#!/usr/bin/perl

=head1 NAME

vidir - edit directory

=head1 SYNOPSIS

B<vidir> [--verbose] [directory|file|-] ...

=head1 DESCRIPTION

vidir allows editing of the contents of a directory in a text editor. If no
directory is specified, the current directory is edited. 

When editing a directory, each item in the directory will appear on its own
numbered line. These numbers are how vidir keeps track of what items are
changed. Delete lines to remove files from the directory, or
edit filenames to rename files. You can also switch pairs of numbers to
swap filenames.

Note that if "-" is specified as the directory to edit, it reads a list of
filenames from stdin and displays those for editing. Alternatively, a list
of files can be specified on the command line.

=head1 OPTIONS

=over 4

=item -v, --verbose

Verbosely display the actions taken by the program.

=back

=head1 EXAMPLES

=over 4

=item vidir

=item vidir *.jpeg

Typical uses.

=item find | vidir -

Edit subdirectory contents too. To delete subdirectories,
delete all their contents and the subdirectory itself in the editor.

=item find -type f | vidir -

Edit all files under the current directory and subdirectories.

=head1 ENVIRONMENT VARIABLES

=over 4

=item EDITOR

Editor to use.

=item VISUAL

Also supported to determine what editor to use.

=back

=head1 AUTHOR

Copyright 2006 by Joey Hess <joey@kitenet.net>

Licensed under the GNU GPL.

=cut

use File::Spec;
use File::Temp;
use Getopt::Long;

my $error=0;

my $verbose=0;
if (! GetOptions("verbose|v" => \$verbose)) {
	die "Usage: $0 [--verbose] [directory|file|-]\n";
}

my @dir;
if (! @ARGV) {
	push @ARGV, "."
}
foreach my $item (@ARGV) {
	if ($item eq "-") {
		push @dir, map { chomp; $_ } <STDIN>;
		close STDIN;
		open(STDIN, "/dev/tty") || die "reopen: $!\n";
	}
	elsif (-d $item) {
		$item =~ s{/?$}{/};
		opendir(DIR, $item) || die "$0: cannot read $item: $!\n";
		push @dir, map { "$item$_" } sort readdir(DIR);
		closedir DIR;
	}
	else {
		push @dir, $item;
	}
}

if (grep(/[[:cntrl:]]/, @dir)) {
	die "$0: control characters in filenames are not supported\n";
}

my $tmp=File::Temp->new(TEMPLATE => "dirXXXXX", DIR => File::Spec->tmpdir);
open (OUT, ">".$tmp->filename) || die "$0: cannot create ".$tmp->filename.": $!\n";

my %item;
my $c=0;
foreach (@dir) {
	next if /^(.*\/)?\.$/ || /^(.*\/)?\.\.$/;
	$item{++$c}=$_;
	print OUT "$c\t$_\n";
}
@dir=();
close OUT || die "$0: cannot write ".$tmp->filename.": $!\n";

my @editor="vi";
if (-x "/usr/bin/editor") {
	@editor="/usr/bin/editor";
}
if (exists $ENV{EDITOR}) {
	@editor=split(' ', $ENV{EDITOR});
}
if (exists $ENV{VISUAL}) {
	@editor=split(' ', $ENV{VISUAL});
}
$ret=system(@editor, $tmp);
if ($ret != 0) {
	die "@editor exited nonzero, aborting\n";
}

open (IN, $tmp->filename) || die "$0: cannot read ".$tmp->filename.": $!\n";
while (<IN>) {
	chomp;
	if (/^(\d+)\t{0,1}(.*)/) {
		my $num=int($1);
		my $name=$2;
		if (! exists $item{$num}) {
			die "$0: unknown item number $num\n";
		}
		elsif ($name ne $item{$num}) {
			next unless length $name;
			my $src=$item{$num};
			
			if (! (-e $src || -l $src) ) {
				print STDERR "$0: $src does not exist\n";
				delete $item{$num};
				next;
			}

			# deal with swaps
			if (-e $name || -l $name) {
				my $tmp=$name."~";
				my $c=0;
				while (-e $tmp || -l $tmp) {
					$c++;
					$tmp=$name."~$c";
				}
				if (! rename($name, $tmp)) {
					print STDERR "$0: failed to rename $name to $tmp: $!\n";
					$error=1;
				}
				elsif ($verbose) {
					print "'$name' -> '$tmp'\n";
				}
				foreach my $item (keys %item) {
					if ($item{$item} eq $name) {
						$item{$item}=$tmp;
					}
				}
			}

			if (! rename($src, $name)) {
				print STDERR "$0: failed to rename $src to $name: $!\n";
				$error=1;
			}
			else {
				if (-d $name) {
					foreach (values %item) {
						s/^\Q$src\E/$name/;
					}
				}
				if ($verbose) {
					print "'$src' => '$name'\n";
				}
			}
		}
		delete $item{$num};
	}
	elsif (/^\s*$/) {
		# skip empty line
	}
	else {
		die "$0: unable to parse line \"$_\", aborting\n";
	}
}
close IN || die "$0: cannot read ".$tmp->filename.": $!\n";
unlink($tmp.'~') if -e $tmp.'~';

sub rm {
	my $file = shift;

	if (-d $file && ! -l $file) {
		return rmdir $file;
	}
	else {
		return unlink $file;
	}
}

foreach my $item (reverse sort values %item) {
	if (! rm($item)) {
		print STDERR "$0: failed to remove $item: $!\n";
		$error=1;
	}
	if ($verbose) {
		print "removed '$item'\n";
	}
}

exit $error;