# tk_centered_frame_3.pl                                    28may19waw

use strict;
use warnings;

use Tk;
use Tk::ProgressBar;

my %Contents = (  # various fake content
    percent => [ 0, 1, 50, 90, 100, 120, ],
    message => [  # user messages
        'msg 1',
        'user msg 2',
        'user message 3 (50%)',
        'user message four (90%)',
        'user message five (100 percent)',
        'really long user message six (120 percent progress)',
        ],
    );
die "fake messages and percentages don't match"
    if @{ $Contents{message} } != @{ $Contents{percent} };

my $MW = MainWindow->new();

my $StatusBar = $MW->Frame()
    ->pack(qw(-side top  -expand 1  -fill x));

use constant STATUS_SUBFRAME_PACK => qw(-side left  -expand 1  -fill x);

# define 3 sub-frames in status bar frame.

use constant PAGING_SUBFIELD_WIDTH => 9;
use constant STATUS_SUBFRAME_WIDTH => PAGING_SUBFIELD_WIDTH * 3;

my $UserMessage = "UNDEFINED user message";
my $msg = $StatusBar->Label(
    -anchor       => 'w',
    -relief       => 'flat',
    -width        => STATUS_SUBFRAME_WIDTH,
    -textvariable => \$UserMessage,
    )->pack(STATUS_SUBFRAME_PACK);

my $paging = $StatusBar->Frame()  # to be filled with sub-frames
    ->pack(STATUS_SUBFRAME_PACK);

my $percent_done = undef;
my $progress = $StatusBar->ProgressBar(
    -width => STATUS_SUBFRAME_WIDTH,
    -length => 200,
  # -length => STATUS_SUBFRAME_WIDTH,
    -anchor => 'w',
    -from => 0,
    -to => 100,
    -blocks => 1,
    -colors => [ 0 => '#93ff66',  50 => '#ffff66',  80 => '#dc143c', ],
    -variable => \$percent_done
    )->pack(STATUS_SUBFRAME_PACK);

# define 3 sub-frames for paging buttons.

use constant PAGING_BUTTONS_PACK => qw(-side left  -expand 1  -fill both  -anchor center);

my $ButtonPagingPrevious = $paging->Button(
    -text    => '< Previous',
    -width   => PAGING_SUBFIELD_WIDTH,
    -command => \&dec_i_content,
    )->pack(PAGING_BUTTONS_PACK);

my $PagingMessage = 'UNDEFINED paging';
my $WidgetShowPaging = $paging->Label(
    -relief       => 'flat',
    -width        => PAGING_SUBFIELD_WIDTH,
    -textvariable => \$PagingMessage,
    )->pack(PAGING_BUTTONS_PACK);

my $ButtonPagingNext = $paging->Button(
    -text    => 'Next >',
    -width   => PAGING_SUBFIELD_WIDTH,
    -command => \&inc_i_content,
    )->pack(PAGING_BUTTONS_PACK);

init_fake_content();

$MW->MainLoop();

exit;

# subroutines ######################################################

{  # begin closure for faking various content

my $i_content = 0;

sub init_fake_content {
    $i_content = @_ ? shift : 0;
    update_user_msg_and_progress($i_content);
    update_paging_msg($i_content);
    }

sub inc_i_content {
    ++$i_content;
    $i_content = 0 if $i_content > $#{ $Contents{percent} };
    update_user_msg_and_progress($i_content);
    update_paging_msg($i_content);
    }

sub dec_i_content {
    --$i_content;
    $i_content = $#{ $Contents{percent} } if $i_content < 0;
    update_user_msg_and_progress($i_content);
    update_paging_msg($i_content);
    }

sub update_user_msg_and_progress {
    my $i = shift;
    $percent_done = $Contents{percent}[$i];
    $UserMessage  = $Contents{message}[$i];
    }

sub update_paging_msg {
    my $i = shift;
    $PagingMessage =
        sprintf '%d of %d', 1+$i, scalar @{ $Contents{message} };
    }

}  # end closure for faking various content