package Google::Charts::Encoding;

# To use this:
# my $enc = Google::Charts::Encoding->new( $string_to_encode );
# my $result = $enc->encode();

# To obtain the last result:
# my $last_result = $enc->encoded();

# You may also pass the encode string to $enc->encode() 
# instead of to $enc->new();
# my $result = enc->encode( $string_to_encode );


use strict;
use warnings;

use POSIX;
use List::Util qw[ min max ];

# Constructor: Pass the string to be encoded, or nothing (in which
# case you must pass the string directly to $obj->encode()

sub new {
	my $self = {};
	$self->{encode_string} = $_[0] || undef;
	$self->{encoded} = undef;
	bless( $self );
	return $self;
}


# If the string to be encoded was passed to $obj->new(), no 
# parameter is needed for calling $obj->encode().  If nothing
# was passed to $obj->new(), you will need to pass the string 
# as a parameter here.

sub encode {
	my $self = shift;
	my $to_encode = $_[0] || $self->{encode_string};
	defined( $to_encode ) 
		or die "Nothing to encode in __PACKAGE__ encode()\n";
	my @characters = ( 
            'A' .. 'Z' , 
            'a' .. 'z', 
            '0' .. '9', 
            '-', 
            '.' 
        );
	my @series = split( /\|/, $to_encode );
	my @seriesmax = split( /\||\,/, $to_encode );
	my $max = max( @seriesmax );
	my $returnstring = '';
        foreach ( @series ){
		my @values = split( /\,/, $_ );
		my $encoding = '';
		foreach my $value ( @values ){
			chomp $value;
			$value = ( $value / $max ) * 4095;
			my $first = floor( $value / 64 );
			my $second = $value % 64;
			$encoding .= $characters[ $first ] . 
                                     $characters[ $second ];
	        }
            $returnstring .= $encoding . ',';
        }
	my $encoded = substr( $returnstring, 0, -1 );
	$self->{encoded} = $encoded;
	return $encoded;
}


# Getter for the most recent call to encode().
sub encoded {
	my $self = shift;
	if( defined( $self->{encoded} )  ) {
		return $self->{encoded}
	} else {
		die "Nothing has been encoded yet in __PACKAGE__\n";
	}
}

1;