#! @perl@ -w -I@libexecdir@/nix

use strict;
use IPC::Open2;
use POSIX qw(tmpnam);
use readmanifest;

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

my $manifest = "$tmpdir/manifest";

#END { unlink $manifest; rmdir $tmpdir; }


# Obtain URLs either from the command line or from a configuration file.
my %narFiles;
my %patches;
my %successors;

sub processURL {
    my $url = shift;

    $url =~ s/\/$//;
    print "obtaining list of Nix archives at $url...\n";

    system("@curl@ --fail --silent --show-error --location --max-redirs 20 " .
           "'$url' > '$manifest'") == 0
           or die "curl failed: $?";
    
    readManifest $manifest, \%narFiles, \%patches, \%successors;
}

while (@ARGV) {
    my $url = shift @ARGV;
    processURL $url;
}


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


# Instantiate a store expression that builds the substitute program
# (the program that fetches URLs and unpacks them into the store).
my $nixExpr =
    "(import @datadir@/nix/corepkgs/nix-pull) " .
    "{system = \"@system@\";}";

print STDERR "building downloader...\n";
my $substProgram = `echo '$nixExpr' | @bindir@/nix-store -qnf \$(@bindir@/nix-instantiate -)`
    or die "cannot instantiate Nix expression";
chomp $substProgram;


# Register all substitutes.
print STDERR "registering substitutes...\n";

my $pid = open2(\*READ, \*WRITE, "@bindir@/nix-store --substitute")
    or die "cannot run nix-store";

close READ;

foreach my $storePath (keys %narFiles) {
    my $narFileList = $narFiles{$storePath};
    foreach my $narFile (@{$narFileList}) {
        print WRITE "$storePath\n";
        print WRITE "$substProgram/fetch\n";
        print WRITE "2\n";
        print WRITE "$narFile->{url}\n";
        print WRITE "$narFile->{hash}\n";
    }
}

close WRITE;

waitpid $pid, 0;
$? == 0 or die "nix-store failed";


# Register all successors.
print STDERR "registering successors...\n";
my @sucs = %successors;
while (scalar @sucs > 0) {
    my $n = scalar @sucs;
    if ($n > 256) { $n = 256 };
    my @sucs2 = @sucs[0..$n - 1];
    @sucs = @sucs[$n..scalar @sucs - 1];
    system "@bindir@/nix-store --successor @sucs2";
    if ($?) { die "`nix-store --successor' failed"; }
}