#!/usr/bin/env perl
# easytag.wrapper - Launcher for "easytag" main program
# License:  Creative Commons Attribution-NonCommercial-ShareAlike 2.5
# Revision: 071016

# Note:  The license indicated above applies to this file.  It doesn't
# apply to the official EasyTAG package,  or to any  file derived from
# that package.

#---------------------------------------------------------------------
#                         license information
#---------------------------------------------------------------------

# This section may not be modified except as approved by the author or
# licensor, or to make non-content changes such as adjustments to par-
# agraph formatting or white space.

# This  version of this software is  distributed  under  the following
# license:
#
#       Creative Commons Attribution-NonCommercial-ShareAlike 2.5

# You may use, modify, and redistribute this software without fees  or
# royalties, but only under the terms and conditions set forth  by the
# license.  In particular, copies and derived works cannot be used for
# commercial purposes.  Additionally, the license propagates to copies
# and derived works. Furthermore, you must provide attribution "in the
# manner  specified  by the  author or licensor".  The latter point is
# discussed below.

# The author [and licensor] hereby specifies that  attribution must be
# handled in the following manner:  a. If the software is interactive,
# any  About or Credits dialog boxes, windows, or output text provided
# by the  original version must be preserved and readily accessible to
# the end user at runtime.  b. If the software is non-interactive,  or
# if it does not  provide  About or Credits dialog boxes, windows,  or
# output text,  the  operating system and/or  desktop environment used
# must provide attribution that is  visible and/or  readily accessible
# to the end user at runtime.

# The following techniques  do not meet the  attribution requirements:
# Attribution through text files,  attribution  through  printed docu-
# mentation,  verbal attribution,  or postings on  external  web sites
# [i.e.,  web  sites that are not  an intrinsic local component of the
# operating system or  desktop environment used].  These  examples are
# provided for illustrative purposes only.

# It should be noted that trademarks are an additional issue.  If this
# software  uses any  trademarks,  trademark-related  restrictions may
# apply.

# This is not a  complete explanation of the  terms and conditions in-
# volved.  For more information, see the Creative Commons Attribution-
# NonCommercial-ShareAlike 2.5 license.

#---------------------------------------------------------------------
#                           important note
#---------------------------------------------------------------------

# This software is provided on an  AS IS basis with ABSOLUTELY NO WAR-
# RANTY.  The  entire risk as to the  quality and  performance of  the
# software is with you.  Should the software prove defective,  you as-
# sume the cost of all necessary  servicing, repair or correction.  In
# no event will any of the developers,  or any other party, be  liable
# to anyone for damages arising out of use of the software, or inabil-
# ity to use the software.

#---------------------------------------------------------------------
#                             explanation
#---------------------------------------------------------------------

# 1. Overview:

# This program [easytag.wrapper]  is a simple wrapper that starts  the
# main EasyTAG executable [which  must be  renamed to  "easytag.bin"].
# Presently, three features are implemented:
#
#     a. The wrapper tries to prevent multiple instances.
#
#     b. It displays an FYI dialog that warns the user about EasyTAG's
#        slow startup procedure.
#
#     c. Additionally,  the wrapper overrides  EasyTAG's geometry set-
#        tings [both the default settings and  the saved settings,  if
#        any].  In other words,  the wrapper determines the dimensions
#        and position of EasyTAG's  main  window.  This fixes problems
#        that occur with some displays.

#---------------------------------------------------------------------

# 2. Requirements:

# At the GUI level,  this program requires  Perl 5, Perl-Gtk2, LACSUB,
# "zenity",  and a small utility named "getx11dim". Additionally, some
# versions of this program may require "glxinfo".

# These components  are standard,  except for  LACSUB and "getx11dim".
# You should be able to obtain  the  latter components from  the  same
# place as this file.  Note: "getx11dim" is distributed  under a  BSD-
# style license. LACSUB [like this file] is distributed  under a Crea-
# tive Commons license.

#---------------------------------------------------------------------
#                        standard module setup
#---------------------------------------------------------------------

require 5.6.1;
use strict;
use Carp;
use warnings;
                                # Trap warnings
$SIG {__WARN__} = sub { die @_; };

#---------------------------------------------------------------------
#                        add LACSUB module[s]
#---------------------------------------------------------------------

use LACSUB::GUI
 ( @LACSUB::GUI::EXPORT_OK );

#---------------------------------------------------------------------
#                           basic constants
#---------------------------------------------------------------------

use constant ZERO  => 0;        # Zero
use constant ONE   => 1;        # One

use constant FALSE => 0;        # Boolean FALSE
use constant TRUE  => 1;        # Boolean TRUE

#---------------------------------------------------------------------
#                         program parameters
#---------------------------------------------------------------------

my $DIR_BASE        = '__META_PREFIX__';
my $ALERT_ICON_PATH = "$DIR_BASE/misc/alert.png";
my $TARGET_PROGRAM  = "$DIR_BASE/bin/easytag.bin";

#---------------------------------------------------------------------
#                            main routine
#---------------------------------------------------------------------

sub Main
{
    my $data;                   # Data buffer
    my $n;                      # Scratch (integer)
    my $str;                    # Scratch (string )

#---------------------------------------------------------------------
# Verify that program isn't running.

    &VerifyNotRunning
    (
        -icon_path    => $ALERT_ICON_PATH                 ,
        -name         => 'easytag'                        ,
        -pattern_this =>
            ':\d\d\s(perl |)(\S+/|)easytag(|\.wrapper)\s' ,

        -pattern_next =>
            ':\d\d\s(perl |)(\S+/|)easytag\.bin\s'
    );

#---------------------------------------------------------------------
# Warn the user about EasyTAG's slow startup procedure.

    my $msg = << 'END';
EasyTAG scans the hard disk on startup. This may take a few minutes.
Do you want to proceed?
END
    my $cmd_dialog =  << "END";
zenity --question --title="Start EasyTAG" --text="$msg"
END

    $cmd_dialog =~ s@\s+\z@@s;
    $n = system $cmd_dialog;
    exit ONE if $n;

#---------------------------------------------------------------------
# Adjust configuration-file settings.

    my $HOME = $ENV {HOME};

    if (defined ($HOME) && length ($HOME) &&
        (-d $HOME) && (-r $HOME) && (-w $HOME) && (-x $HOME))
    {
        my $CFG_DIR  = "$HOME/.easytag";
        my $CFG_FILE = "$CFG_DIR/easytagrc";

        system "mkdir -p $CFG_DIR" unless -d $CFG_DIR;
        system "touch $CFG_FILE"   unless -f $CFG_FILE;

        $str = `getx11dim 2>&1`;
        $str = "" if !defined $str;
        my ($DisplayWidth, $DisplayHeight) = $str =~ m@^(\d+)x(\d+)@;

        if (defined ($DisplayHeight) && open (IFD, "<$CFG_FILE"))
        {
            undef $/;
            binmode IFD;
            $data = <IFD>;
            $data = "" if !defined $data;
            close IFD;

            my $main_x = 15;
            my $main_y = 70;
            my $main_w = $DisplayWidth  - 30;
            my $main_h = $DisplayHeight - ($main_y + 90);

            my $orig_data = $data;
            $data =~ s@\s*\z@\n@;
            my $EQWSZ = '[\011\040]*=[\011\040]*';

            if ($data !~ s@\b(main_window_width$EQWSZ)\d+@$1$main_w@)
            {
                $data .= "main_window_width=$main_w\n";
            }

            if ($data !~ s@\b(main_window_height$EQWSZ)\d+@$1$main_h@)
            {
                $data .= "main_window_height=$main_h\n";
            }

            if ($data !~ s@\b(main_window_x$EQWSZ)\d+@$1$main_x@)
            {
                $data .= "main_window_x=$main_x\n";
            }

            if ($data !~ s@\b(main_window_y$EQWSZ)\d+@$1$main_y@)
            {
                $data .= "main_window_y=$main_y\n";
            }

            if (($data ne $orig_data) && open (OFD, ">$CFG_FILE"))
            {
                print OFD $data;
                close OFD;
                print "Updated $CFG_FILE\n";
            }
        }
    }

#---------------------------------------------------------------------
# Wrap it up.

                                # Chain to target program
    exec $TARGET_PROGRAM, @ARGV;
    exit ONE;                   # Shouldn't be reached
}

#---------------------------------------------------------------------
#                            main program
#---------------------------------------------------------------------

&Main();                        # Call the main routine
exit ONE;                       # Shouldn't be reached