# $Id: Board.pm,v 1.1.1.1 2008/10/12 04:05:34 alamos Exp $
# The state is in an array
package TicTacToe::Board;
use strict;
use TicTacToe::Display;
use TicTacToe::Position qw(:all);

use base qw(Exporter);
use vars qw(@ISA $VERSION @EXPORT);

$VERSION='1.0';
@EXPORT = qw(&init_game &display_game &make_move &generate_moves &apply_move);

# Mapping to the opponent
my($opponent) = { x =>'o', o => 'x'};

sub apply_move {
    my($game,$move)=@_;
    my($value);
    my($result) = undef;
    my($new_game)= {
	position => &child_position($game->{position}, $move->{square}, $game->{player}),
	player   => $opponent->{$game->{player}},
	ply      => $game->{ply} + 1
	};
    if(game_won($game->{player}, $new_game->{position})) {
	$move->{value} = 100 - $new_game->{ply} ;
	$new_game->{result} = 'won';
    } else {
	# Number of occupied squares is the value
	my(@blanks) = grep /^ $/, @{$new_game->{position}};
	if($new_game->{ply} == 9) {
	    $new_game->{result}='stalemate';
	} 
	$move->{value} = $new_game->{ply};
    }
    return $new_game;
}

sub generate_moves {
    my($game)=@_;
    my(@squares) = &unoccupied_squares($game->{position});
    $game->{result}='stalemate'   unless(@squares);
    map { &make_move($_) } @squares;
}

sub make_move {
    my($square)=@_;
    return {
	square => $square,
	value => undef
	};
}

sub display_game {
    my($game)=@_;
    &display_position($game->{position});
    print "Ply: $game->{ply}\n";
    print "$game->{player} to move\n";
}

sub init_game {
    return {
	position   =>  &init_position,
	player     => 'o',
	ply        =>  0
	};
}

1;