#! /usr/bin/perl -w

use strict;
use POSIX qw(tmpnam);

my $pkgfile = $ARGV[0];
die unless defined $pkgfile;

my $tmpdir;
do { $tmpdir = tmpnam(); }
until mkdir $tmpdir, 0777;

# !!! remove tmpdir on exit

print "unpacking $pkgfile in $tmpdir...\n";
system "bunzip2 < $pkgfile | (cd $tmpdir && tar xf -)";
die if $?;

print "this package contains the following derivations:\n";
system "nix-env -qsf $tmpdir/default.nix";
die if $?;

print "do you wish to install them (y/n)? ";
my $reply = <STDIN>;
chomp $reply;
exit if (!($reply eq "y"));

print "pulling caches...\n";
system "nix-pull `cat $tmpdir/caches`";
die if $?;

print "installing package...\n";
system "nix-env -i $tmpdir/default.nix '*'";
die if $?;

print "installing succeeded! (enter to continue)\n";
<STDIN>;