#!/usr/bin/env perl
use strict;
use warnings;
use Carp;
use Pod::Usage qw( pod2usage );
use Getopt::Long qw( :config gnu_getopt );
my $VERSION = '1.0';
use English qw( -no_match_vars );
use Fatal qw( open );
use Storable qw( thaw fd_retrieve );
use File::Spec::Functions qw( catdir catfile splitpath );
use File::Path qw( mkpath );
use Template::Perlish;

my %config = (source => '', dest => '', process => '.');
GetOptions(
   \%config,                    'usage',
   'help',                      'man',
   'version',                   'source|src|s=s',
   'dest|dst|d=s',              'define|D=s@',
   'hdefine|hex-define|H|X=s@', 'sdefine|storable-define|S=s@',
   'edefine|eval-define|E=s@',  'sstdin|storable-stdin|i!',
   'process|p=s',               'verbose|v!',
   'variables|V!',
);

pod2usage(message => "$0 $VERSION", -verbose => 99, -sections => '')
  if $config{version};
pod2usage(-verbose => 99, -sections => 'USAGE') if $config{usage};
pod2usage(-verbose => 99, -sections => 'USAGE|EXAMPLES|OPTIONS')
  if $config{help};
pod2usage(-verbose => 2) if $config{man};

# Script implementation here
die 'no source directory, bailing out' unless -d $config{source};
die 'no destination directory, bailing out' unless defined $config{dest};
if (!-d $config{dest}) {
   mkpath([$config{dest}])
     or die "could not create destination directory '$config{dest}'";
}

my $variables = get_variables();
if ($config{variables}) {
   require Data::Dumper;
   print {*STDERR} "Configuration: ", Data::Dumper::Dumper($variables);
}
my $tp            = Template::Perlish->new(variables => $variables);
my $it            = input_file_iterator();
my $process_regex = qr/$config{process}/;
while (defined(my $file = $it->())) {
   my $source = catfile($config{source}, $file);
   my $dest   = catfile($config{dest},   $file);
   my ($vol, $dir,) = splitpath($dest);
   if (!-d (my $destdir = $vol . $dir)) {
      mkpath([$destdir]);
   }

   print {*STDERR} $file, "\n" if $config{verbose};
   my $template = read_file($source);
   my $output =
     $file =~ m{$process_regex} ? $tp->process($template) : $template;
   write_file($dest, $output);
} ## end while (defined(my $file =...
exit 0;

sub input_file_iterator {
   my @dirstack = '.';
   my @files;
   return sub {
      while (!@files) {
         return unless @dirstack;
         my $dir = shift @dirstack;
         my $fulldir = catdir($config{source}, $dir);
         opendir my $d, $fulldir or die "opendir(): $OS_ERROR";
         while (defined(my $item = readdir $d)) {
            next if $item eq '.' || $item eq '..';
            my $relpath = catfile($dir, $item);
            if (-d catfile($config{source}, $relpath)) {
               push @dirstack, $relpath;
            }
            else {
               push @files, $relpath;
            }
         } ## end while (defined(my $item =...
         closedir $d;
      } ## end while (!@files)

      return shift @files;
   };
} ## end sub input_file_iterator

sub get_variables {
   my %variables;
   for my $dtype (qw( define edefine hdefine sdefine )) {
      my $definitions = $config{$dtype};
      my $filter      = {
         define  => sub { shift },
         edefine => sub { eval shift },
         hdefine => sub { pack 'H*', shift },
         sdefine => sub { thaw pack 'H*', shift },
      }->{$dtype};
      for my $definition (@$definitions) {
         my ($name, $value) = split /=/, $definition, 2;
         $variables{$name} = defined $value ? $filter->($value) : 1;
      }
   } ## end for my $dtype (qw( define edefine hdefine sdefine ))

   if (exists $config{sstdin}) {
      my $href = fd_retrieve(\*STDIN);
      while (my ($k, $v) = each %$href) {
         $variables{$k} = $v;
      }
   } ## end if (exists $config{sstdin...

   return %variables if wantarray;
   return \%variables;
} ## end sub get_variables

sub read_file {
   my ($input) = @_;
   my $fh =
     ref($input)
     ? $input
     : do { open my $fh, '<', $input; $fh };
   local $INPUT_RECORD_SEPARATOR;    # to slurp whole file
   binmode $fh;
   my $retval = <$fh>;
   close $fh unless ref $input;
   return $retval;
} ## end sub read_file

sub write_file {
   my $output = shift;
   my $fh =
     ref($output)
     ? $output
     : do { open my $fh, '>', $output; $fh };
   binmode $fh;
   print {$fh} @_;
   close $fh unless ref $output;
   return;
} ## end sub write_file

__END__

=head1 NAME

tptree - a very humble imitation of ttree from TT2

=head1 VERSION

Ask the version number to the script itself, calling:

   shell$ tptree --version


=head1 USAGE

   tptree [--usage] [--help] [--man] [--version]

   tptree [--source|--src|-s directory] [--dest|--dst|-d directory]
      [--process|-p regex] [--verbose|-v] [--variables|-V]
      [--define|-D item] [--edefine|--eval-define|-E item]
      [--hdefine|--hex-define|-H|-X item] 
      [--sdefine|--storable-define|-S item]
      [--sstdin|--storable-stdin|-i]

=head1 EXAMPLES

   shell$ tptree

   shell$ tptree --src source --dst /path/to/dst --define ciao='a tutti'

=head1 DESCRIPTION

This simple script tries to capture what I've personally found to be 90%
of the useful functionality in TT2: recursing into a given file tree, 
apply the transformations with the templating system, and put the result
into a directory tree analogous to the starting one, but where I desire.

As a minimum, you have to provide a source directory and a destination.
Every output directory that's not already there will be created, so
the destination directory needs not to be previously created.

During processing, you can decide which files should be included by
providing a selection regular expression through C<--process|-p>.

One aspect where tptree goes quite on its own way is variable passing.
While TT2's ttree is bound to simple C<variable=value> paradigm, tptree
offers a wide variety for both escaping/encoding the variables, or
get them via standard input (<--sstdin|--storable-stdin|-i>).

=head1 OPTIONS

Parameter passing options are discussed in a section by themselves, to
be found later in this document.

=over

=item --dest | --dst | -d directory

set the destination directory root.

=item --help

print a somewhat more verbose help, showing usage, this description of
the options and some examples from the synopsis.

=item --man

print out the full documentation for the script.

=item --process | -p regex

set the given regex as a regular expression to be matched on each
filename found in the hierarchy. If matches, the file is "executed",
otherwise.

=item --source | --src | -s directory

set the source directory for directory root.

=item --usage

print a concise usage line and exit.

=item --variables | -V

print a dump of the configured variables.

=item --verbose | -v

output some debug messages during execution.

=item --version

print the version of the script.

=back

=head2 Variable Passing

There are three variables-setting facilities that can be used on the
command line:

=over

=item --define | -D name=value

set name as value

=item --edefine | --eval-define | -E name=expression

evaluate expression and set name to the result. So, for example you can
say:

   name='[qw(ciao a tutti)]'

and get name set to an anonymous array containing three elements
(guess which?)

=item --hdefine | --hex-define | -H | -X name=hexvalue

convert hexvalue back to unencoded form, using C<pack>'s template
'H*', then set as the value of variable C<name>.

=item --sdefine | --storable-define | -S name=storable-hex

convert storable-hex back into binary data (using 'H*'), then retrieve
a value using Storable.

=back

Last, but not least, a set of variables embedded into a hash ref
encoded with Storable can be read from the standard input:

=over

=item --sstdin | --storable-stdin | -i!

get configuration from standard input, decoding it using Storable.

=back

=head1 CONFIGURATION AND ENVIRONMENT

tptree requires no configuration files or environment variables.


=head1 DEPENDENCIES

None, apart Template::Perlish. Unless it has been embedded in this very
file.


=head1 BUGS AND LIMITATIONS

No bugs have been reported.

Please report any bugs or feature requests through http://rt.cpan.org/


=head1 AUTHOR

Flavio Poletti C<flavio@polettix.it>


=head1 LICENCE AND COPYRIGHT

Copyright (c) 2008, Flavio Poletti C<flavio@polettix.it>. All rights reserved.

This script is free software; you can redistribute it and/or
modify it under the same terms as Perl itself. See L<perlartistic>
and L<perlgpl>.

Questo script è software libero: potete ridistribuirlo e/o
modificarlo negli stessi termini di Perl stesso. Vedete anche
L<perlartistic> e L<perlgpl>.


=head1 DISCLAIMER OF WARRANTY

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE
LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL,
OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

=head1 NEGAZIONE DELLA GARANZIA

Poiché questo software viene dato con una licenza gratuita, non
c'è alcuna garanzia associata ad esso, ai fini e per quanto permesso
dalle leggi applicabili. A meno di quanto possa essere specificato
altrove, il proprietario e detentore del copyright fornisce questo
software "così com'è" senza garanzia di alcun tipo, sia essa espressa
o implicita, includendo fra l'altro (senza però limitarsi a questo)
eventuali garanzie implicite di commerciabilità e adeguatezza per
uno scopo particolare. L'intero rischio riguardo alla qualità ed
alle prestazioni di questo software rimane a voi. Se il software
dovesse dimostrarsi difettoso, vi assumete tutte le responsabilità
ed i costi per tutti i necessari servizi, riparazioni o correzioni.

In nessun caso, a meno che ciò non sia richiesto dalle leggi vigenti
o sia regolato da un accordo scritto, alcuno dei detentori del diritto
di copyright, o qualunque altra parte che possa modificare, o redistribuire
questo software così come consentito dalla licenza di cui sopra, potrà
essere considerato responsabile nei vostri confronti per danni, ivi
inclusi danni generali, speciali, incidentali o conseguenziali, derivanti
dall'utilizzo o dall'incapacità di utilizzo di questo software. Ciò
include, a puro titolo di esempio e senza limitarsi ad essi, la perdita
di dati, l'alterazione involontaria o indesiderata di dati, le perdite
sostenute da voi o da terze parti o un fallimento del software ad
operare con un qualsivoglia altro software. Tale negazione di garanzia
rimane in essere anche se i dententori del copyright, o qualsiasi altra
parte, è stata avvisata della possibilità di tali danneggiamenti.

Se decidete di utilizzare questo software, lo fate a vostro rischio
e pericolo. Se pensate che i termini di questa negazione di garanzia
non si confacciano alle vostre esigenze, o al vostro modo di
considerare un software, o ancora al modo in cui avete sempre trattato
software di terze parti, non usatelo. Se lo usate, accettate espressamente
questa negazione di garanzia e la piena responsabilità per qualsiasi
tipo di danno, di qualsiasi natura, possa derivarne.

=cut