#!/usr/bin/perl -w

use strict;

print "template v1.1 - General purpose templating system\n".
        "  (c) 2003 - JaWi, janwillem.janssen\@lxtreme.nl\n\n";

my %config = configure( "/home/jawi/.templaterc" );
$config{ filename } = question( "Please give template (output) filename" );
( $config{ base_filename } ) = ( $config{ filename } =~ m/^([^.]+)/ );

my %templates = get_templates( $config{ templates } );
my $template_no = ask_for_template( %templates );
my @template = make_template( $templates{ $template_no }, %config );

my $output_file = $config{ filename };
if ( ! -e $output_file || question( "Overwrite? [y/n]" ) =~ /y(es)?/i )
{     
  open OUTPUT, ">$output_file" or die "Can't write to $output_file...\n";
  print OUTPUT foreach ( @template );
  close OUTPUT;
}

### END ###

sub make_template
{
  my ( $file, %config ) = @_;
  my @template;

  open TPL, "<$file" or die "Can't open template file!\n";
  @template = <TPL>;
  close TPL;

  s/%(\w+)%/$config{lc $1}?$config{lc $1}:question(lc $1)/eig
        foreach ( @template );

  @template;
} # make_template

sub ask_for_template
{
  my ( %templates ) = @_;
  my @indexes = sort keys %templates;
  my $idx = 0;
  printf "  [% 2d] %s\n", ++$idx, $indexes[ $idx - 1 ] foreach ( @indexes );
  $idx = 0;
  while ( $idx < 1 || $idx > scalar @indexes )
  {
    $idx = question( "Template number" );
  }
  $indexes[ $idx - 1 ];
} # ask_for_template

sub get_templates
{
  my ( $template_dir ) = @_;
  my %template;
  while ( <$template_dir/*.tpl> )
  {
    /^$template_dir\/([\w_.-]+)\.tpl$/ and $template{ $1 } = $_ if ( -e && -R );
  }

  %template;
} # get_templates

sub configure
{
  my ( $config_file ) = @_;
  my %config =
        ( name => "Your full name", 
          nick => "Your nick name", 
          company => "Your company",
          email => "Your email address",
          templates => "Path to templates" );

  if ( ! -e $config_file )
  {
    print "First time configuration:\n\n";
    $config{ $_ } = question( $config{ $_ } ) foreach ( keys %config );

    open CONFIG, ">$config_file" or die "Can't write to $config_file...\n";
    print CONFIG "# template configuration file\n";
    print CONFIG "  $_ = $config{$_}\n" foreach ( keys %config );
    close CONFIG;

    print "\n";
  }
  elsif ( -R $config_file )
  {
    open CONFIG, "<$config_file" or die "Can't read from $config_file...\n";
    while ( <CONFIG> )
    {
      next if /^#/ or /^\s*$/;
      my ( $key, $value ) = ( /\s*(\w+)\s*=\s*([^\n#]+)?/ );
      $config{ $key } = $value if defined $config{ $key };
    }
    close CONFIG;
  }  
  else
  {
    die "Can't read from $config_file...\n";
  }

  %config;
} # configure

sub question
{
  printf( "%20s: ", $_[0] );
  my $retval = <>; chomp $retval;
  $retval;
} # question
=pod

=head1 Name

template

=head1 Description

Simple templating system for source files.
This program allows you to generate various files based on simple
templates.  For example, you could generate a basic Perl skeleton
with your name, email and other information automatically filled in.

=head2 Predefined variables

There are currently several predefined variables defined for
template. Variable names exist only of printable characters (that is
a-z, 0-9, '.' and '_') and are wrapped with a leading and trailing
percentage sign (%).

=head3 %name%, %nick%, %company%, %email%

These variables are set upon the first time you run template. It will
expand to your name, nickname, company and email-address.

=head3 %filename%

This variable will expand to the full filename of the output file,
that is, with extension.
=head3 %base_filename%

This variable will be replaced with the base name of the output
filename (e.g.  without extension(s)). This could be useful, for
example, when you want to generate Java or C++ class files.

=head2 Adding variables

You can add your own variables by simply inserting them into your
templates.  Remember to embed them inside two percentage signs! If
the program comes across a variable it doesn't know, it will prompt
you for a value before continuing.

=head1 Templates

In principal every file can act as template file. The only
restriction is that the extension ends in C<.tpl>. An example for a
template providing a basic Perl snippet skeleton would look like
this:

#!/usr/bin/perl -w

use strict;

### END ###

Z<>=pod

Z<>=head1 Name

%base_filename%

Z<>=head1 Description

...

Z<>=head1 Updates

...

Z<>=head1 Author

%nick%,
CZ<><%email%>

Z<>=cut

=head1 Todos

Suggestion of template file based on the extension of the output
file.  Add some verbose input checking.

=head1 Updates

2003-01-08  21:15
   Fixed a minor bug regarding multiple variables on a single line.

=head1 Author

JaWi,
C<janwillem.janssen@lxtreme.nl>

=cut