package Kea;

use strict;

# This function is called by BasPlug.pm when a flag in a collection
# configuration document specifies that keyphrase metadata must be gathered for
# that collection.
# It is passed as arguments, the documents text and possibly some options for
# how the keyphrase data is to be collected if the keyphrase option flag was
# set in the collection configuration file.  This module then writes the
# documents text to a file because the stand-alone program Kea which will be
# called to do the actual extraction of the keyphrases expects a file argument.
# Once Kea has been called upon, the file containing the keyphrase data
# gathered by Kea should be stored in gsdl/tmp and this file is read, the data
# we are interested in is extracted and passed back to BasPlug.pm in an
# appropriate format.

sub extract_KeyPhrases {

    my $gsdlhome = $ENV{'GSDLHOME'}; 
    my $doc = shift(@_); #documents text  
    my $args = shift(@_); #any options
    my @optionlist = split(/ +/, $args) if (defined($args)); #list of options
    my $suffix = 'kea'; #default file will be called .kea
    my @kea_options;
    my @keylist; 
    my @stemlist;


    foreach my $element (@optionlist){ #for each option
	my ($option, $file) = split(/,/, $element); #split option letter and file (if file exist)

	$option  = "-".$option; #place dash in front of option
	push @kea_options, $option;
	if (defined($file)) {
	    push @kea_options, $file;
	}

	if ($option eq '-E')  # option is extension (suffix) option
	    { $suffix = $file }
    }

    # print STDERR "Using output suffix: $suffix\n"; 

    # remove all HTML tags
    $doc =~ s/<[ph][^>]*>/\n/sgi; # replace headings/paragraphs with newline
    $doc =~ s/<[^>]*>/ /sgi; # replace all others with a space

    # &gt; lt amp
    $doc =~ s/\&(?:gt|lt|amp)\;/ /gi;

    my $tmpfile="$gsdlhome/tmp/doc.txt";
    open(OUT, ">$tmpfile") or die "Kea.pm could not create doc.txt: $!\n";  
    print OUT $doc;
    close(OUT);

    # call Kea with specifed options
    system("$gsdlhome/perllib/Kea-1.1.4/Kea", @kea_options,
	   $tmpfile); 

    unlink($tmpfile); # don't need this file anymore

    # read doc.kea with keywords
    my $inputfile="$gsdlhome/tmp/doc.$suffix";

    # If this file doesn't exist, then either an option was wrongly specified
    # or no keyphrases were found
    open(IN, "<$inputfile") or return ();

    while(<IN>){
	chomp;
	my @key = split(/\t/); #split into array separated by a tab
	push(@keylist, $key[0]); #add to list of keywords
	push(@stemlist, $key[1]); #add to list of stems  
    }
    close(IN);

    #put data into appropriate format 
    my $keylistref = join(", ", @keylist);
    my $stemlistref = join(", ", @stemlist);	
 
    # delete doc.extension so that in future it will not be opened and read
    unlink($inputfile);

    # return keywords + stems to basplug
    return ($keylistref, $stemlistref);
}



1;