#! @perl@ -w @perlFlags@

use strict;
use File::Temp qw(tempdir);
use Nix::Config;


sub usageError {
    print STDERR <<EOF;
Usage: nix-install-package (FILE | --url URL)

Install a Nix Package (.nixpkg) either directly from FILE or by
downloading it from URL.

Flags:
  --profile / -p LINK: install into the specified profile
  --non-interactive: don't run inside a new terminal
EOF
    ; # '
    exit 1;
}


# Parse the command line arguments.
my @args = @ARGV;
usageError if scalar @args == 0;

my $source;
my $fromURL = 0;
my @extraNixEnvArgs = ();
my $interactive = 1;

while (scalar @args) {
    my $arg = shift @args;
    if ($arg eq "--help") {
        usageError;
    }
    elsif ($arg eq "--url") {
        $fromURL = 1;
    }
    elsif ($arg eq "--profile" || $arg eq "-p") {
        my $profile = shift @args;
        usageError if !defined $profile;
        push @extraNixEnvArgs, "-p", $profile;
    }
    elsif ($arg eq "--non-interactive") {
        $interactive = 0;
    }
    else {
        $source = $arg;
    }
}

usageError unless defined $source;


# Re-execute in a terminal, if necessary, so that if we're executed
# from a web browser, the user gets to see us.
if ($interactive && !defined $ENV{"NIX_HAVE_TERMINAL"}) {
    $ENV{"NIX_HAVE_TERMINAL"} = "1";
    $ENV{"LD_LIBRARY_PATH"} = "";
    foreach my $term ("xterm", "konsole", "gnome-terminal", "xterm") {
        exec($term, "-e", "$Nix::Config::binDir/nix-install-package", @ARGV);
    }
    die "cannot execute `xterm'";
}


my $tmpDir = tempdir("nix-install-package.XXXXXX", CLEANUP => 1, TMPDIR => 1)
    or die "cannot create a temporary directory";


sub barf {
    my $msg = shift;
    print "$msg\n";
    <STDIN> if $interactive;
    exit 1;
}


# Download the package description, if necessary.
my $pkgFile = $source;
if ($fromURL) {
    $pkgFile = "$tmpDir/tmp.nixpkg";
    system("@curl@", "--silent", $source, "-o", $pkgFile) == 0
        or barf "curl failed: $?";
}


# Read and parse the package file.
open PKGFILE, "<$pkgFile" or barf "cannot open `$pkgFile': $!";
my $contents = <PKGFILE>;
close PKGFILE;

my $urlRE = "(?: [a-zA-Z][a-zA-Z0-9\+\-\.]*\:[a-zA-Z0-9\%\/\?\:\@\&\=\+\$\,\-\_\.\!\~\*\']+ )";
my $nameRE = "(?: [A-Za-z0-9\+\-\.\_\?\=]+ )"; # see checkStoreName()
my $systemRE = "(?: [A-Za-z0-9\+\-\_]+ )";
my $pathRE = "(?: \/ [\/A-Za-z0-9\+\-\.\_\?\=]* )";

# Note: $pathRE doesn't check that whether we're looking at a valid
# store path.  We'll let nix-env do that.

$contents =~
    / ^ \s* (\S+) \s+ ($urlRE) \s+ ($nameRE) \s+ ($systemRE) \s+ ($pathRE) \s+ ($pathRE) /x
    or barf "invalid package contents";
my $version = $1;
my $manifestURL = $2;
my $drvName = $3;
my $system = $4;
my $drvPath = $5;
my $outPath = $6;

barf "invalid package version `$version'" unless $version eq "NIXPKG1";


if ($interactive) {
    # Ask confirmation.
    print "Do you want to install `$drvName' (Y/N)? ";
    my $reply = <STDIN>;
    chomp $reply;
    exit if $reply ne "y" && $reply ne "Y";
}


# Store the manifest in the temporary directory so that we don't
# pollute /nix/var/nix/manifests.  This also requires that we don't
# use the Nix daemon (because otherwise download-using-manifests won't
# see our NIX_MANIFESTS_DIRS environment variable).
$ENV{NIX_MANIFESTS_DIR} = $tmpDir;
$ENV{NIX_REMOTE} = "";


print "\nPulling manifests...\n";
system("$Nix::Config::binDir/nix-pull", $manifestURL) == 0
    or barf "nix-pull failed: $?";


print "\nInstalling package...\n";
system("$Nix::Config::binDir/nix-env", "--install", $outPath, "--force-name", $drvName, @extraNixEnvArgs) == 0
    or barf "nix-env failed: $?";


if ($interactive) {
    print "\nInstallation succeeded! Press Enter to continue.\n";
    <STDIN>;
}