File Coverage

blib/lib/Games/LMSolve/Alice.pm

Criterion	Covered	Total	%
statement	12	113	10.6
branch	0	28	0.0
condition	0	15	0.0
subroutine	4	14	28.5
pod	8	8	100.0
total	24	178	13.4

package Games::LMSolve::Alice;
$Games::LMSolve::Alice::VERSION = '0.14.0';
use strict;
use warnings;

use Games::LMSolve::Base qw(%cell_dirs);

use vars qw(@ISA);

@ISA = qw(Games::LMSolve::Base);

my %cell_flags = (
    'ADD'   => 1,
    'SUB'   => -1,
    'GOAL'  => 0,
    'START' => 1,
    'BLANK' => 0,
);

sub input_board
{
    my $self = shift;

    my $filename = shift;

    my $spec = {
        'dims'   => { 'type' => "xy(integer)", 'required' => 1 },
        'layout' => { 'type' => "layout",      'required' => 1 },
    };

    my $input_obj    = Games::LMSolve::Input->new();
    my $input_fields = $input_obj->input_board( $filename, $spec );

    my ( $width, $height ) =
        @{ $input_fields->{'dims'}->{'value'} }{ 'x', 'y' };

    my (@board);

    my $line;
    my $line_number = 0;
    my $lines_ref   = $input_fields->{'layout'}->{'value'};

    my $read_line = sub {
        if ( scalar(@$lines_ref) == $line_number )
        {
            return 0;
        }
        $line = $lines_ref->[$line_number];
        $line_number++;
        return 1;
    };

    my $gen_exception = sub {
        my $text = shift;
        die "$text on $filename at line "
            . ( $input_fields->{'layout'}->{'line_num'} + $line_number + 1 )
            . "!\n";
    };

    my ( $y,       $x );
    my ( $start_x, $start_y );

    $y = 0;
    $x = 0;

INPUT_LOOP: while ( $read_line->() )
    {
        while ( length($line) > 0 )
        {
            $line =~ s/^\s+//;
            if ( $line =~ /\S/ )
            {
                if ( $line =~ /^\[([^\]]*)\]/ )
                {
                    my $flags_string = uc($1);
                    my @flags        = ( split( /,/, $flags_string ) );
                    my @dirs = ( grep { exists( $cell_dirs{$_} ) } @flags );
                    my @flag_flags =
                        ( grep { exists( $cell_flags{$_} ) } @flags );
                    my @unknown_flags = (
                        grep {
                                   ( !exists( $cell_dirs{$_} ) )
                                && ( !exists( $cell_flags{$_} ) )
                        } @flags
                    );
                    if ( scalar(@unknown_flags) )
                    {
                        $gen_exception->( "Unknown Flags on Cell ("
                                . join( ",", @unknown_flags )
                                . ")" );
                    }
                    $board[$y][$x] = {
                        'dirs' => { map { $_ => $cell_dirs{$_} } @dirs },
                        'flags' =>
                            { map { $_ => $cell_flags{$_} } @flag_flags },
                    };

                    if ( exists( $board[$y][$x]->{'flags'}->{'START'} ) )
                    {
                        if ( defined($start_x) )
                        {
                            $gen_exception->("Two starts were defined!\n");
                        }
                        $start_x = $x;
                        $start_y = $y;
                    }
                    $x++;
                    if ( $x == $width )
                    {
                        $x = 0;
                        $y++;
                        if ( $y == $height )
                        {
                            last INPUT_LOOP;
                        }
                    }
                    $line =~ s/^.*?\]//;
                }
                elsif ( $line =~ /^#/ )
                {
                    # Do nothing - it's a comment
                    $line = "";
                }
                else
                {
                    $gen_exception->("Junk at Line");
                }
            }
        }
    }

    if ( $y != $height )
    {
        $gen_exception->(
            "Input Terminated Prematurely after reading y=$y x=$x");
    }

    if ( !defined($start_x) )
    {
        $gen_exception->("The Starting Position was not defined anywhere");
    }

    $self->{'height'} = $height;
    $self->{'width'}  = $width;
    $self->{'board'}  = \@board;

    return [ $start_x, $start_y, 1 ];
}

# A function that accepts the expanded state (as an array ref)
# and returns an atom that represents it.
sub pack_state
{
    my $self         = shift;
    my $state_vector = shift;
    return pack( "ccc", @{$state_vector} );
}

# A function that accepts an atom that represents a state
# and returns an array ref that represents it.
sub unpack_state
{
    my $self  = shift;
    my $state = shift;
    return [ unpack( "ccc", $state ) ];
}

# Accept an atom that represents a state and output a
# user-readable string that describes it.
sub display_state
{
    my $self  = shift;
    my $state = shift;
    my ( $x, $y, $d ) = @{ $self->unpack_state($state) };
    return sprintf( "X = %i ; Y = %i ; d = %i", $x + 1, $y + 1, $d );
}

# This function checks if a state it receives as an argument is a
# dead-end one.
sub check_if_unsolvable
{
    my $self   = shift;
    my $coords = shift;
    return ( $coords->[2] == 0 );
}

sub check_if_final_state
{
    my $self = shift;

    my $coords = shift;
    return
        exists(
        $self->{'board'}->[ $coords->[1] ][ $coords->[0] ]->{'flags'}->{'GOAL'}
        );
}

# This function enumerates the moves accessible to the state.
# If it returns a move, it still does not mean that it is a valid
# one. I.e: it is possible that it is illegal to perform it.
sub enumerate_moves
{
    my $self = shift;

    my $coords = shift;
    return
        keys(
        %{ $self->{'board'}->[ $coords->[1] ][ $coords->[0] ]->{'dirs'} } );
}

# This function accepts a state and a move. It tries to perform the
# move on the state. If it is succesful, it returns the new state.
#
# Else, it returns undef to indicate that the move is not possible.
sub perform_move
{
    my $self = shift;

    my $coords = shift;
    my $m      = shift;

    my $offsets    = [ map { $_ * $coords->[2] } @{ $cell_dirs{$m} } ];
    my @new_coords = @$coords;
    $new_coords[0] += $offsets->[0];
    $new_coords[1] += $offsets->[1];

    my $new_cell =
        $self->{'board'}->[ $new_coords[1] ][ $new_coords[0] ]->{'flags'};

    # Check if we are out of the bounds of the board.
    if (   ( $new_coords[0] < 0 )
        || ( $new_coords[0] >= $self->{'width'} )
        || ( $new_coords[1] < 0 )
        || ( $new_coords[1] >= $self->{'height'} )
        || exists( $new_cell->{'BLANK'} ) )
    {
        return;
    }

    if ( exists( $new_cell->{'ADD'} ) )
    {
        $new_coords[2]++;
    }
    elsif ( exists( $new_cell->{'SUB'} ) )
    {
        $new_coords[2]--;
    }

    return [@new_coords];
}

1;

__END__