#! @perl@ -w @perlFlags@

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

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

my $libexecDir = ($ENV{"NIX_LIBEXEC_DIR"} or "@libexecdir@");
my $storeDir = ($ENV{"NIX_STORE_DIR"} or "@storedir@");
my $stateDir = ($ENV{"NIX_STATE_DIR"} or "@localstatedir@/nix");
my $manifestDir = $Nix::Config::manifestDir;


# Prevent access problems in shared-stored installations.
umask 0022;


# Create the manifests directory if it doesn't exist.
if (! -e $manifestDir) {
    mkdir $manifestDir, 0755 or die "cannot create directory `$manifestDir'";
}


# Make sure that the manifests directory is scanned for GC roots.
my $gcRootsDir = "$stateDir/gcroots";
my $manifestDirLink = "$gcRootsDir/manifests";
if (! -l $manifestDirLink) {
    symlink($manifestDir, $manifestDirLink) or die "cannot create symlink `$manifestDirLink'";
}


# Process the URLs specified on the command line.
my %narFiles;
my %patches;

my $skipWrongStore = 0;

sub downloadFile {
    my $url = shift;
    $ENV{"PRINT_PATH"} = 1;
    $ENV{"QUIET"} = 1;
    my ($dummy, $path) = `$Nix::Config::binDir/nix-prefetch-url '$url'`;
    die "cannot fetch `$url'" if $? != 0;
    die "nix-prefetch-url did not return a path" unless defined $path;
    chomp $path;
    return $path;
}

sub processURL {
    my $url = shift;

    $url =~ s/\/$//;

    my $manifest;

    # First see if a bzipped manifest is available.
    if (system("$Nix::Config::curl --fail --silent --head '$url'.bz2 > /dev/null") == 0) {
        print "fetching list of Nix archives at `$url.bz2'...\n";
        my $bzipped = downloadFile "$url.bz2";

        $manifest = "$tmpDir/MANIFEST";

        system("$Nix::Config::bzip2 -d < $bzipped > $manifest") == 0
            or die "cannot decompress manifest";

        $manifest = (`$Nix::Config::binDir/nix-store --add $manifest`
                     or die "cannot copy $manifest to the store");
        chomp $manifest;
    }

    # Otherwise, just get the uncompressed manifest.
    else {
        print "obtaining list of Nix archives at `$url'...\n";
        $manifest = downloadFile $url;
    }

    my $version = readManifest($manifest, \%narFiles, \%patches);
    
    die "`$url' is not a manifest or it is too old (i.e., for Nix <= 0.7)\n" if $version < 3;
    die "manifest `$url' is too new\n" if $version >= 5;

    if ($skipWrongStore) {
        foreach my $path (keys %narFiles) {
            if (substr($path, 0, length($storeDir) + 1) ne "$storeDir/") {
                print STDERR "warning: manifest `$url' assumes a Nix store at a different location than $storeDir, skipping...\n";
                exit 0;
            }
        }
    }

    my $baseName = "unnamed";
    if ($url =~ /\/([^\/]+)\/[^\/]+$/) { # get the forelast component
        $baseName = $1;
    }

    my $hash = `$Nix::Config::binDir/nix-hash --flat '$manifest'`
        or die "cannot hash `$manifest'";
    chomp $hash;

    my $urlFile = "$manifestDir/$baseName-$hash.url";
    open URL, ">$urlFile" or die "cannot create `$urlFile'";
    print URL "$url";
    close URL;
    
    my $finalPath = "$manifestDir/$baseName-$hash.nixmanifest";

    unlink $finalPath if -e $finalPath;
        
    symlink("$manifest", "$finalPath")
        or die "cannot link `$finalPath to `$manifest'";

    # Delete all old manifests downloaded from this URL.
    for my $urlFile2 (glob "$manifestDir/*.url") {
        next if $urlFile eq $urlFile2;
        open URL, "<$urlFile2" or die;
        my $url2 = <URL>;
        chomp $url2;
        close URL;
        next unless $url eq $url2;
        my $base = $urlFile2; $base =~ s/.url$//;
        unlink "${base}.url";
        unlink "${base}.nixmanifest";
    }
}

while (@ARGV) {
    my $url = shift @ARGV;
    if ($url eq "--skip-wrong-store") {
        $skipWrongStore = 1;
    } else {
        processURL $url;
    }
}


my $size = scalar (keys %narFiles);
print "$size store paths in manifest\n";