###########################################################################
#
# util.pm -- various useful utilities
# 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 util;

use File::Copy;
use File::Basename;


# removes files (but not directories)
sub rm {
    my (@files) = @_;
    my @filefiles = ();

    # make sure the files we want to delete exist 
    # and are regular files
    foreach $file (@files) {
	if (!-e $file) {
	    print STDERR "util::rm $file does not exist\n";
	} elsif ((!-f $file) && (!-l $file)) {
	    print STDERR "util::rm $file is not a regular (or symbolic) file\n";
	} else {
	    push (@filefiles, $file);
	}
    }
    
    # remove the files
    my $numremoved = unlink @filefiles;

    # check to make sure all of them were removed
    if ($numremoved != scalar(@filefiles)) {
	print STDERR "util::rm Not all files were removed\n";
    }
}


# recursive removal
sub rm_r {
    my (@files) = @_;

    # recursively remove the files
    foreach $file (@files) {
	$file =~ s/[\/\\]+$//; # remove trailing slashes
	
	if (!-e $file) {
	    print STDERR "util::rm_r $file does not exist\n";

	} elsif ((-d $file) && (!-l $file)) { # don't recurse down symbolic link
	    # get the contents of this directory
	    if (!opendir (INDIR, $file)) {
		print STDERR "util::rm_r could not open directory $file\n";
	    } else {
		my @filedir = grep (!/^\.\.?$/, readdir (INDIR));
		closedir (INDIR);

		# remove all the files in this directory
		&rm_r (map {$_="$file/$_";} @filedir);

		# remove this directory
		if (!rmdir $file) {
		    print STDERR "util::rm_r couldn't remove directory $file\n";
		}
	    }

	} else {
	    # remove this file
	    &rm ($file);
	}
    }
}

# moves a file or a group of files
sub mv {
    my $dest = pop (@_);
    my (@srcfiles) = @_;

    # remove trailing slashes from source and destination files
    $dest =~ s/[\\\/]+$//;
    map {$_ =~ s/[\\\/]+$//;} @srcfiles;

    # a few sanity checks
    if (scalar (@srcfiles) == 0) {
	print STDERR "util::mv no destination directory given\n";
	return;
    } elsif ((scalar (@srcfiles) > 1) && (!-d $dest)) {
	print STDERR "util::mv if multiple source files are given the ".
	    "destination must be a directory\n";
	return;
    }

    # move the files
    foreach $file (@srcfiles) {
	my $tempdest = $dest;
	if (-d $tempdest) {
	    my ($filename) = $file =~ /([^\\\/]+)$/;
	    $tempdest .= "/$filename";
	}
	if (!-e $file) {
	    print STDERR "util::mv $file does not exist\n";
	} else {
	    rename ($file, $tempdest);
	}
    }
}


# copies a file or a group of files
sub cp {
    my $dest = pop (@_);
    my (@srcfiles) = @_;

    # remove trailing slashes from source and destination files
    $dest =~ s/[\\\/]+$//;
    map {$_ =~ s/[\\\/]+$//;} @srcfiles;

    # a few sanity checks
    if (scalar (@srcfiles) == 0) {
	print STDERR "util::cp no destination directory given\n";
	return;
    } elsif ((scalar (@srcfiles) > 1) && (!-d $dest)) {
	print STDERR "util::cp if multiple source files are given the ".
	    "destination must be a directory\n";
	return;
    }

    # copy the files
    foreach $file (@srcfiles) {
	my $tempdest = $dest;
	if (-d $tempdest) {
	    my ($filename) = $file =~ /([^\\\/]+)$/;
	    $tempdest .= "/$filename";
	}
	if (!-e $file) {
	    print STDERR "util::cp $file does not exist\n";
	} elsif (!-f $file) {
	    print STDERR "util::cp $file is not a plain file\n";
	} else {
	    &File::Copy::copy ($file, $tempdest);
	}
    }
}



# recursively copies a file or group of files
# syntax: cp_r (sourcefiles, destination directory)
# destination must be a directory - to copy one file to
# another use cp instead
sub cp_r {
    my $dest = pop (@_);
    my (@srcfiles) = @_;

    # a few sanity checks
    if (scalar (@srcfiles) == 0) {
	print STDERR "util::cp_r no destination directory given\n";
	return;
    } elsif (-f $dest) {
	print STDERR "util::cp_r destination must be a directory\n";
	return;
    }
    
    # create destination directory if it doesn't exist already
    if (! -d $dest) {
	my $store_umask = umask(0002);
	mkdir ($dest, 0777);
	umask($store_umask);
    } 

    # copy the files
    foreach $file (@srcfiles) {

	if (!-e $file) {
	    print STDERR "util::cp_r $file does not exist\n";

	} elsif (-d $file) {
	    # make the new directory
	    my ($filename) = $file =~ /([^\\\/]*)$/;
	    $dest = &util::filename_cat ($dest, $filename);
	    my $store_umask = umask(0002);
	    mkdir ($dest, 0777);
	    umask($store_umask);

	    # get the contents of this directory
	    if (!opendir (INDIR, $file)) {
		print STDERR "util::cp_r could not open directory $file\n";
	    } else {
		my @filedir = readdir (INDIR);
		closedir (INDIR);
		foreach $f (@filedir) {
		    next if $f =~ /^\.\.?$/;
		    # copy all the files in this directory
		    my $ff = &util::filename_cat ($file, $f); 
		    &cp_r ($ff, $dest);
		}
	    }

	} else {
	    &cp($file, $dest);
	}
    }
}


sub mk_dir {
    my ($dir) = @_;

    my $store_umask = umask(0002);
    my $mkdir_ok = mkdir ($dir, 0777);
    umask($store_umask);
    
    if (!$mkdir_ok) 
    {
	print STDERR "util::mk_dir could not create directory $dir\n";
	return;
    }
}

# in case anyone cares - I did some testing (using perls Benchmark module)
# on this subroutine against File::Path::mkpath (). mk_all_dir() is apparently
# slightly faster (surprisingly) - Stefan.
sub mk_all_dir {
    my ($dir) = @_;

    # use / for the directory separator, remove duplicate and
    # trailing slashes
    $dir=~s/[\\\/]+/\//g; 
    $dir=~s/[\\\/]+$//;

    # make sure the cache directory exists
    my $dirsofar = "";
    my $first = 1;
    foreach $dirname (split ("/", $dir)) {
	$dirsofar .= "/" unless $first;
	$first = 0;

	$dirsofar .= $dirname;

	next if $dirname =~ /^(|[a-z]:)$/i;
	if (!-e $dirsofar)
	    {
		my $store_umask = umask(0002);
		my $mkdir_ok = mkdir ($dirsofar, 0777);
		umask($store_umask);
		if (!$mkdir_ok)
		{
		    print STDERR "util::mk_all_dir could not create directory $dirsofar\n";
		    return;
		}
	    }
    }
}

# make hard link to file if supported by OS, otherwise copy the file
sub hard_link {
    my ($src, $dest) = @_;

    # remove trailing slashes from source and destination files
    $src =~ s/[\\\/]+$//;
    $dest =~ s/[\\\/]+$//;

    # a few sanity checks
    if (-e $dest) {
	# destination file already exists
	return;
    }
    elsif (!-e $src) {
	print STDERR "util::hard_link source file $src does not exist\n";
	return;
    }
    elsif (-d $src) {
	print STDERR "util::hard_link source $src is a directory\n";
	return;
    }

    my $dest_dir = &File::Basename::dirname($dest);
    mk_all_dir($dest_dir) if (!-e $dest_dir);

    # link not supported on wondows
    if ($ENV{'GSDLOS'} =~ /^windows$/i) {
	&File::Copy::copy ($src, $dest);

    } elsif (!link($src, $dest)) {
	print STDERR "util::hard_link: unable to create hard link. ";
	print STDERR " Attempting to copy file: $src -> $dest\n";
	&File::Copy::copy ($src, $dest);
    }
}

# make soft link to file if supported by OS, otherwise return error
sub soft_link {
    my ($src, $dest) = @_;

    # remove trailing slashes from source and destination files
    $src =~ s/[\\\/]+$//;
    $dest =~ s/[\\\/]+$//;

    # a few sanity checks
    if (!-e $src) {
	print STDERR "util::soft_link source file $src does not exist\n";
	return 0;
    }

    my $dest_dir = &File::Basename::dirname($dest);
    mk_all_dir($dest_dir) if (!-e $dest_dir);

    if (!symlink($src, $dest))
    {
	print STDERR "util::soft_link: unable to create soft link.";
	return 0;
    }

    return 1;
}




# updates a copy of a directory in some other part of the filesystem
# verbosity settings are: 0=low, 1=normal, 2=high
# both $fromdir and $todir should be absolute paths
sub cachedir {
    my ($fromdir, $todir, $verbosity) = @_;
    $verbosity = 1 unless defined $verbosity;

    # use / for the directory separator, remove duplicate and
    # trailing slashes
    $fromdir=~s/[\\\/]+/\//g; 
    $fromdir=~s/[\\\/]+$//;
    $todir=~s/[\\\/]+/\//g; 
    $todir=~s/[\\\/]+$//;

    &mk_all_dir ($todir);

    # get the directories in ascending order
    if (!opendir (FROMDIR, $fromdir)) {
	print STDERR "util::cachedir could not read directory $fromdir\n";
	return;
    }
    my @fromdir = grep (!/^\.\.?$/, sort(readdir (FROMDIR)));
    closedir (FROMDIR);

    if (!opendir (TODIR, $todir)) {
	print STDERR "util::cacedir could not read directory $todir\n";
	return;
    }
    my @todir = grep (!/^\.\.?$/, sort(readdir (TODIR)));
    closedir (TODIR);

    my $fromi = 0;
    my $toi = 0;
		    
    while ($fromi < scalar(@fromdir) || $toi < scalar(@todir)) {
#	print "fromi: $fromi toi: $toi\n";

	# see if we should delete a file/directory
	# this should happen if the file/directory
	# is not in the from list or if its a different
	# size, or has an older timestamp
	if ($toi < scalar(@todir)) {
	    if (($fromi >= scalar(@fromdir)) ||
		($todir[$toi] lt $fromdir[$fromi] || 
		 ($todir[$toi] eq $fromdir[$fromi] && 
		  &differentfiles("$fromdir/$fromdir[$fromi]","$todir/$todir[$toi]",
				  $verbosity)))) {

		# the files are different
		&rm_r("$todir/$todir[$toi]");
		splice(@todir, $toi, 1); # $toi stays the same

	    } elsif ($todir[$toi] eq $fromdir[$fromi]) {
		# the files are the same
		# if it is a directory, check its contents
		if (-d "$todir/$todir[$toi]") {
		    &cachedir ("$fromdir/$fromdir[$fromi]",
			       "$todir/$todir[$toi]", $verbosity);
		}

		$toi++;
		$fromi++;
		next;
	    }
	}
  
	# see if we should insert a file/directory
	# we should insert a file/directory if there
	# is no tofiles left or if the tofile does not exist
	if ($fromi < scalar(@fromdir) && ($toi >= scalar(@todir) || 
					  $todir[$toi] gt $fromdir[$fromi])) {
	    &cp_r ("$fromdir/$fromdir[$fromi]", "$todir/$fromdir[$fromi]");
	    splice (@todir, $toi, 0, $fromdir[$fromi]);

	    $toi++;
	    $fromi++;
	}
    }
}

# this function returns -1 if either file is not found
# assumes that $file1 and $file2 are absolute file names or
# in the current directory
# $file2 is allowed to be newer than $file1
sub differentfiles {
    my ($file1, $file2, $verbosity) = @_;
    $verbosity = 1 unless defined $verbosity;

    $file1 =~ s/\/+$//;
    $file2 =~ s/\/+$//;
    
    my ($file1name) = $file1 =~ /\/([^\/]*)$/;
    my ($file2name) = $file2 =~ /\/([^\/]*)$/;

    return -1 unless (-e $file1 && -e $file2);
    if ($file1name ne $file2name) {
	print STDERR "filenames are not the same\n" if ($verbosity >= 2);
	return 1;
    }

    @file1stat = stat ($file1);
    @file2stat = stat ($file2);

    if (-d $file1) {
	if (! -d $file2) {
	    print STDERR "one file is a directory\n" if ($verbosity >= 2);
	    return 1;
	}
	return 0;
    }

    # both must be regular files
    unless (-f $file1 && -f $file2) {
	print STDERR "one file is not a regular file\n" if ($verbosity >= 2);
	return 1;
    }

    # the size of the files must be the same
    if ($file1stat[7] != $file2stat[7]) {
	print STDERR "different sized files\n" if ($verbosity >= 2);
	return 1;
    }

    # the second file cannot be older than the first
    if ($file1stat[9] > $file2stat[9]) {
	print STDERR "file is older\n" if ($verbosity >= 2);
	return 1;
    }

    return 0;
}


sub get_tmp_filename {
    my $tmpdir = "$ENV{'GSDLHOME'}/tmp";
    &mk_all_dir ($tmpdir) unless -e $tmpdir;

    my $count = 1000;
    my $rand = int(rand $count);
    while (-e "$tmpdir/F$rand") {
	$rand = int(rand $count);
	$count++;
    }

    return "$tmpdir/F$rand";
}


sub filename_cat {
    my (@filenames) = @_;
    my $filename = join("/", @filenames);

    # remove duplicate slashes and remove the last slash
    if ($ENV{'GSDLOS'} =~ /^windows$/i) {
	$filename =~ s/[\\\/]+/\\/g;
    } else {
	$filename =~ s/[\/]+/\//g; 
	# DB: want a filename abc\de.html to remain like this
    }
    $filename =~ s/[\\\/]$//;

    return $filename;
}

# returns 1 if filename1 and filename2 point to the same
# file or directory
sub filenames_equal {
    my ($filename1, $filename2) = @_;

    # use filename_cat to clean up trailing slashes and 
    # multiple slashes
    $filename1 = filename_cat ($filename1);
    $filename1 = filename_cat ($filename1);

    # filenames not case sensitive on windows
    if ($ENV{'GSDLOS'} =~ /^windows$/i) {
	$filename1 =~ tr/[A-Z]/[a-z]/;
	$filename2 =~ tr/[A-Z]/[a-z]/;
    }
    return 1 if $filename1 eq $filename2;
    return 0;
}

sub get_os_dirsep {

    if ($ENV{'GSDLOS'} =~ /^windows$/i) {
	return "\\\\";
    } else {
	return "\\\/";
    }
}

sub get_re_dirsep {

    return "\\\\|\\\/";
}


# if this is running on windows we want binaries to end in
# .exe, otherwise they don't have to end in any extension
sub get_os_exe {
    return ".exe" if $ENV{'GSDLOS'} =~ /^windows$/i;
    return "";
}


# test to see whether this is a big or little endian machine
sub is_little_endian {
    return (ord(substr(pack("s",1), 0, 1)) == 1);
}


# will return the collection name if successful, "" otherwise
sub use_collection {
    my ($collection, $collectdir) = @_;

    if (!defined $collectdir || $collectdir eq "") {
	$collectdir = &filename_cat ($ENV{'GSDLHOME'}, "collect");
    }

    # get and check the collection
    if (!defined($collection) || $collection eq "") {
	if (defined $ENV{'GSDLCOLLECTION'}) {
	    $collection = $ENV{'GSDLCOLLECTION'};
	} else {
	    print STDERR "No collection specified\n";
	    return "";
	}
    }
    
    if ($collection eq "modelcol") {
	print STDERR "You can't use modelcol.\n";
	return "";
    }

    # make sure the environment variables GSDLCOLLECTION and GSDLCOLLECTDIR
    # are defined
    $ENV{'GSDLCOLLECTION'} = $collection unless defined $ENV{'GSDLCOLLECTION'};
    $ENV{'GSDLCOLLECTDIR'} = &filename_cat ($collectdir, $collection);

    # make sure this collection exists
    if (!-e $ENV{'GSDLCOLLECTDIR'}) {
	print STDERR "Invalid collection ($collection).\n";
	return "";
    }

    # everything is ready to go
    return $collection;
}

1;
