#!/usr/bin/perl -w

# tkx-ed - Simple text editor

use strict;

use Tkx;
use File::Basename qw(basename);

(my $PROGNAME = $0) =~ s,.*[\\/],,;
my $IS_AQUA = Tkx::tk_windowingsystem() eq "aqua";

Tkx::package_require("BWidget");

eval {
    Tkx::package_require("style");
    Tkx::style__use("as", -priority => 70);
};
if ($@) {
    $@ =~ s/ at .*//;
    warn "Using plain look: $@";
}

# state
my $file = "";

# set up main window
my $mw = Tkx::widget->new(".");
my $sw = $mw->new_ScrolledWindow();
$sw->g_pack(
    -fill => "both",
    -expand => 1,
);

my($t, $tw);
eval {
    Tkx::package_require("ctext");
    # A ctext's true text widget is a subwidget
    $t = $sw->new_ctext();
    $tw = $t->_kid("t");
};
if ($@) {
    # fallback is the standard widget
    $@ =~ s/ at .*//;
    warn "Using plain text: $@";
    $t = $sw->new_text();
    $tw = $t;
}
$t->configure(
    -bd => 1,
    -undo => 1,
    -wrap => "none",
);

$sw->setwidget($t);

$mw->configure(-menu => mk_menu($mw));

if (@ARGV) {
    Tkx::after_idle([\&load, $ARGV[0]])
}
else {
    new();
}

Tkx::MainLoop();
exit;

sub mk_menu {
    my $mw = shift;
    Tkx::option_add("*Menu.tearOff", 0);
    my $m = $mw->new_menu();
    my $fm = $m->new_menu();
    my $em = $m->new_menu();
    my $hm = $m->new_menu();

    my $control = ($^O eq "darwin") ? "Command" : "Control";
    my $ctrl    = ($^O eq "darwin") ? "Command-" : "Ctrl+";

    $m->add_cascade(
	-label => "File",
	-menu => $fm,
    );
    $m->add_cascade(
	-label => "Edit",
	-menu => $em,
    );
    $m->add_cascade(
	-label => "Help",
	-menu => $hm,
    );

    # File menu
    $fm->add_command(
        -label => "New",
	-accelerator => $ctrl . "N",
        -command => \&new,
    );
    Tkx::bind("all", "<$control-n>", \&new);
    $fm->add_command(
        -label => "Open...",
	-accelerator => $ctrl . "O",
        -command => \&my_open,
    );
    Tkx::bind("all", "<$control-o>", \&my_open);
    $fm->add_command(
        -label => "Save",
	-accelerator => $ctrl . "S",
        -command => \&save,
    );
    Tkx::bind("all", "<$control-s>", \&save);
    $fm->add_command(
        -label => "Save As...",
        -command => \&save_as,
    );
    unless ($IS_AQUA) {
	$fm->add_command(
	    -label => "Exit",
	    -underline => 1,
	    -accelerator => $ctrl . "Q",
	    -command => [\&Tkx::destroy, $mw],
	    );
	Tkx::bind("all", "<$control-q>", [\&Tkx::destroy, $mw]);
    }

    # Edit menu
    $em->add_command(
	-label => "Cut",
	-command => [\&Tkx::event_generate, $tw, "<<Cut>>"]
    );
    $em->add_command(
	-label => "Copy",
	-command => [\&Tkx::event_generate, $tw, "<<Copy>>"],
    );
    $em->add_command(
	-label => "Paste",
	-command => [\&Tkx::event_generate, $tw, "<<Paste>>"],
    );

    # Help menu

    $hm->add_command(
        -label => "View $PROGNAME source",
        -command => sub { load(__FILE__) },
    );

    my $about_menu = $hm;
    if ($IS_AQUA) {
	# On Mac OS we want about box to appear in the application
	# menu.  Anything added to a menu with the name "apple" will
	# appear in this menu.
    	$about_menu = $m->new_menu(
	    -name => "apple",
    	);
    	$m->add_cascade(
    	     -menu => $about_menu,
    	);
    }
    $about_menu->add_command(
	-label => "About $PROGNAME",
        -command => sub {
	    Tkx::tk___messageBox(
	        -parent => $mw,
                -title => "About \u$PROGNAME",
                -type => "ok",
                -icon => "info",
                -message => "$PROGNAME v$Tkx::VERSION\n" .
                            "Copyright 2005 ActiveState. " .
                            "All rights reserved.",
            );
        },
    );

    return $m;
}

sub new {
    $t->delete("1.0", "end");
    set_file("");
}

sub my_open {
    my $f = Tkx::tk___getOpenFile(
        -parent => $mw,
    );
    load($f) if length $f;
}

sub load {
    my $f = shift;
    open(my $fh, "<:utf8", $f) || die "Can't open '$file': $!";
    $t->delete("1.0", "end");
    $t->insert("end", scalar do { local $/; <$fh> });
    set_file($f);
}

sub set_file {
    $file = shift;
    update_title();
}

sub save {
    return save_as() unless length $file;
    _save($file);
}

sub save_as {
    my $f = Tkx::tk___getSaveFile(
        -parent => $mw,
    );
    if (length $f) {
        _save($f);
        set_file($f);
    }
}

sub _save {
    my $f = shift;
    open(my $fh, ">", $f) || die "Can't open '$file': $!";
    print $fh $t->get("1.0", "end - 1 char");
    close($fh) || die "Can't write '$file': $!";
}

sub update_title {
    my $title;
    if (length $file) {
	$title = basename($file);
    }
    else {
	$title = "<no name>";
    }
    $title .= " - " . basename($0);
    $mw->g_wm_title($title);
}

__END__

=head1 NAME

tkx-ed - Simple editor

=head1 SYNOPSIS

 tkx-ed [<file>]

=head1 DESCRIPTION

The F<tkx-ed> program is a simple text editor implemented with the
C<Tkx> toolkit.  Its main purpose is to demonstrate how this kind of
application is written, so please take a look at its source code.

When the editor starts up it shows a blank page where you can start
entering text directly.

If a file name is passed on the command line then the editor will
visit this file initially.

=head1 LICENSE

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

Copyright 2005 ActiveState.  All rights reserved.

=head1 SEE ALSO

L<Tkx>