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

use ssh;

my $binDir = $ENV{"NIX_BIN_DIR"} || "@bindir@";


if (scalar @ARGV < 1) {
    print STDERR <<EOF
Usage: nix-copy-closure [--from | --to] HOSTNAME [--sign] [--gzip] PATHS...
EOF
    ;
    exit 1;
}


# Get the target host.
my $sshHost;

my $sign = 0;

my $compressor = "";
my $decompressor = "";

my $toMode = 1;


# !!! Copied from nix-pack-closure, should put this in a module.
my @storePaths = ();

while (@ARGV) {
    my $arg = shift @ARGV;
    
    if ($arg eq "--sign") {
        $sign = 1;
    }
    elsif ($arg eq "--gzip") {
        $compressor = "| gzip";
        $decompressor = "gunzip |";
    }
    elsif ($arg eq "--from") {
        $toMode = 0;
    }
    elsif ($arg eq "--to") {
        $toMode = 1;
    }
    elsif (!defined $sshHost) {
        $sshHost = $arg;
    }
    else {
        push @storePaths, $arg;
    }
}


openSSHConnection $sshHost or die "$0: unable to start SSH\n";


if ($toMode) { # Copy TO the remote machine.

    my @allStorePaths;

    # Get the closure of this path.
    my $pid = open(READ, "$binDir/nix-store --query --requisites @storePaths|") or die;
    
    while (<READ>) {
        chomp;
        die "bad: $_" unless /^\//;
        push @allStorePaths, $_;
    }

    close READ or die "nix-store failed: $?";


    # Ask the remote host which paths are invalid.
    open(READ, "ssh $sshHost @sshOpts nix-store --check-validity --print-invalid @allStorePaths|");
    my @missing = ();
    while (<READ>) {
        chomp;
        push @missing, $_;
    }
    close READ or die;


    # Export the store paths and import them on the remote machine.
    if (scalar @missing > 0) {
        print STDERR "copying these missing paths:\n";
        print STDERR "  $_\n" foreach @missing;
        my $extraOpts = "";
        $extraOpts .= "--sign" if $sign == 1;
        system("nix-store --export $extraOpts @missing $compressor | ssh $sshHost @sshOpts '$decompressor nix-store --import'") == 0
            or die "copying store paths to remote machine `$sshHost' failed: $?";
    }

}


else { # Copy FROM the remote machine.

    # Query the closure of the given store paths on the remote
    # machine.  Paths are assumed to be store paths; there is no
    # resolution (following of symlinks).
    my $pid = open(READ,
        "ssh @sshOpts $sshHost nix-store --query --requisites @storePaths|") or die;
    
    my @allStorePaths;

    while (<READ>) {
        chomp;
        die "bad: $_" unless /^\//;
        push @allStorePaths, $_;
    }

    close READ or die "nix-store on remote machine `$sshHost' failed: $?";


    # What paths are already valid locally?
    open(READ, "@bindir@/nix-store --check-validity --print-invalid @allStorePaths|");
    my @missing = ();
    while (<READ>) {
        chomp;
        push @missing, $_;
    }
    close READ or die;
    

    # Export the store paths on the remote machine and import them on locally.
    if (scalar @missing > 0) {
        print STDERR "copying these missing paths:\n";
        print STDERR "  $_\n" foreach @missing;
        my $extraOpts = "";
        $extraOpts .= "--sign" if $sign == 1;
        system("ssh $sshHost @sshOpts 'nix-store --export $extraOpts @missing $compressor' | $decompressor @bindir@/nix-store --import") == 0
            or die "copying store paths from remote machine `$sshHost' failed: $?";
    }

}