// CSE 143 Homework 6: 20 Questions

//

// To use the jGRASP debugger with this program, set a breakpoint

// and once the execution breaks, open 'this' or 'tq' on the left,

// then look at its variable 'tree'.  That's your QuestionTree.

// Drag your 'tree' over to the right to see a visualization of it.

// 

// (Your QuestionTree is constructed by this file on line 30.

// The overall loop to play games is around line 68.)

import java.io.*;

import java.util.Scanner;

/** A basic text user interface for the 20 questions game. */

public class QuestionMain implements UserInterface {

    public static void main(String[] args) {

        QuestionMain tq = new QuestionMain();

        tq.run();

    }

    // fields

    private Scanner console;

    private QuestionTree tree;

    /** Constructs a text user interface and its question tree. */

    public QuestionMain() {

        console = new Scanner(System.in);

        tree = new QuestionTree(this);

    }

    /**

     * Returns the user's response as a String.

     */

    public String nextLine() {

        return console.nextLine();

    }

    /** Prints the given string to the console. */

    public void print(String message) {

        System.out.print(message);

        System.out.print(" ");

    }

    /** Prints the given string to the console. */

    public void println(String message) {

        System.out.println(message);

    }

    /** Prints a blank line to the console. */

    public void println() {

        System.out.println();

    }

    /**

     * Waits for the user to answer a yes/no question on the console and returns the

     * user's response as a boolean (true for anything that starts with "y" or "Y").

     */

    public boolean nextBoolean() {

        String answer = console.nextLine();

        return answer.trim().toLowerCase().startsWith("y");

    }

    // private helper for overall game(s) loop

    private void run() {

        println("Welcome to the game of 20 Questions!");

        load();

        // "Think of an item, and I will guess it in N tries."

        println("\n" + BANNER_MESSAGE);

        do {

            // play one complete game

            println();      // blank line between games

            tree.play();

            print(PLAY_AGAIN_MESSAGE);

        } while (nextBoolean());   // prompt to play again

        // print overall stats

        // Games played: N ...  I have won: M

        println("\n" + String.format(STATUS_MESSAGE,

                tree.totalGames(), tree.gamesWon()));

        save();

    }

    // common code for asking the user whether they want to save or load

    private void load() {

        print(LOAD_MESSAGE);

        if (nextBoolean()) {

            print(SAVE_LOAD_FILENAME_MESSAGE);

            String filename = nextLine();

            try {

                Scanner in = new Scanner(new File(filename));

                tree.load(in);

            } catch (FileNotFoundException e) {

                System.out.println("Error: " + e.getMessage());

            }

        }

    }

    // common code for asking the user whether they want to save or load

    private void save() {

        print(SAVE_MESSAGE);

        if (nextBoolean()) {

            print(SAVE_LOAD_FILENAME_MESSAGE);

            String filename = nextLine();

            try {

                PrintStream out = new PrintStream(new File(filename));

                tree.save(out);

                out.close();

            } catch (FileNotFoundException e) {

                System.out.println("Error: " + e.getMessage());

            }

        }

    }

}