#!/usr/bin/env perl

use strict;
use warnings;
use constant {
    DB_DELAY => 2000,
    RESULTS_SEPARATOR => '=' x 40 . "\n",
};

use Tk;
use Tk::ProgressBar;

{
    my $mw = MainWindow::->new();
    sub _mw () { $mw }

    my ($progress_bar, $progress, $results);
    sub _progress_bar () { \$progress_bar }
    sub _progress () { \$progress }
    sub _results () { \$results }
}

{
    my $search_F = _mw->Frame->pack;
    $search_F->Label(
        -text => 'Search:',
    )->pack(-side => 'left');
    $search_F->Entry(
        -validate => 'key',
        -validatecommand => \&run_query,
    )->pack(-side => 'left');
    $search_F->Label(
        -text => 'Progress:',
    )->pack(-side => 'left');
    ${+_progress} = 0;
    ${+_progress_bar} = $search_F->ProgressBar(
        -variable => _progress,
        -from => 0,
        -to => 100,
        -blocks => 10,
        -gap => 0,
        -colors => [ 0 => '#99ccff' ],
        -width => 20,
        -length => 200,
    )->pack(-side => 'left');
    $search_F->Button(
        -text => 'Exit',
        -command => sub { exit },
    )->pack(-side => 'left');

    my $results_F = _mw->Frame->pack;
    ${+_results} = $results_F->Scrolled('Text',
        -scrollbars => 'osoe',
    )->pack;
}

MainLoop;

sub run_query {
    my ($query) = @_;

    if (length $query) {
        ${+_results}->insert(end => "Query: $query\n");
        ${+_results}->insert(end => "Results:\n");

        for (@{get_results($query)}) {
            ${+_results}->insert(end => "$_\n");
        }

        ${+_results}->insert(end => RESULTS_SEPARATOR);
        ${+_results}->yviewMoveto(1);
    }

    return 1;
}

{
    my @data; INIT { @data = qw{q qwe qwerty a asd asdfgh} }
    my %cache;

    sub get_results {
        my ($query) = @_;

        unless (exists $cache{$query}) {
            $cache{$query} = [ grep /\Q$query/, @data ];

            my $step = int 0.5 + DB_DELAY / 10;

            for (my $i = 0; $i <= DB_DELAY; $i += $step) {
                _mw->after($step);
                ${+_progress} = $i / DB_DELAY * 100;
                ${+_progress_bar}->idletasks;
            }

            ${+_progress} = 0;
        }

        return $cache{$query};
    }
}