package Test::Valgrind::FakeValgrind;

use strict;
use warnings;

use Config ();
use File::Spec;
use File::Temp;

sub _dummy_valgrind_code {
 my ($version, $body) = @_;

 my $perl = $^X;
 unless (-e $perl and -x $perl) {
  $perl = $Config::Config{perlpath};
  unless (-e $perl and -x $perl) {
   return undef;
  }
 }

 if (defined $body) {
  $body = "\n$body";
 } else {
  $body = '';
 }

 return <<" FAKE_VG";
#!$perl
if (\@ARGV == 1 && \$ARGV[0] eq '--version') {
 print "valgrind-$version\n";
 exit 0;
}$body
 FAKE_VG
}

sub new {
 my ($class, %args) = @_;

 my $exe_name = $args{exe_name};
 my $version  = $args{version} || '3.1.0';
 my $body     = $args{body};

 my $self = { };

 if (defined $exe_name) {
  $self->{tmp_dir_obj}  = File::Temp->newdir(CLEANUP => 1);
  $self->{tmp_dir}      = $self->{tmp_dir_obj}->dirname;
  $self->{tmp_file}     = File::Spec->catfile($self->{tmp_dir}, $exe_name);
 } else {
  $self->{tmp_file_obj} = File::Temp->new(UNLINK => 1);
  $self->{tmp_file}     = $self->{tmp_file_obj}->filename;
  my ($vol, $dir)       = File::Spec->splitpath($self->{tmp_file});
  $self->{tmp_dir}      = File::Spec->catpath($vol, $dir, '');
 }

 my $code = _dummy_valgrind_code($version, $body);
 return 'Could not generate the dummy valgrind executable' unless $code;

 return 'Temporary file already exists' if -s $self->{tmp_file};

 {
  open my $vg_fh, '>', $self->{tmp_file};
  print $vg_fh $code;
  close $vg_fh;
  chmod 0755, $self->{tmp_file};
 }

 bless $self, $class;
}

sub path { $_[0]->{tmp_file} }

sub dir  { $_[0]->{tmp_dir} }

1;
