// CSE 143, Winter 2009, Marty Stepp
// Homework 7: 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.*;

/** 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);
    }
    
    /**
     * Asks the user a question on the console and returns the user's
     * response as a String.
     */
    public String ask(String question) {
        System.out.print(question.trim() + " ");
        return console.nextLine();
    }

    /** Prints the given string to the console. */
    public void println(String message) {
        System.out.println(message);
    }

    /**
     * Asks the user 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 yesNo(String question) {
        System.out.print(question.trim() + " ");
        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();
        } while (yesNo(PLAY_AGAIN_MESSAGE));   // 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() {
        if (yesNo(LOAD_MESSAGE)) {
            String filename = ask(SAVE_LOAD_FILENAME_MESSAGE);
            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() {
        if (yesNo(SAVE_MESSAGE)) {
            String filename = ask(SAVE_LOAD_FILENAME_MESSAGE);
            try {
                PrintStream out = new PrintStream(new File(filename));
                tree.save(out);
                out.close();
            } catch (FileNotFoundException e) {
                System.out.println("Error: " + e.getMessage());
            }
        }
    }
}