#! /usr/bin/perl
#############################################################################
# Program Description/Comments/Updates
#############################################################################
# Quip.pl by Leslie Houk
# 
# SYNTAX: quip.pl [<filename>] [/?|-?|/h|/help|-h|-help|--help]
# 
# DESCRIPTION: Reads a text file of one-line quips and randomly displays
#              one of them in an xmessage box.
# 
# PARAMETERS: <filename>: Specifies the input file of quips.
#
#             /?, etc.: Displays this help file.
#             
#############################################################################
 
#############################################################################
# Defaults
#############################################################################
$quip_file = $ENV{ 'HOME' } . '/data/quip.dat';
$font = '-misc-fixed-medium-r-normal--20-140-100-100-c-100-iso8859-1';
$def_x = 200;
$def_y = 300;
 
#############################################################################
# Main body
#############################################################################
foreach $i ( 0 .. $#ARGV )
{
	$ARGV[$i] =~ tr/A-Z/a-z/;
	if ( $ARGV[$i] eq '-?' || $ARGV[$i] eq '/?' || $ARGV[$i] eq '/help' ||
		$ARGV[$i] eq '/h' || $ARGV[$i] eq '-help' || $ARGV[$i] eq '-h' ||
		$ARGV[$i] eq '--help' )
	{
		print( "Quip.pl Version 1.0 by Leslie Houk.\n\n" );
		print( "SYNTAX: quip.pl [<filename>] [/?|-?|/h|/help|-h|-help|--help]\n\n" );
		print( "DESCRIPTION: Reads a text file of one-line quips and randomly displays\n" );
		print( "             one of them in an xmessage box.\n\n" );
		print( "PARAMETERS: <filename>: Specifies the input file of quips.  The\n" );
		print( "                        default is \"$quip_file\".\n\n" );
		print( "            /?, -?, /h, etc.: Displays this help file.\n\n" );

		exit;
	}
	else
	{
		$quip_file = $ARGV[$i];
	}
}

open( QUIPS, "< $quip_file" ) ||
	die "Can not find file \"$quip_file\" - aborting";

#############################################################################
# This algorithm is taken from the O'Reilly book "Programming perl" by
# Larry Wall and Randal L. Schwartz, Chapter 5: Common Tasks With Perl,
# Section: Selecting A Random Line From A File.  Quoting from the book:
#
#     "This procedure selects a line at random from a file, using
#     just one pass over the file and without knowing in advance
#     the number of lines.  It works by calculating the probability
#     that the current line (indicated by the $. variable) would
#     be selected if this line were the last line in the file.  The
#     first line is selected with a probability of 100%, but the
#     second line has a 50% change of replacing the first one, the
#     third line a 33% chance of replacing one of the first two,
#     and so on."
#############################################################################
srand;
while ( <QUIPS> )
{
	if ( rand( $. ) < 1.0 )
	{
		$line = $.;
		$quip = $_;
	}
}

$quip =~ tr/\n\r//d;
close( QUIPS );

#############################################################################
# All this is to get the xmessage box centered.  "xdpyinfo" is used to get
# the size of the display.  The formulas used to get $x and $y are based
# on the default font; if you use another one, you may have to tweak them.
#############################################################################
open( XDPY, "xdpyinfo | " );
while ( <XDPY> )
{
	next if ! /dimensions:/;
	s/^.*dimensions: *//;
	s/ *pixels.*$//;
	tr/\n\r//d;
	@dimen = split( /x/ );
	last;
}
close( XDPY );
# print( "dimen[0]: $dimen[0]  dimen[1]: $dimen[1]\n" );
$dimen[0] = ( $dimen[0] / 2 ) - ((( length( $quip ) * 10 ) + 14 ) / 2 );
$dimen[1] = ( $dimen[1] / 2 ) - 36;
$x = ( $dimen[0] > 0 ) ? $dimen[0] : $def_x;
$y = ( $dimen[1] > 0 ) ? $dimen[1] : $def_y;

exec( "xmessage -title 'Quip.pl (click to dismiss)' " .
	"-name 'Quip.pl' -buttons '' " .
	"-xrm \"Xmessage.geometry: +$x+$y\" " .
	"-xrm \"Xmessage*Font: $font\" " .
	"-xrm '*message.borderWidth: 0' " .
	"-xrm '*Translations: #override <BtnDown>: exit(0)' " .
	"\"Quip #$line:\n\n$quip\"" );
exit;