.println();
        System.out.println("Welcome to the World of Zuul!");
        System.out.println("World of Zuul is a new, incredibly boring adventure game.");
        System.out.println("Type 'help' if you need help.");
        System.out.println();
        System.out.println(currentRoom.getLongDescription());
    }

    /**
     * Given a command, process (that is: execute) the command.
     * @param command The command to be processed.
     * @return true If the command ends the game, false otherwise.
     */
    private boolean processCommand(Command command)
    {
        boolean wantToQuit = false;

        if(command.isUnknown()) {
            System.out.println("I don't know what you mean...");
            return false;
        }

        String commandWord = command.getCommandWord();
        if (commandWord.equals("help")) {
            printHelp();
        }
        else if (commandWord.equals("go")) {
            goRoom(command);
        }
        else if (commandWord.equals("quit")) {
            wantToQuit = quit(command);
        }
        //else if (commandWord.equals("carry")){

        // else command not recognised.
        return wantToQuit;
    }

    // implementations of user commands:

    /**
     * Print out some help information.
     * Here we print some stupid, cryptic message and a list of the
     * command words.
     */
    private void printHelp()
    {
        System.out.println("You are lost. You are alone. You wander");
        System.out.println("around at the university.");
        System.out.println();
        System.out.println("Your command words are:");
        parser.showCommands();
    }

    /**
     * Try to in to one direction. If there is an exit, enter the new
     * room, otherwise print an error message.
     */
    private void goRoom(Command command)
    {
        if(!command.hasSecondWord()) {
            // if there is no second word, we don't know where to go...
            System.out.println("Go where?");
            return;
        }

        String direction = command.getSecondWord();

        // Try to leave current room.
        Room nextRoom = currentRoom.getExit(direction);

        if (nextRoom == null) {
            System.out.println("There is no door!");
        }
        else {
            currentRoom = nextRoom;
            System.out.println(currentRoom.getLongDescription());


        }
    }
    /**
     * "Quit" was entered. Check the rest of the command to see
     * whether we really quit the game.
     * @return true, if this command quits the game, false otherwise.
     */
    private boolean quit(Command command)
    {
        if(command.hasSecondWord()) {
            System.out.println("Quit what?");
            return false;
        }
        else {
            return true;  // signal that we want to quit
        }
    }
}