# MGBuilder object
#

package mgbuilder;

use cfgread;
use colcfg;
use plugin;
use util;

$maxdocsize = 12000;

%wanted_index_files = ('td'=>1,
		       't'=>1,
		       'idb'=>1,
		       'ib1'=>1,
		       'ib2'=>1,
		       'ib3'=>1,
		       'i'=>1,
		       'ip'=>1,
		       'tiw'=>1,
		       'wa'=>1);


sub new {
    my ($class, $collection, $source_dir, $build_dir, $verbosity) = @_;

    # create an mgbuilder object
    my $self = bless {'collection'=>$collection,
		      'source_dir'=>$source_dir,
		      'build_dir'=>$build_dir,
		      'verbosity'=>$verbosity}, $class;


    # read in the collection configuration file
    if (!-e "$ENV{'GSDLHOME'}/collect/$collection/collect.cfg") {
	die "mgbuilder::new - couldn't find collect.cfg for collection $collection\n";
    }
    $self->{'collect_cfg'} = &colcfg::read_collect_cfg ("$ENV{'GSDLHOME'}/collect/" .
							"$collection/collect.cfg");


    # sort out subcollection indexes
    if (defined $self->{'collect_cfg'}->{'indexsubcollections'}) {
	my $indexes = $self->{'collect_cfg'}->{'indexes'};
	$self->{'collect_cfg'}->{'indexes'} = [];
	foreach $subcollection (@{$self->{'collect_cfg'}->{'indexsubcollections'}}) {
	    foreach $index (@$indexes) {
		push (@{$self->{'collect_cfg'}->{'indexes'}}, "$index:$subcollection");
	    }
	}
    }

    # get the list of plugins for this collection
    my @plugins = (); # some good choice of plugins .... ????
    if (defined $self->{'collect_cfg'}->{'plugins'}) {
	@plugins = @{$self->{'collect_cfg'}->{'plugins'}};
    }
    

    # load all the plugins
    $self->{'pluginfo'} = &plugin::load_plugins ($collection, \@plugins);
    if (scalar(@{$self->{'pluginfo'}}) == 0) {
	print STDERR "No plugins were loaded.\n";
	die "\n";
    }
    

    # load up the document processor for building
    # if a buildproc class has been created for this collection, use it
    # otherwise, use the mg buildproc
    my ($buildprocdir, $buildproctype);
    if (-e "$ENV{'GSDLHOME'}/collect/$collection/perllib/${collection}buildproc.pm") {
	$buildprocdir = "$ENV{'GSDLHOME'}/collect/$collection/perllib";
	$buildproctype = "${collection}buildproc";
    } else {
	$buildprocdir = "$ENV{'GSDLHOME'}/perllib";
	$buildproctype = "mgbuildproc";
    }
    require "$buildprocdir/$buildproctype.pm";

    eval("\$self->{'buildproc'} = new $buildproctype(\$collection, " .
	 "\$source_dir, \$build_dir, \$verbosity)");
    die "$@" if $@;


    return $self;
}

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

    # remove any old builds
    &util::rm_r($self->{'build_dir'});
    &util::mk_all_dir($self->{'build_dir'});
        
    # make the text directory
    my $textdir = "$self->{'build_dir'}/text";
    &util::mk_all_dir($textdir);
}

sub compress_text {
    my $self = shift (@_);
    my $exedir = "$ENV{'GSDLHOME'}/bin/$ENV{'GSDLOS'}";
    my $exe = &util::get_os_exe ();

    &util::mk_all_dir (&util::filename_cat($self->{'build_dir'}, "text"));
    my $basefilename = "text/$self->{'collection'}";
    my $fulltextprefix = &util::filename_cat ($self->{'build_dir'}, $basefilename);

    my $osextra = "";
    if ($ENV{'GSDLOS'} =~ /^windows$/i) {
	$fulltextprefix =~ s/\//\\/g;
    } else {
	$osextra = " -d /";
    }

    print STDERR "\n*** creating the compressed text\n" if ($self->{'verbosity'} >= 1);

    # set up the document processor
    $self->{'buildproc'}->set_output_handle ('mgbuilder::PIPEOUT');
    $self->{'buildproc'}->set_mode ('text');
    $self->{'buildproc'}->set_index ('section:text');
    
    # collect the statistics for the text
    # -b $maxdocsize sets the maximum document size to be 12 meg
    print STDERR "\n    collecting text statistics\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_passes$exe" || !open (PIPEOUT, 
            "| $exedir/mg_passes$exe -f $fulltextprefix -b $maxdocsize -T1 $osextra")) {
	die "mgbuilder::compress_text - couldn't run $exedir/mg_passes$exe\n";
    }
    $self->{'buildproc'}->reset();
    &plugin::read ($self->{'pluginfo'}, $self->{'source_dir'}, 
		   "", {}, $self->{'buildproc'});
    close (PIPEOUT);

    # create the compression dictionary
    # the compression dictionary is built by assuming the stats are from a seed
    # dictionary (-S), if a novel word is encountered it is spelled out (-H),
    # and the resulting dictionary must be less than 5 meg with the most frequent
    # words being put into the dictionary first (-2 -k 5120)
    print STDERR "\n    creating the compression dictionary\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_compression_dict$exe") {
	die "mgbuilder::compress_text - couldn't run $exedir/mg_compression_dict$exe\n";
    }
    system ("$exedir/mg_compression_dict$exe -f $fulltextprefix -S -H -2 -k 5120 $osextra");

    # compress the text
    # -b $maxdocsize sets the maximum document size to be 12 meg
    print STDERR "\n    compressing the text\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_passes$exe" || !open (PIPEOUT, 
            "| $exedir/mg_passes$exe -f $fulltextprefix -b $maxdocsize -T2 $osextra")) {
	die "mgbuilder::compress_text - couldn't run $exedir/mg_passes$exe\n";
    }
    $self->{'buildproc'}->reset();
    &plugin::read ($self->{'pluginfo'}, $self->{'source_dir'}, 
		   "", {}, $self->{'buildproc'});
    close (PIPEOUT);
}

sub build_indexes {
    my $self = shift (@_);
    my $indexes = $self->{'collect_cfg'}->{'indexes'};

    # create the mapping between the index descriptions 
    # and their directory names
    $self->{'index_mapping'} = $self->create_index_mapping ($indexes);

    # build each of the indexes
    foreach $index (@$indexes) {
	print STDERR "\n*** building index $index in subdirectory " . 
	    "$self->{'index_mapping'}->{$index}\n" if ($self->{'verbosity'} >= 1);
	$self->build_index($index);
    }
}

# creates directory names for each of the index descriptions
sub create_index_mapping {
    my $self = shift (@_);
    my ($indexes) = @_;

    my %mapping = ();
    
    # dirnames is used to check for collisions. Start this off
    # with the manditory directory names
    my %dirnames = ('text'=>'text',
		    'extra'=>'extra');
    
    foreach $index (@$indexes) {
	my ($level, $fields, $subcollection) = split (":", $index);
	my @fields = split (/,/, $fields);
	splice (@fields, 2); # just want first two fields
	
	# the directory names starts with the first character of the index level
	my ($dirname) = $level =~ /^(.)/;

	# next comes a processed version of the first two fields in the index
	# the processed version contains the first character and the next
	# consonant
	map {s/^(.).*?([bcdfghjklmnpqrstvwxyz]).*$/$1$2/i;} @fields;
	$dirname .= join("", @fields);

	# next comes a processed version of the subcollection if there is one.
	# the processed version contains the first character and the next
	# consonant if there's only one field, otherwise the first character
	# of the first two fields
	if (defined ($subcollection) && $subcollection =~ /\w/) {
	    @fields = split /,/, $subcollection;
	    if (scalar @fields >= 2) {
		splice (@fields, 2);
		map {s/^(.).*$/$1/i;} @fields;
		$dirname .= join("", @fields);
	    } else {
		$subcollection =~ s/^(.).*?([bcdfghjklmnpqrstvwxyz]?).*$/$1$2/i;
		$dirname .= $subcollection;
	    }
	}

	# convert the directory name to lowercase
	$dirname = lc ($dirname);

	# add a number to make this directory name unique
	if (defined $dirnames{$dirname}) {
	    my $num = 1;
	    while (defined $dirnames{"$dirname$num"}) {
		$num++;
	    }
	    $dirname .= $num;
	}
	
	$mapping{$index} = $dirname;
	$dirnames{$dirname} = $index;
    }

    return \%mapping;
}


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

    # get the full index directory path and make sure it exists
    my $indexdir = $self->{'index_mapping'}->{$index};
    &util::mk_all_dir (&util::filename_cat($self->{'build_dir'}, $indexdir));
    my $fullindexprefix = &util::filename_cat ($self->{'build_dir'}, $indexdir, 
					       $self->{'collection'});
    my $fulltextprefix = &util::filename_cat ($self->{'build_dir'}, "text", 
					       $self->{'collection'});

    # get any os specific stuff
    my $exedir = "$ENV{'GSDLHOME'}/bin/$ENV{'GSDLOS'}";
    my $exe = &util::get_os_exe ();
    my $osextra = "";
    if ($ENV{'GSDLOS'} =~ /^windows$/i) {
	$fullindexprefix =~ s/\//\\/g;
    } else {
	$osextra = " -d /";
    }

    # get the index level from the index description
    # the index will be level 2 unless we are building a
    # paragraph level index
    my $index_level = 2;
    $index_level = 3 if $index =~ /^paragraph/i;

    # get the index expression if this index belongs
    # to a subcollection
    my $indexexparr = [];
    my ($level, $fields, $subcollection) = split (":", $index);
    my (@subcollections) = split /,/, $subcollection;

    foreach $subcollection (@subcollections) {
	if (defined ($self->{'collect_cfg'}->{'subcollection'}->{$subcollection})) {
	    push (@$indexexparr, $self->{'collect_cfg'}->{'subcollection'}->{$subcollection});
	} 
    }
    
    # set up the document processor
    $self->{'buildproc'}->set_output_handle ('mgbuilder::PIPEOUT');
    $self->{'buildproc'}->set_mode ('text');
    $self->{'buildproc'}->set_index ($index, $indexexparr);


    # Build index dictionary. Uses verbatim stem method
    print STDERR "\n    creating index dictionary\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_passes$exe" || !open (PIPEOUT, 
	    "| $exedir/mg_passes$exe -f $fullindexprefix -b $maxdocsize " .
	    "-$index_level -m 32 -s 0 -G -t 10 -N1 $osextra")) {
	die "mgbuilder::build_index - couldn't run $exedir/mg_passes$exe\n";
    }
    $self->{'buildproc'}->reset();
    &plugin::read ($self->{'pluginfo'}, $self->{'source_dir'}, 
		   "", {}, $self->{'buildproc'});
    close (PIPEOUT);

    # create the perfect hash function
    if (!-e "$exedir/mg_perf_hash_build$exe") {
	die "mgbuilder::build_index - couldn't run $exedir/mg_perf_hash_build$exe\n";
    }
    system ("$exedir/mg_perf_hash_build$exe -f $fullindexprefix $osextra");

    # invert the text
    print STDERR "\n    inverting the text\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_passes$exe" || !open (PIPEOUT, 
	    "| $exedir/mg_passes$exe -f $fullindexprefix -b $maxdocsize " .
	    "-$index_level -c 3 -G -t 10 -N2 $osextra")) {
	die "mgbuilder::build_index - couldn't run $exedir/mg_passes$exe\n";
    }
    $self->{'buildproc'}->reset();
    &plugin::read ($self->{'pluginfo'}, $self->{'source_dir'}, 
		   "", {}, $self->{'buildproc'});
    close (PIPEOUT);

    # create the weights file
    print STDERR "\n    create the weights file\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_weights_build$exe") {
	die "mgbuilder::build_index - couldn't run $exedir/mg_weights_build$exe\n";
    }
    system ("$exedir/mg_weights_build$exe -f $fullindexprefix -t $fulltextprefix $osextra");

    # create 'on-disk' stemmed dictionary
    print STDERR "\n    creating 'on-disk' stemmed dictionary\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_invf_dict$exe") {
	die "mgbuilder::build_index - couldn't run $exedir/mg_invf_dict$exe\n";
    }
    system ("$exedir/mg_invf_dict$exe -f $fullindexprefix $osextra");


    # creates stem index files for the various stemming methods
    print STDERR "\n    creating stem indexes\n"  if ($self->{'verbosity'} >= 1);
    if (!-e "$exedir/mg_stem_idx$exe") {
	die "mgbuilder::build_index - couldn't run $exedir/mg_stem_idx$exe\n";
    }
    system ("$exedir/mg_stem_idx$exe -b 4096 -s1 -f $fullindexprefix $osextra");
    system ("$exedir/mg_stem_idx$exe -b 4096 -s2 -f $fullindexprefix $osextra");
    system ("$exedir/mg_stem_idx$exe -b 4096 -s3 -f $fullindexprefix $osextra");

    
    # remove unwanted files
    my $tmpdir = &util::filename_cat ($self->{'build_dir'}, $indexdir);
    opendir (DIR, $tmpdir) || die
	"mgbuilder::build_index - couldn't read directory $tmpdir\n";
    foreach $file (readdir(DIR)) {
	next if $file =~ /^\./;
	my ($suffix) = $file =~ /\.([^\.]+)$/;
	if (defined $suffix && !defined $wanted_index_files{$suffix}) {
	    # delete it!
#	    print STDERR "deleting $file\n";
	    &util::rm (&util::filename_cat ($tmpdir, $file));
	}
    }
    closedir (DIR);
}

sub make_infodatabase {
    my $self = shift (@_);
    my $textdir = &util::filename_cat($self->{'build_dir'}, "text");
    &util::mk_all_dir ($textdir);

    # assume little-endian for now :-)
    my $fulldbname = &util::filename_cat ($textdir, "$self->{'collection'}.ldb");
    $fulldbname =~ s/\//\\/g if ($ENV{'GSDLOS'} =~ /^windows$/i);
    my $exedir = "$ENV{'GSDLHOME'}/bin/$ENV{'GSDLOS'}";
    my $exe = &util::get_os_exe ();

    print STDERR "\n*** creating the info database\n" if ($self->{'verbosity'} >= 1);

    # set up the document processor
    $self->{'buildproc'}->set_output_handle ('mgbuilder::PIPEOUT');
    $self->{'buildproc'}->set_mode ('infodb');
    
    # collect the statistics for the text
    # -b $maxdocsize sets the maximum document size to be 12 meg
    if (!-e "$exedir/txt2db$exe" || !open (PIPEOUT, 
            "| $exedir/txt2db$exe $fulldbname")) {
	die "mgbuilder::make_infodatabase - couldn't run $exedir/txt2db$exe\n";
    }
    $self->{'buildproc'}->reset();
    &plugin::read ($self->{'pluginfo'}, $self->{'source_dir'}, 
		   "", {}, $self->{'buildproc'});
    close (PIPEOUT);
}

sub make_auxiliary_files {
    my $self = shift (@_);
    my ($index);
    my %build_cfg = ();

    print STDERR "\n*** creating auxiliary files \n" if ($self->{'verbosity'} >= 1);

    # get the text directory
    &util::mk_all_dir ($self->{'build_dir'});

    # store the build date
    $build_cfg->{'builddate'} = time;

    # store the number of documents and number of bytes
    $build_cfg->{'numdocs'} = $self->{'buildproc'}->get_num_docs();
    $build_cfg->{'numbytes'} = $self->{'buildproc'}->get_num_bytes();

    # store the mapping between the index names and the directory names
    my @indexmap = ();
    foreach $index (@{$self->{'collect_cfg'}->{'indexes'}}) {
	push (@indexmap, "$index\-\>$self->{'index_mapping'}->{$index}");
    }
    $build_cfg->{'indexmap'} = \@indexmap;

    # write out the build information
    &cfgread::write_cfg_file("$self->{'build_dir'}/build.cfg", $build_cfg,
			     '^(builddate|numdocs|numbytes)$', '^(indexmap)$');

}

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


1;