#!/usr/bin/perl
use Test::Simple 'no_plan';
use File::Which;
# gnu xargs v 4.4 or more


ok( command_dependency( 'xargs', '4.2.27', 0 ), "have at least xargs 4.2.27");

ok( command_dependency( 'find', '4', 1 ), 'find 4');
ok( command_dependency( 'tar', '1.15' ), 'tar 1.15');


sub command_dependency {
   my ($name, $version, $debug)=@_;

   $^O=~/win/ and warn("Will not work on non posix systems.") and return;

   $debug or local $SIG{__WARN__} = sub { 1 };



   no warnings;
   require File::Which;
   my $which = File::Which::which($name) or return;
   
   warn("Got which $name: $which");



   if (defined $version){

      # version have..
      my $_version;

      # get version output
      if ( system("$which --version") == 0 ){ # some cli respond to -v instead of --version
         $_version = `$which --version`;
      }
      elsif ( system("$which -v") ==0 ){
         $_version = `$which -v`;
      }
      else { 
         warn("Command '$name' does not return version with -v or --version");
         return;
      }
      chomp $_version;
      warn("got '$_version'");

       

      # resolve to actual version string
      if( $_version=~/version\s+([\d\.]+)\b/ ){
         warn("match 1");
         $_version = $1;
      }
      elsif ( $_version=~/v\s*([\d\.]+)\b/ ){
         warn("match 2");
         $_version = $1;
      }
      elsif ( $_version=~/\b([\d\.]+)\b/ ){
         warn("match 3");
         $_version = $1;
      }
      else {
         warn("match missing, match into version output for '$name', didn't resolve to actual version string in '$_version'");
         return;
      }
      
      # test against version argument to sub

      my @version = split(/\./, $version);
      my @_version = split(/\./, $_version);

      # only test as far as argument provided go
      my $count= scalar @version; # i know, there are quicker ways to do this.. but..      
      # this is more clear for anybody viewing the code
      warn "count.. $count\n";
      my $index = 0;
      for ( 0 .. $count ){
         defined $version[$index] or next;
         if ( $version[$index] > $_version[$index] ){
         
            return 1; # obviously higher overall.
         }
         elsif ( $version[$index] < $_version[$index] ){
            return 0; # no high enough
         }
         $index++;
         # just high enough
         next;
      }
      # if we got here, have the version we want at least
      return 1;
   }

   # did not check version, but have command
   return 1;
}