use strict;
use vars qw($VERSION %IRSSI);
use Storable;
use 5.014000;

use Irssi qw(command signal_add signal_add_first active_win
             settings_get_str settings_get_bool channels windows
             settings_add_str settings_add_bool get_irssi_dir
             window_find_refnum signal_stop);
$VERSION = '3.00';
%IRSSI = (
    authors     => 'Juerd',
    contact     => 'juerd@juerd.nl',
    name        => 'Scroll buffer restorer',
    description => 'Saves the buffer for /upgrade, so that no information is lost',
    license     => 'Public Domain',
    url         => 'http://juerd.nl/irssi/',
    changed     => 'Thu Mar 29 10:00 CEST 2018',
    changes     => 'Fixed file permissions (leaked everything via filesystem), rewritten to use Storable and print to correct levels',
    note1       => 'This script HAS TO BE in your scripts/autorun!',
    note2       => 'Perl support must be static or in startup',
);

# Q: How can I get a very smooth and clean upgrade?
#
# A: /set -clear upgrade_separator
#    /set upgrade_suppress_join ON (default)
#    /set channel_sync OFF

# Q: Can I use color in the upgrade_separator?
# Q: Is it possible to save my command history?
# Q: Can I prevent the screen from blinking?
# Q: Can you make it faster?
#
# A: Probably not, but if you can do it, tell me how.

use Irssi::TextUI;
use Data::Dumper;

my %suppress;

sub _filename { sprintf '%s/scrollbuffer', get_irssi_dir }

sub upgrade {
    my $out = { suppress => [ map $_->{server}->{address} . $_->{name}, channels ] };
    for my $window (windows) {
        next unless defined $window;
        next if $window->{name} eq 'status';
        my $view = $window->view;
        my $line = $view->get_lines;
        my $lines  = 0;
        my $buf = '';
        my $output;
        if (defined $line) {
            {
              push @$output, { level => $line->{info}{level}, data => $line->get_text(1) };
              $line = $line->next;
              redo if defined $line;
            }
        }
        push @{$out->{windows}}, { refnum => $window->{refnum}, lines => $output };
    }
    my $old_umask = umask 0077;
    my $fn = _filename;
    store($out, $fn) or die "Could not store data to $fn";
    umask $old_umask;
    unlink sprintf("%s/sessionconfig", get_irssi_dir);
    command 'layout save';
    command 'save';
}

sub restore {
    my $fn = _filename;
    my $in = retrieve($fn) or die "Could not retrieve data from $fn";
    unlink $fn or warn "unlink $fn: $!";
  
    my @suppress = @{$in->{suppress}};
    @suppress{@suppress} = (2) x @suppress if (settings_get_bool 'upgrade_suppress_join');
  
    active_win->command('^window scroll off');
    for my $win (@{$in->{windows}}) {
        my $window = window_find_refnum $win->{refnum};
        next unless $window;
        my @lines  = @{ $win->{lines} || [] };
        next unless @lines;
    
        my $view = $window->view;
        $view->remove_all_lines();
        $view->redraw();
        for my $line (@lines) {
            my $level = $line->{level};
            my $data  = $line->{data};
            $window->gui_printtext_after($window->last_line_insert, $level, "$data\n");
        }
        my $sep = settings_get_str 'upgrade_separator';
        $window->gui_printtext_after($window->last_line_insert, MSGLEVEL_CLIENTNOTICE, "\cO$sep\n") if $sep ne '';
        $view->redraw();
    }
    active_win->command('^window scroll on');
    active_win->command('^scrollback end');
}

sub suppress {
    my ($first, $second) = @_;
    return unless scalar keys %suppress and settings_get_bool 'upgrade_suppress_join';
    my $key_part = (grep { /^:?[#!+&]/ } split ' ', $second)[0];
    $key_part =~ s/^://;
    my $key = $first->{address} . $key_part;
    if (exists $suppress{$key} and $suppress{$key}--) {
        signal_stop();
        delete $suppress{$key} unless $suppress{$key};
    }
}

settings_add_str  'buffer', 'upgrade_separator'     => '=Upgrade=';
settings_add_bool 'buffer', 'upgrade_suppress_join' => 1;

signal_add_first 'session save'    => 'upgrade';
signal_add_first 'session restore' => 'restore';
signal_add       'event 366'       => 'suppress';
signal_add       'event join'      => 'suppress';

unless (-f sprintf('%s/scripts/autorun/buf.pl', get_irssi_dir)) {
    Irssi::print('PUT THIS SCRIPT IN ~/.irssi/scripts/autorun/ BEFORE /UPGRADING!!');
}

# Remove any left-over file. If 'session' doesn't exist (created by irssi
# during /UPGRADE), neither should our file.
unless (-e sprintf('%s/session', get_irssi_dir)) {
    my $fn = _filename;
    unlink $fn or warn "unlink $fn: $!" if -e $fn;
}