# /MLOCK <channel> <mode>
#
# Locks the channel mode to <mode>, if someone else tries to change the mode
# Irssi will automatically change it back. +k and +l are a bit special since
# they require the parameter. If you omit the parameter, like setting the
# mode to "+ntlk", Irssi will allow all +k and +l (or -lk) mode changes.
# You can remove the lock with /MODE #channel -

use Irssi;
use Irssi::Irc;
use strict;
use vars qw($VERSION %IRSSI);

$VERSION = "1.00";
%IRSSI = (
    authors     => 'Timo Sirainen',
    name        => 'mlock',
    description => 'Channel mode locking',
    license     => 'Public Domain',
    changed    => 'Sun Mar 10 23:18 EET 2002'
);

my %keep_channels;

sub cmd_mlock {
    my ($data, $server) = @_;
    my ($channel, $mode) = split(/ /, $data, 2);

    if ($mode eq "-") {
        # remove checking
        delete $keep_channels{$channel};
    } else {
        $keep_channels{$channel} = $mode;
        mlock_check_mode($server, $channel);
    }
}

sub mlock_check_mode {
        my ($server, $channame) = @_;

    my $channel = $server->channel_find($channame);
    return if (!$channel || !$channel->{chanop});

        my $keep_mode = $keep_channels{$channame};
    return if (!$keep_mode);

    # old channel mode
    my ($oldmode, $oldkey, $oldlimit);
    $oldmode = $channel->{mode};
        $oldmode =~ s/^([^ ]*).*/\1/;
    $oldkey = $channel->{key};
    $oldlimit = $channel->{limit};

    # get the new channel key/limit
    my (@newmodes, $newkey, $limit);
    @newmodes = split(/ /, $keep_mode); $keep_mode = $newmodes[0];
    if ($keep_mode =~ /k/) {
        if ($keep_mode =~ /k.*l/) {
                        $newkey = $newmodes[1];
                        $limit = $newmodes[2];
        } elsif ($keep_mode =~ /l.*k/) {
            $limit = $newmodes[1];
                        $newkey = $newmodes[2];
        } else {
                        $newkey = $newmodes[1];
        }
    } elsif ($keep_mode =~ /l/) {
        $limit = $newmodes[1];
    }

    # check the differences
    my %allmodes;
    $keep_mode =~ s/^\+//;
    for (my $n = 0; $n < length($keep_mode); $n++) {
        my $modechar = substr($keep_mode, $n, 1);
        $allmodes{$modechar} = '+';
    }

    for (my $n = 0; $n < length($oldmode); $n++) {
        my $modechar = substr($oldmode, $n, 1);

        if ($allmodes{$modechar} eq '+') {
            next if (($modechar eq "k" && $newkey ne $oldkey) ||
                 ($modechar eq "l" && $limit != $oldlimit));
            delete $allmodes{$modechar};
        } else {
            $allmodes{$modechar} = '-';
        }
    }

    # create the mode change string
    my ($modecmd, $extracmd);
    foreach my $mode (keys %allmodes) {
        Irssi::print("key = '$mode':".$allmodes{$mode});
        if ($mode eq "k") {
            if ($allmodes{$mode} eq '+') {
                next if ($newkey eq "");
                if ($oldkey ne "") {
                    # we need to get rid of old key too
                    $modecmd .= "-k";
                    $extracmd .= " $oldkey";
                }
                $extracmd .= " $newkey";
            } else {
                $extracmd .= " $oldkey";
            }
        }
        if ($mode eq "l" && $allmodes{$mode} eq '+') {
            next if ($limit <= 0);
                        $extracmd .= " $limit";
        }
        $modecmd .= $allmodes{$mode}.$mode;
    }

    if ($modecmd ne "") {
        $channel->{server}->command("/mode $channame $modecmd$extracmd");
    }
}

sub mlock_mode_changed {
    my ($server, $data) = @_;
    my ($channel, $mode) = split(/ /, $data, 2);

    mlock_check_mode($server, $channel);
}

sub mlock_synced {
    my $channel = $_[0];

    mlock_check_mode($channel->{server}, $channel->{name});
}

Irssi::command_bind('mlock', 'cmd_mlock');
Irssi::signal_add_last("event mode", "mlock_mode_changed");
Irssi::signal_add("channel synced", "mlock_synced");