###########################################################################
#
# plugin.pm -- functions to handle using plugins
# 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.
#
###########################################################################

package plugin;

use strict; # to pick up typos and undeclared variables...
no strict 'refs'; # ...but allow filehandles to be variables and vice versa
no strict 'subs';

require util;
use gsprintf 'gsprintf';

# global variables
my $stats = {'num_processed' => 0,
	     'num_blocked' => 0,
	     'num_not_processed' => 0,
	     'num_not_recognised' => 0,
	     'num_archives' => 0
	     };

#globaloptions contains any options that should be passed to all plugins
my ($verbosity, $outhandle, $failhandle, $globaloptions);

sub load_plugin_for_info {
    my ($pluginname) = shift @_;

    # find the plugin
    my $colplugname = &util::filename_cat($ENV{'GSDLCOLLECTDIR'},"perllib/plugins", 
					  "${pluginname}.pm");
    my $mainplugname = &util::filename_cat($ENV{'GSDLHOME'},"perllib/plugins", 
					   "${pluginname}.pm");
    if (-e $colplugname) { require $colplugname; }
    elsif (-e $mainplugname) { require $mainplugname; }
    else {
	&gsprintf(STDERR, "{plugin.could_not_find_plugin}\n",
		 $pluginname);
	die "\n";
    }

    # create a plugin object
    my ($plugobj);
    my $options = "-gsdlinfo";
    
    eval ("\$plugobj = new \$pluginname([],[$options])");
    die "$@" if $@;

    return $plugobj;
}

sub load_plugins {
    my ($plugin_list) = shift @_;
    my $incremental;
    ($verbosity, $outhandle, $failhandle, $globaloptions, $incremental) = @_; # globals
    my @plugin_objects = ();
    $incremental = 0 unless (defined $incremental && $incremental == 1);
    $verbosity = 2 unless defined $verbosity;
    $outhandle = 'STDERR' unless defined $outhandle;
    $failhandle = 'STDERR' unless defined $failhandle;

    map { $_ = "\"$_\""; } @$globaloptions;
    my $globals = join (",", @$globaloptions);

    foreach my $pluginoptions (@$plugin_list) {
	my $pluginname = shift @$pluginoptions;
	next unless defined $pluginname;

	# find the plugin
	my $colplugname = &util::filename_cat($ENV{'GSDLCOLLECTDIR'},"perllib/plugins", 
					      "${pluginname}.pm");
	my $mainplugname = &util::filename_cat($ENV{'GSDLHOME'},"perllib/plugins", 
					       "${pluginname}.pm");
	if (-e $colplugname) { require $colplugname; }
	elsif (-e $mainplugname) { require $mainplugname; }
	else {
	    gsprintf($outhandle, "{plugin.could_not_find_plugin}\n",
		     $pluginname);
	    die "\n";
	}

	# create a plugin object
	my ($plugobj);
	map { $_ = "\"$_\""; } @$pluginoptions;
	my $options = join (",", @$pluginoptions);
	if ($globals) {
	    if (@$pluginoptions) {
		$options .= ",";
	    }
	    $options .= "$globals";
	}
	$options =~ s/\$/\\\$/g;

	eval ("\$plugobj = new \$pluginname([],[$options])");
	die "$@" if $@;
	
	# initialize plugin
	$plugobj->init($verbosity, $outhandle, $failhandle);
	
	$plugobj->set_incremental($incremental);

	# add this object to the list
	push (@plugin_objects, $plugobj);
    }

    return \@plugin_objects;
}


sub begin {
    my ($pluginfo, $base_dir, $processor, $maxdocs, $gli) = @_;

    map { $_->{'gli'} = $gli; } @$pluginfo;
    map { $_->begin($pluginfo, $base_dir, $processor, $maxdocs); } @$pluginfo;
}


sub metadata_read {
    my ($pluginfo, $base_dir, $file, $metadata, $extrametakeys, $extrametadata, $processor, $maxdocs, $gli, $aux) = @_;

    $maxdocs = -1 unless defined $maxdocs && $maxdocs =~ /\d/;
    $gli = 0 unless defined $gli;

    my $rv = 0;
    my $glifile = $file;
    
    $glifile =~ s/^[\/\\]+//; # file sometimes starts with a / so get rid of it
    
    # Announce to GLI that we are handling a file
    print STDERR "<File n='$glifile'>\n" if $gli;
    
    # the .kill file is a handy (if not very elegant) way of aborting 
    # an import.pl or buildcol.pl process
    if (-e &util::filename_cat ($ENV{'GSDLCOLLECTDIR'}, ".kill")) {
	gsprintf($outhandle, "{plugin.kill_file}\n");
	die "\n";
    }

    my $had_error = 0;
    # pass this file by each of the plugins in turn until one
    # is found which will process it
    # read must return:
    # undef - could not recognise
    # -1 - tried but error
    # 0 - blocked
    # anything else for successful processing
	
    foreach my $plugobj (@$pluginfo) {

	$rv = $plugobj->metadata_read($pluginfo, $base_dir, $file, 
			     $metadata, $extrametakeys, $extrametadata, $processor, $maxdocs, $gli, $aux);

	if (defined $rv) {
	    if ($rv == -1) {
	        # an error has occurred
		$had_error = 1;
		print STDERR "<ProcessingError n='$glifile'>\n" if $gli;
	    } else {
        	return $rv;
	    }
	} # else undefined - was not recognised by the plugin
    }

    return 0;
}

sub read {
    my ($pluginfo, $base_dir, $file, $metadata, $processor, $maxdocs, $total_count, $gli, $aux) = @_;

    $maxdocs = -1 unless defined $maxdocs && $maxdocs =~ /\d/;
    $total_count = 0 unless defined $total_count && $total_count =~ /\d/;
    $gli = 0 unless defined $gli;

    my $rv = 0;
    my $glifile = $file;
    
    $glifile =~ s/^[\/\\]+//; # file sometimes starts with a / so get rid of it
    
    # Announce to GLI that we are handling a file
    print STDERR "<File n='$glifile'>\n" if $gli;
    
    # the .kill file is a handy (if not very elegant) way of aborting 
    # an import.pl or buildcol.pl process
    if (-e &util::filename_cat ($ENV{'GSDLCOLLECTDIR'}, ".kill")) {
	gsprintf($outhandle, "{plugin.kill_file}\n");
	die "\n";
    }

    my $had_error = 0;
    # pass this file by each of the plugins in turn until one
    # is found which will process it
    # read must return:
    # undef - could not recognise
    # -1 - tried but error
    # 0 - blocked
    # anything else for successful processing
	
    foreach my $plugobj (@$pluginfo) {

      	$rv = $plugobj->read($pluginfo, $base_dir, $file, 
			     $metadata, $processor, $maxdocs, $total_count, $gli, $aux);

	if (defined $rv) {
	    if ($rv == -1) {
	        # an error has occurred
		$had_error = 1;
	    } else {
        	return $rv;
	    }
	} # else undefined - was not recognised by the plugin
    }

    if ($had_error) {
	# was recognised but couldn't be processed
	if ($verbosity >= 2) {
	    gsprintf($outhandle, "{plugin.no_plugin_could_process}\n", $file);
	}
	# tell the GLI that it was not processed
	print STDERR "<NonProcessedFile n='$glifile'>\n" if $gli;
      
	gsprintf($failhandle, "$file: {plugin.no_plugin_could_process_this_file}\n");
	$stats->{'num_not_processed'} ++;
    } else {
	# was not recognised
	if ($verbosity >= 2) {
	    gsprintf($outhandle, "{plugin.no_plugin_could_recognise}\n",$file);
	}
	# tell the GLI that it was not processed
	print STDERR "<NonRecognisedFile n='$glifile'>\n" if $gli;
	
	gsprintf($failhandle, "$file: {plugin.no_plugin_could_recognise_this_file}\n");
	$stats->{'num_not_recognised'} ++;
    }
    return 0;
}

# write out some general stats that the plugins have compiled - note that
# the buildcol.pl process doesn't currently call this process so the stats
# are only output after import.pl -
sub write_stats {
    my ($pluginfo, $statshandle, $faillog, $gli) = @_;

    $gli = 0 unless defined $gli;

    foreach my $plugobj (@$pluginfo) {
	$plugobj->compile_stats($stats);
    }

    my $total = $stats->{'num_processed'} + $stats->{'num_blocked'} + 
	$stats->{'num_not_processed'} + $stats->{'num_not_recognised'};

    print STDERR "<ImportComplete considered='$total' processed='$stats->{'num_processed'}' blocked='$stats->{'num_blocked'}' ignored='$stats->{'num_not_recognised'}' failed='$stats->{'num_not_processed'}'>\n" if $gli;

    if ($total == 1) {
	gsprintf($statshandle, "* {plugin.one_considered}\n");
    } else {
	gsprintf($statshandle, "* {plugin.n_considered}\n", $total);
    }
    if ($stats->{'num_archives'}) {
	if ($stats->{'num_archives'} == 1) {
	    gsprintf($statshandle, "   ({plugin.including_archive})\n");
	}
	else {
	    gsprintf($statshandle, "   ({plugin.including_archives})\n",
		     $stats->{'num_archives'});
	}
    }
    if ($stats->{'num_processed'} == 1) {
	gsprintf($statshandle, "* {plugin.one_included}\n");
    } else {
	gsprintf($statshandle, "* {plugin.n_included}\n", $stats->{'num_processed'});
    }
    if ($stats->{'num_not_recognised'}) {
	if ($stats->{'num_not_recognised'} == 1) {
	    gsprintf($statshandle, "* {plugin.one_unrecognised}\n");
	} else {
	    gsprintf($statshandle, "* {plugin.n_unrecognised}\n",
		     $stats->{'num_not_recognised'});
	}

    }
    if ($stats->{'num_not_processed'}) {
	if ($stats->{'num_not_processed'} == 1) {
	    gsprintf($statshandle, "* {plugin.one_rejected}\n");
	} else {
	    gsprintf($statshandle, "* {plugin.n_rejected}\n",
		     $stats->{'num_not_processed'});
	}
    }
    if ($stats->{'num_not_processed'} || $stats->{'num_not_recognised'}) {
	gsprintf($statshandle, " {plugin.see_faillog}\n", $faillog);
    }
}

sub end {
    my ($pluginfo, $processor) = @_;
    map { $_->end($processor); } @$pluginfo;
}

sub deinit {
    my ($pluginfo, $processor) = @_;
   

    map { $_->deinit($processor); } @$pluginfo;
}

1;