###########################################################################
#
# mgppbuildproc.pm -- 
# A component of the Greenstone digital library software
# from the New Zealand Digital Library Project at the 
# University of Waikato, New Zealand.
#
# Copyright (C) 1999 New Zealand Digital Library Project
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
###########################################################################

# This document processor outputs a document
# for mgpp to process


package mgppbuildproc;

use basebuildproc;

BEGIN {
    @mgppbuildproc::ISA = ('basebuildproc');
}

#this must be the same as in mgppbuilder
our %level_map = ('document'=>'Doc',
		  'section'=>'Sec',
		  'paragraph'=>'Para');

sub new {
    my $class = shift @_;
    my $self = new basebuildproc (@_);

    # use a different index specification to the default
    $self->{'index'} = "text";

    $self->{'dontindex'} = {};
    $self->{'indexfieldmap'} = {};
    $self->{'indexfields'} = {}; # only put in the ones that are not specified directly in the index
    $self->{'strip_html'}=1;
    
    return bless $self, $class;
}


sub set_indexfieldmap {
    my $self = shift (@_);
    my ($indexmap) = @_;

    $self->{'indexfieldmap'} = $indexmap;
}

sub get_indexfieldmap {
    my $self = shift (@_);

    return $self->{'indexfieldmap'};
}

sub set_levels {
    my $self = shift (@_);
    my ($levels) = @_;

    $self->{'levels'} = $levels;
}

sub set_strip_html {
    my $self = shift (@_);
    my ($strip) = @_;
    $self->{'strip_html'}=$strip;
}


sub get_gdbm_level {
    my $self = shift (@_);
    
    #if a Section level index is not built, the gdbm file should be at doc 
    #level not Section
    if ($self->{'levels'}->{'section'}) {
	return "section";
    }
    return "document";
}


#sub find_paragraphs {
#    $_[1] =~ s/(<p\b)/<Paragraph>$1/gi;
#}

#this function strips the html tags from the doc if ($strip_html) and
# if ($para) replaces <p> with <Paragraph> tags.
# if both are false, the original text is returned
#assumes that <pre> and </pre> have no spaces, and removes all < and > inside
#these tags
sub preprocess_text {
    my $self = shift (@_);
    my ($text, $strip_html, $para) = @_;
    my ($outtext) = "";
    if ($strip_html) { 
	while ($text =~ /<([^>]*)>/ && $text ne "") {
	    
	    my $tag = $1;
	    $outtext .= $`." "; #add everything before the matched tag
	    $text = $'; #'everything after the matched tag
	    if ($para && $tag =~ /^\s*p\s/i) {
		$outtext .= $para;
	    }
	    elsif ($tag =~ /^pre$/) { # a pre tag
		$text =~ /<\/pre>/; # find the closing pre tag
		my $tmp_text = $`; #everything before the closing pre tag
		$text = $'; #'everything after the </pre>
		$tmp_text =~ s/[<>]//g; # remove all < and >
		$outtext.= $tmp_text . " ";
	    }
	}
    
	$outtext .= $text; # add any remaining text
	return $outtext;
    } #if strip_html

    #if ($para) {
	#$text =~ s/(<p\b)/$para$1/gi;
	#return $text;
   # }
    return $text;
}
	
    

sub filter_text {
    # $self->filter_text ($field, $new_text);
    # don't want to do anything for this version, however,
    # in a particular collection you might want to override
    # this method to post-process certain fields depending on
    # the field, or whether we are outputting it for indexing
}

sub text {
    my $self = shift (@_);
    my ($doc_obj) = @_;
    my $handle = $self->{'output_handle'};
    my $outhandle = $self->{'outhandle'};

    # only output this document if it is one to be indexed
    return if ($doc_obj->get_doc_type() ne "indexed_doc");

    my $indexed_doc = $self->is_subcollection_doc($doc_obj);
    
    # this is another document
    $self->{'num_docs'} += 1;

    # get the parameters for the output
    # split on : just in case there is subcoll and lang stuff
    my ($fields) = split (/:/, $self->{'index'});

    my ($documenttag) = "";
    my($documentendtag) = "";
    if ($self->{'levels'}->{'document'}) {
	$documenttag = "\n<". $level_map{'document'} . ">\n";
	$documentendtag = "\n</". $level_map{'document'} . ">\n";
    }
    my ($sectiontag) = "";
    if ($self->{'levels'}->{'section'}) {
	$sectiontag = "\n<". $level_map{'section'} . ">\n";
    }
    my ($paratag) = "";
    
    if ($self->{'levels'}->{'paragraph'}) {
	if ($self->{'strip_html'}) {
	    $paratag = "<". $level_map{'paragraph'} . ">";
	} else {
	    print $outhandle "Paragraph level can not be used with no_strip_html!. Not indexing Paragraphs.\n";
	}
    }

    my $doc_section = 0; # just for this document
    
    my $text = $documenttag;
   
    # get the text for this document
    my $section = $doc_obj->get_top_section();
    while (defined $section) {
	# update a few statistics
	$doc_section++;
	$self->{'num_sections'} += 1;
	$text .= "$sectiontag";

	if ($indexed_doc) {
	    if ($self->{'indexing_text'}) {
		$text .= "$paratag"; # only add para tags for indexing
		# note that we assume that metadata will not be asked for for the compressed text, so we add para tags without checking for indexing_text
	    }
	    $self->{'num_bytes'} += $doc_obj->get_text_length ($section);
	    foreach my $field (split (/,/, $fields)) {
		# only deal with this field if it doesn't start with top or
		# this is the first section
		my $real_field = $field;
		if (!($real_field =~ s/^top//) || ($doc_section == 1)) {
		    my $new_text = ""; 
		    my $tmp_text = "";
		    if ($real_field eq "text") {
			if ($self->{'indexing_text'}) { #tag the text with <Text>...</Text>, add the <Paragraph> tags and strip out html if needed
			    $new_text .= "$paratag<TX>\n";
			    $tmp_text .= $doc_obj->get_text ($section);
			    $tmp_text = $self->preprocess_text($tmp_text, $self->{'strip_html'}, "</TX>$paratag<TX>");
			    
			    $new_text .= "$tmp_text</TX>\n";
			    #if (!defined $self->{'indexfields'}->{'TextOnly'}) {
				#$self->{'indexfields'}->{'TextOnly'} = 1;   
			    #}
			}
			else { # leave html stuff in, and dont add Paragraph tags - never retrieve paras at the moment
			    $new_text .= $doc_obj->get_text ($section) if $self->{'store_text'};
			}
		    } else { # metadata field
			if ($real_field eq "allfields") { #ignore
			}
			elsif ($real_field eq "metadata") { # insert all metadata 
			    #except gsdl stuff
			    my $shortname = "";
			    my $metadata = $doc_obj->get_all_metadata ($section);
			    foreach my $pair (@$metadata) {
				my ($mfield, $mvalue) = (@$pair);
				# check fields here, maybe others dont want - change to use dontindex!!
				if ($mfield ne "Identifier" 
				    && $mfield !~ /^gsdl/ 
				    && $mfield ne "classifytype"
				    && $mfield ne "assocfilepath"
				    && defined $mvalue && $mvalue ne "") {
				    
				    if (defined $self->{'indexfieldmap'}->{$mfield}) {
					$shortname = $self->{'indexfieldmap'}->{$mfield};
				    }
				    else {
					$shortname = $self->create_shortname($mfield);
					$self->{'indexfieldmap'}->{$mfield} = $shortname;
					$self->{'indexfieldmap'}->{$shortname} = 1;
				    }	   
				    $new_text .= "$paratag<$shortname>$mvalue</$shortname>\n";
				    if (!defined $self->{'indexfields'}->{$mfield}) {
					$self->{'indexfields'}->{$mfield} = 1;
				    }				    
				}
			    }
			    
			}
			else { #individual metadata specified
			    my $shortname="";
			    #if (!defined $self->{'indexfields'}->{$real_field}) {
				#$self->{'indexfields'}->{$real_field} = 1;
			    #}
			    if (defined $self->{'indexfieldmap'}->{$real_field}) {
				$shortname = $self->{'indexfieldmap'}->{$real_field};
			    }
			    else {
				$shortname = $self->create_shortname($real_field);
				$self->{'indexfieldmap'}->{$real_field} = $shortname;
				$self->{'indexfieldmap'}->{$shortname} = 1;
			    }
			    my @section_metadata = @{$doc_obj->get_metadata ($section, $real_field)};
			    if ($self->{'indexing_text'} && defined ($self->{'sections_index_document_metadata'})) {
				if ($self->{'sections_index_document_metadata'} eq "always" || ( scalar(@section_metadata) == 0 && $self->{'sections_index_document_metadata'} eq "unless_section_metadata_exists")) {
				    push (@section_metadata, @{$doc_obj->get_metadata ($doc_obj->get_top_section(), $real_field)});
				}
			    }
			    foreach my $item (@section_metadata) {
			    #foreach my $item (@{$doc_obj->get_metadata ($section, $real_field)}) {
				$new_text .= "$paratag<$shortname>$item</$shortname>\n";
			    }
			}

		    }
		    
		    # filter the text
		    $self->filter_text ($field, $new_text);

		    $self->{'num_processed_bytes'} += length ($new_text);
		    $text .= "$new_text";
		}
	    }
	} # if (indexed_doc)
	
	$section = $doc_obj->get_next_section($section);
    } #while defined section
    print $handle "$text\n$documentendtag"; 
    
}

#chooses the first two letters or digits for the shortname
#now ignores non-letdig characters
sub create_shortname {
    my $self = shift(@_);
    
    my ($realname) = @_;
    #take the first two chars
    my $shortname;
    if ($realname =~ /^[^\w]*(\w)[^\w]*(\w)/) {
	$shortname = "$1$2";
    } else {
	# there aren't two letdig's in the field - try arbitrary combinations
	$realname = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	$shortname = "AB";
    }
    $shortname =~ tr/a-z/A-Z/;

    #if already used, take the first and third letdigs and so on
    my $count = 1;
    while (defined $self->{'indexfieldmap'}->{$shortname}) {
	if ($realname =~ /^[^\w]*(\w)([^\w]*\w){$count}[^\w]*(\w)/) {
	    $shortname = "$1$3";
	    $count++;
	    $shortname =~ tr/a-z/A-Z/;
	
	}
	else {
	    #remove up to and incl the first letdig
	    $realname =~ s/^[^\w]*\w//;
	    $count = 0;
	}
    }

    return $shortname;
}

1;