package CSVParse;
use strict;
use warnings;

sub new {
	my $self = shift;
	$self =
	  {
	   string_delim => '"',
	   escape_char => "\\",
	   field_delim => ',',
	   reg_delim => "\n"
	  };
	bless $self, "CSVParse";
	$self->{fh} = shift;
	return $self;
}

# supomos que ele esteja no início de uma coluna!
sub fetch_column {
	my $self = shift;
	my $context = 'raw_data';
	my @contexts = ();
	my $data = undef;

	while (1) {
		# char buffer
		my $buf;
		read($self->{fh},$buf,1) or do {
			$self->{EOF} = 1;
			last;
		};
		$self->{last_char_read} = $buf;
		if ($context eq 'escape') {
			$data = '' unless defined $data;
			$data .= $buf;
			$context = shift @contexts;
		} elsif ($context eq 'string') {
			if ($buf eq $self->{string_delim}) {
				$context = shift @contexts;
			} else {
				$data = '' unless defined $data;
				$data .= $buf;
			}
		} else {
			if ($buf eq $self->{escape_char}) {
				push @contexts, $context;
				$context = 'escape';
			} elsif ($buf eq $self->{string_delim}) {
				push @contexts, $context;
				$context = 'string';
			} elsif ($buf eq $self->{field_delim} ||
				 $buf eq $self->{reg_delim}) {
				# voltar um caractere
				seek($self->{fh},0,tell($self->{fh})-1);
				# sair do loop.
				last;
			} else {
				$data = '' unless defined $data;
				$data .= $buf;
			}
		}
	}

	return $data;
}

sub fetch_row {
	my $self = shift;
	if ($self->{EOF}) {
		return undef;
	}
	my @cols = ();
	# supomos que ele comece numa posição OK
	while (1) {
		my $col = $self->fetch_column();
		last if $self->{EOF};
		push @cols, $col;
		if ($self->{last_char_read} eq $self->{reg_delim}) {

			# sair do loop.
			last;
		}# elsif ($buf eq ($self->{field_delim})) { next; } else { next; }
	}
	return \@cols;
}

sub parse_file {
	my $self = shift;
	my @rows = ();
	while (1) {
		my $cols = $self->fetch_row();
		last unless defined $cols;
		push @rows,$cols;
	}
	return @rows;
}

1;