# Search and select windows similar to ido-mode for emacs
#
# INSTALL:
#
# This script requires that you have first installed and loaded 'uberprompt.pl'
# Uberprompt can be downloaded from:
#
# http://github.com/shabble/irssi-scripts/raw/master/prompt_info/uberprompt.pl
#
# and follow the instructions at the top of that file for installation.
#
# USAGE:
#
# * Setup: /bind ^R /history_search_start
#
# * Then type ctrl-R and type what you're searching for
#
# * You can cycle through multiple matches with ^R (older matches), and
#   ^S (newer matches)
#
# Based in part on window_switcher.pl script Copyright 2007 Wouter Coekaerts
# <coekie@irssi.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

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

use vars qw($VERSION %IRSSI);
$VERSION = '2.0';
%IRSSI =
  (
   authors     => 'Tom Feist, Wouter Coekaerts',
   contact     => 'shabble+irssi@metavore.org, shabble@#irssi/freenode',
   name        => 'rl_history_search',
   description => 'Search within your typed history as you type'
                . ' (like ctrl-R in readline applications)',
   license     => 'GPLv2 or later',
   url         => 'http://github.com/shabble/irssi-scripts/tree/master/history-search/',
   changed     => '24/7/2010'
  );


# TODO:
# C-g - cancel
# C-spc - narrow
# flex matching (on by default, but optional)
# server/network narrowing
# colourised output (via uberprompt)
# C-r / C-s rotate matches


my $search_str = '';
my $search_active = 0;

my @history_cache  = ();
my @search_matches = ();
my $match_index = 0;


my $DEBUG_ENABLED = 0;
sub DEBUG () { $DEBUG_ENABLED }

# check we have uberprompt loaded.

sub script_is_loaded {
    my $name = shift;
    print "Checking if $name is loaded" if DEBUG;
    no strict 'refs';
    my $retval = defined %{ "Irssi::Script::${name}::" };
    use strict 'refs';

    return $retval;
}

unless (script_is_loaded('uberprompt')) {
    print "This script requires 'uberprompt.pl' in order to work. "
      . "Attempting to load it now...";
    Irssi::signal_add('script error', \&load_uberprompt_failed);
    Irssi::command("script load uberprompt.pl");
    unless(script_is_loaded('uberprompt')) {
        load_uberprompt_failed("File does not exist");
    }
    history_init();
}

sub load_uberprompt_failed {
    Irssi::signal_remove('script error', \&load_prompt_failed);
    print "Script could not be loaded. Script cannot continue. "
      . "Check you have uberprompt.pl installed in your path and "
        .  "try again.";
    die "Script Load Failed: " . join(" ", @_);
}

sub history_init {
    Irssi::settings_add_bool('history_search', 'histsearch_debug', 0);

    Irssi::command_bind('history_search_start', \&history_search);

    Irssi::signal_add      ('setup changed'   => \&setup_changed);
    Irssi::signal_add_first('gui key pressed' => \&handle_keypress);

    setup_changed();
}

sub setup_changed {
    $DEBUG_ENABLED = Irssi::settings_get_bool('histsearch_debug');
}


sub history_search {
    $search_active = 1;
    $search_str = '';
    $match_index = -1;

    @history_cache = Irssi::active_win()->get_history_lines();
    @search_matches = ();

    update_history_prompt();
}

sub history_exit {
    $search_active = 0;
    Irssi::signal_emit('change prompt', '', 'UP_INNER');
}

sub update_history_prompt {
    my $col = scalar(@search_matches) ? '%g' : '%r';
    Irssi::signal_emit('change prompt',
                       ' reverse-i-search: `' . $col . $search_str
                       . '%n' . "'",
                       'UP_INNER');
}

sub update_history_matches {
    my ($match_str) = @_;
    $match_str = $search_str unless defined $match_str;

    my %unique;
    my @matches = grep { m/\Q$match_str/i } @history_cache;

    @search_matches = ();

    # uniquify the results, whilst maintaining order.
    foreach my $m (@matches) {
        unless (exists($unique{$m})) {
            # add them in reverse order.
            unshift @search_matches, $m;
        }
        $unique{$m}++;
    }

    print "updated matches: ", scalar(@search_matches), " ",
      join(", ", @search_matches) if DEBUG;
}

sub get_history_match {
    return $search_matches[$match_index];
}

sub prev_match {

    $match_index++;
    if ($match_index > $#search_matches) {
        $match_index = 0;
    }
    print "index now: $match_index" if DEBUG;
}

sub next_match {

    $match_index--;
    if ($match_index < 0) {
        $match_index = $#search_matches;
    }
    print "index now: $match_index" if DEBUG;
}

sub update_input {
    my $match = get_history_match();
    Irssi::gui_input_set($match);
	Irssi::gui_input_set_pos(length $match);
}

sub handle_keypress {
	my ($key) = @_;

    return unless $search_active;

	if ($key == 10) { # enter
        print "selecting history and quitting" if DEBUG;
        history_exit();
        return;
	}

    if ($key == 18) { # Ctrl-R
        print "skipping to prev match" if DEBUG;
        prev_match();
        update_input();
        update_history_prompt();
        Irssi::signal_stop(); # prevent the bind from being re-triggered.
        return;
    }

    if ($key == 19) { # Ctrl-S
        print "skipping to next match" if DEBUG;
        next_match();
        update_input();
        update_history_prompt();

        Irssi::signal_stop();
        return;
    }

    if ($key == 7) { # Ctrl-G
        print "aborting search" if DEBUG;
        history_exit();

        # cancel empties the inputline.
        Irssi::gui_input_set('');
        Irssi::gui_input_set_pos(0);

        Irssi::signal_stop();
        return;
    }

    if ($key == 127) { # DEL

        if (length $search_str) {
            $search_str = substr($search_str, 0, -1);
            print "Deleting char, now: $search_str" if DEBUG;
        }
        update_history_matches();
        update_history_prompt();
        update_input();

        Irssi::signal_stop();
        return;
    }

    # TODO: handle esc- sequences and arrow-keys?

    if ($key >= 32) { # printable
        $search_str .= chr($key);

        update_history_matches();
        update_history_prompt();
        update_input();

        Irssi::signal_stop();
        return;
    }

    # any other key exits, for now.
    history_exit();
    #Irssi::signal_stop();
}