#!/usr/bin/perl
use strict;
use warnings;

use lib $ENV{GL_LIBDIR};
use Gitolite::Rc;
use Gitolite::Common;

=for usage
Usage for this command is not that simple.  Please read the full documentation
in doc/sskm.mkd or online at http://gitolite.com/gitolite/sskm.html.
=cut

usage() if @ARGV and $ARGV[0] eq '-h';

my $rb = $rc{GL_REPO_BASE};
my $ab = $rc{GL_ADMIN_BASE};
# get to the keydir
_chdir("$ab/keydir");

# save arguments for later
my $operation = shift || 'list';
my $keyid     = shift || '';
# keyid must fit a very specific pattern
$keyid and $keyid !~ /^@[-0-9a-z_]+$/i and die "invalid keyid $keyid\n";

# get the actual userid and keytype
my $gl_user = $ENV{GL_USER};
my $keytype = '';
$keytype = $1 if $gl_user =~ s/^zzz-marked-for-(...)-//;
print STDERR "hello $gl_user, you are currently using "
  . (
    $keytype
    ? "a key in the 'marked for $keytype' state\n"
    : "a normal (\"active\") key\n"
  );

# ----
# first collect the keys

my ( @pubkeys, @marked_for_add, @marked_for_del );
# get the list of pubkey files for this user, including pubkeys marked for
# add/delete

for my $pubkey (`find . -type f -name "*.pub" | sort`) {
    chomp($pubkey);
    $pubkey =~ s(^./)();    # artifact of the find command

    my $user = $pubkey;
    $user =~ s(.*/)();                # foo/bar/baz.pub -> baz.pub
    $user =~ s/(\@[^.]+)?\.pub$//;    # baz.pub, baz@home.pub -> baz

    next unless $user eq $gl_user or $user =~ /^zzz-marked-for-...-$gl_user/;

    if ( $user =~ m(^zzz-marked-for-add-) ) {
        push @marked_for_add, $pubkey;
    } elsif ( $user =~ m(^zzz-marked-for-del-) ) {
        push @marked_for_del, $pubkey;
    } else {
        push @pubkeys, $pubkey;
    }
}

# ----
# list mode; just do it and exit
sub print_keylist {
    my ( $message, @list ) = @_;
    return unless @list;
    print "== $message ==\n";
    my $count = 1;
    for (@list) {
        my $fp = fingerprint($_);
        s/zzz-marked(\/|-for-...-)//g;
        print $count++ . ": $fp : $_\n";
    }
}
if ( $operation eq 'list' ) {
    print "you have the following keys:\n";
    print_keylist( "active keys",                          @pubkeys );
    print_keylist( "keys marked for addition/replacement", @marked_for_add );
    print_keylist( "keys marked for deletion",             @marked_for_del );
    print "\n\n";
    exit;
}

# ----
# please see docs for details on how a user interacts with this

if ( $keytype eq '' ) {
    # user logging in with a normal key
    die "valid operations: add, del, undo-add, confirm-del\n" unless $operation =~ /^(add|del|confirm-del|undo-add)$/;
    if ( $operation eq 'add' ) {
        print STDERR "please supply the new key on STDIN.  (I recommend you
        don't try to do this interactively, but use a pipe)\n";
        kf_add( $gl_user, $keyid, safe_stdin() );
    } elsif ( $operation eq 'del' ) {
        kf_del( $gl_user, $keyid );
    } elsif ( $operation eq 'confirm-del' ) {
        die "you dont have any keys marked for deletion\n" unless @marked_for_del;
        kf_confirm_del( $gl_user, $keyid );
    } elsif ( $operation eq 'undo-add' ) {
        die "you dont have any keys marked for addition\n" unless @marked_for_add;
        kf_undo_add( $gl_user, $keyid );
    }
} elsif ( $keytype eq 'del' ) {
    # user is using a key that was marked for deletion.  The only possible use
    # for this is that she changed her mind for some reason (maybe she marked
    # the wrong key for deletion) or is not able to get her client-side sshd
    # to stop using this key
    die "valid operations: undo-del\n" unless $operation eq 'undo-del';

    # reinstate the key
    kf_undo_del( $gl_user, $keyid );
} elsif ( $keytype eq 'add' ) {
    die "valid operations: confirm-add\n" unless $operation eq 'confirm-add';
    # user is trying to validate a key that has been previously marked for
    # addition.  This isn't interactive, but it *could* be... if someone asked
    kf_confirm_add( $gl_user, $keyid );
}

exit;

# ----

# make a temp clone and switch to it
our $TEMPDIR;
BEGIN { $TEMPDIR = `mktemp -d -t tmp.XXXXXXXXXX`; }
END { `/bin/rm -rf $TEMPDIR`; }

sub cd_temp_clone {
    chomp($TEMPDIR);
    hushed_git( "clone", "$rb/gitolite-admin.git", "$TEMPDIR" );
    chdir($TEMPDIR);
    my $hostname = `hostname`; chomp($hostname);
    hushed_git( "config", "--get", "user.email" ) and hushed_git( "config", "user.email", $ENV{USER} . "@" . $hostname );
    hushed_git( "config", "--get", "user.name" )  and hushed_git( "config", "user.name",  "$ENV{USER} on $hostname" );
}

sub fingerprint {
    my ($fp, $output) = ssh_fingerprint_file(shift);
    # Do not print the output of $output to an untrusted destination.
    die "does not seem to be a valid pubkey\n" unless $fp;
    return $fp;
}

sub safe_stdin {
    # read one line from STDIN
    my $data;
    my $ret = read STDIN, $data, 4096;
    # current pubkeys are approx 400 bytes so we go a little overboard
    die "could not read pubkey data" . ( defined($ret) ? "" : ": $!" ) . "\n" unless $ret;
    die "pubkey data seems to have more than one line\n" if $data =~ /\n./;
    return $data;
}

sub hushed_git {
    local (*STDOUT) = \*STDOUT;
    local (*STDERR) = \*STDERR;
    open( STDOUT, ">", "/dev/null" );
    open( STDERR, ">", "/dev/null" );
    system( "git", @_ );
}

sub highlander {
    # there can be only one
    my ( $keyid, $die_if_empty, @a ) = @_;
    # too many?
    if ( @a > 1 ) {
        print STDERR "
more than one key satisfies this condition, and I can't deal with that!
The keys are:

";
        print STDERR "\t" . join( "\n\t", @a ), "\n\n";
        exit 1;
    }
    # too few?
    die "no keys with " . ( $keyid || "empty" ) . " keyid found\n" if $die_if_empty and not @a;

    return @a;
}

sub kf_add {
    my ( $gl_user, $keyid, $keymaterial ) = @_;

    # add a new "marked for addition" key for $gl_user.
    cd_temp_clone();
    chdir("keydir");

    mkdir("zzz-marked");
    _print( "zzz-marked/zzz-marked-for-add-$gl_user$keyid.pub", $keymaterial );
    hushed_git( "add", "." ) and die "git add failed\n";
    my $fp = fingerprint("zzz-marked/zzz-marked-for-add-$gl_user$keyid.pub");
    hushed_git( "commit", "-m", "sskm: add $gl_user$keyid ($fp)" ) and die "git commit failed\n";
    system("gitolite push >/dev/null 2>/dev/null") and die "git push failed\n";
}

sub kf_confirm_add {
    my ( $gl_user, $keyid ) = @_;
    # find entries in both @pubkeys and @marked_for_add whose basename matches $gl_user$keyid
    my @pk  = highlander( $keyid, 0, grep { m(^(.*/)?$gl_user$keyid.pub$) } @pubkeys );
    my @mfa = highlander( $keyid, 1, grep { m(^zzz-marked/zzz-marked-for-add-$gl_user$keyid.pub$) } @marked_for_add );

    cd_temp_clone();
    chdir("keydir");

    my $fp = fingerprint( $mfa[0] );
    if ( $pk[0] ) {
        hushed_git( "mv", "-f", $mfa[0], $pk[0] );
        hushed_git( "commit", "-m", "sskm: confirm-add (replace) $pk[0] ($fp)" ) and die "git commit failed\n";
    } else {
        hushed_git( "mv", "-f", $mfa[0], "$gl_user$keyid.pub" );
        hushed_git( "commit", "-m", "sskm: confirm-add $gl_user$keyid ($fp)" ) and die "git commit failed\n";
    }
    system("gitolite push >/dev/null 2>/dev/null") and die "git push failed\n";
}

sub kf_undo_add {
    # XXX some code at start is shared with kf_confirm_add
    my ( $gl_user, $keyid ) = @_;
    my @mfa = highlander( $keyid, 1, grep { m(^zzz-marked/zzz-marked-for-add-$gl_user$keyid.pub$) } @marked_for_add );

    cd_temp_clone();
    chdir("keydir");

    my $fp = fingerprint( $mfa[0] );
    hushed_git( "rm", $mfa[0] );
    hushed_git( "commit", "-m", "sskm: undo-add $gl_user$keyid ($fp)" ) and die "git commit failed\n";
    system("gitolite push >/dev/null 2>/dev/null") and die "git push failed\n";
}

sub kf_del {
    my ( $gl_user, $keyid ) = @_;

    cd_temp_clone();
    chdir("keydir");

    mkdir("zzz-marked");
    my @pk = highlander( $keyid, 1, grep { m(^(.*/)?$gl_user$keyid.pub$) } @pubkeys );

    my $fp = fingerprint( $pk[0] );
    hushed_git( "mv", $pk[0], "zzz-marked/zzz-marked-for-del-$gl_user$keyid.pub" ) and die "git mv failed\n";
    hushed_git( "commit", "-m", "sskm: del $pk[0] ($fp)" ) and die "git commit failed\n";
    system("gitolite push >/dev/null 2>/dev/null") and die "git push failed\n";
}

sub kf_confirm_del {
    my ( $gl_user, $keyid ) = @_;
    my @mfd = highlander( $keyid, 1, grep { m(^zzz-marked/zzz-marked-for-del-$gl_user$keyid.pub$) } @marked_for_del );

    cd_temp_clone();
    chdir("keydir");

    my $fp = fingerprint( $mfd[0] );
    hushed_git( "rm", $mfd[0] );
    hushed_git( "commit", "-m", "sskm: confirm-del $gl_user$keyid ($fp)" ) and die "git commit failed\n";
    system("gitolite push >/dev/null 2>/dev/null") and die "git push failed\n";
}

sub kf_undo_del {
    my ( $gl_user, $keyid ) = @_;

    my @mfd = highlander( $keyid, 1, grep { m(^zzz-marked/zzz-marked-for-del-$gl_user$keyid.pub$) } @marked_for_del );

    print STDERR "
You're undeleting a key that is currently marked for deletion.
    Hit ENTER to undelete this key
    Hit Ctrl-C to cancel the undelete
Please see documentation for caveats on the undelete process as well as how to
actually delete it.
";
    <>;    # yeay... always wanted to do that -- throw away user input!

    cd_temp_clone();
    chdir("keydir");

    my $fp = fingerprint( $mfd[0] );
    hushed_git( "mv", "-f", $mfd[0], "$gl_user$keyid.pub" );
    hushed_git( "commit", "-m", "sskm: undo-del $gl_user$keyid ($fp)" ) and die "git commit failed\n";
    system("gitolite push >/dev/null 2>/dev/null") and die "git push failed\n";
}