#!/usr/bin/perl
#
# -*- perl -*- (this line is for emacs)
#
# Pikture
# Xterm/Ascii art drawing program
# Written by X-3mE'89 - http://exxtreme.altervista.org
# Released under GNU GPL terms
#
# Big thanks to Alessandro Rubini, author of GPM,
# that inspired this code
#

use strict;
use warnings;

use Term::ReadKey;
use Term::Size;
use Term::ReadLine;

#
# Escape sequences for Xterm mouse handling
# (DEC private mode set/reset)
#

my $Dec_Pvt_Mode_Set = "h";         # DEC private mode set
my $Dec_Pvt_Mode_Reset = "l";       # DEC private mode unset

my $VT200_Mouse = "1000";           # DEC pvt mode for VT200 mouse
my $VT200_HighLight_Mouse = "1001"; # DEC pvt mode for VT200 hilite mouse
my $Btn_Event_Mouse = "1002";       # DEC pvt mode: detect button events
my $Any_Event_Mouse = "1003";       # DEC pvt mode: detect any mouse event

my %MouseState;
$MouseState{'x'}      = 0;          # mouse X
$MouseState{'y'}      = 0;          # mouse Y
$MouseState{'mod'}    = 0;          # mode (pressed/released)
$MouseState{'btn'}    = 0;          # button
$MouseState{'wheel'}  = 0;          # was wheel moved?
$MouseState{'moving'} = 0;          # detect mouse motion

my $PenChar = '+';

my $Columns = 0;
my $Lines = 0;
my @Screen = undef;

# Raw mode. I chose to put this in a variable for debugging.
my $Read_Mode = 4;

#
# DecSet
# Accepts a list of modes and prints escape sequences that set the
# associate DEC private mode
#

sub DecSet
{
	my $what = shift;
	print "\e[?".$what.$Dec_Pvt_Mode_Set;
}

#
# DecUnset
# Accepts a list of modes and prints escape sequences that reset the
# associate DEC private mode
#

sub DecUnset
{
	my $what = shift;
	print "\e[?".$what.$Dec_Pvt_Mode_Reset;
}

sub InitScr
{
	print "\ec";
	ReadMode $Read_Mode;
	DecSet $VT200_Mouse;
	#DecSet $VT200_HighLight_Mouse;
	DecSet $Btn_Event_Mouse;
	DecSet $Any_Event_Mouse;
	($Columns, $Lines) = Term::Size::chars *STDOUT{IO};
}

sub EndScr
{
	print "\n";
	DecUnset $VT200_Mouse;
	#DecUnset $VT200_HighLight_Mouse;
	DecUnset $Btn_Event_Mouse;
	DecUnset $Any_Event_Mouse;
	print "\ec";
	ReadMode 0;
}

sub BeginMouse
{
	DecSet $VT200_Mouse;
	DecSet $Btn_Event_Mouse;
	DecSet $Any_Event_Mouse;
}

sub EndMouse
{
	DecUnset $VT200_Mouse;
	DecUnset $Btn_Event_Mouse;
	DecUnset $Any_Event_Mouse;
}

#
# Paint
# Paints on the screen.
#

sub Paint
{
	if($MouseState{'btn'} == 0)
	{
		print "\e[".$MouseState{'y'}.";".$MouseState{'x'}."H".
			$PenChar;
		print "\e[0;0H";
		$Screen[$MouseState{'y'}][$MouseState{'x'}-1] = $PenChar;
	}
}

#
# HandleChars
# Handle input chars != mouse events
#

sub HandleChars
{
	my $char = chr shift;
	if(($char eq 'p') or ($char eq 'P'))
	{
		ReadMode 0;
		EndMouse;
		print "\e[";
		print $Lines-2;
		print ";0HPen char: ";
		$PenChar = ReadKey;
		ReadMode $Read_Mode;
		BeginMouse;
		print "\e[".($Lines-2).";0H";
		for(my $i = 0; $i < $Columns; $i++)
		{
			print " ";
		}
		print "\e[".($Lines-2).";0H";
	}
	if(($char eq 'c') or ($char eq 'C'))
	{
		InitScr;
		my ($i,$j);
		for($i = 0; $i < $Lines; $i++)
		{
			for($j = 0; $j < $Columns; $j++)
			{
				$Screen[$i][$j] = " ";
			}
		}
	}
	if(($char eq 'r') or ($char eq 'R'))
	{
		InitScr;
		my ($i, $j);
		for($i = 0; $i < $Lines; $i++)
		{
			for($j = 0; $j < $Columns; $j++)
			{
				print $Screen[$i][$j];
			}
			my $real = $i + 1;
			print "\e[$real;0H";
		}
	}
	if(($char eq 's') or ($char eq 'S'))
	{
		ReadMode 0;
		EndMouse;
		print "\e[";
		print $Lines-2;
		print ";0HFile name: ";
		my $Fname = ReadLine;
		ReadMode $Read_Mode;
		BeginMouse;
		print "\e[".($Lines-2).";0H";
		for(my $i = 0; $i < $Columns; $i++)
		{
			print " ";
		}
		print "\e[";
		print $Lines-1;
		print "0H";

		open(FILE, ">$Fname") or die "Couldn't open $Fname: $!\n";

		my ($i, $j);
		for($i = 0; $i < $Lines; $i++)
		{
			for($j = 0; $j < $Columns; $j++)
			{
				print FILE $Screen[$i][$j];
			}
			print FILE "\n";
		}

		close FILE;
		ReadMode $Read_Mode;
		BeginMouse;
	}
}

#
# MouseEvents
# Handle mouse events, and put the result in %MouseEvents.
#

sub MouseEvents
{
	my $btn = ord(ReadKey) - 32;
	my $mod = $btn & 28;	# get other 3 bits  (mask = 00011100)
	$mod >>= 3;		# shift 3 bits right
	my $wheel = 0;
	my $moving = 0;

	if($mod != 0)
	{
		$btn &= ~28;	# remove modifier info
	}
	
	if($btn >= 64)          # ... then wheel has been rolled
	{
		$wheel = 1;
		$btn -= 64;
	}
	elsif($btn >= 32)       # ... then mouse has been moved
	{
		$moving = 1;
		$btn -= 32;
	}
	
	my $x = ord(ReadKey) - 32;
	my $y = ord(ReadKey) - 32;

	#
	# Fill %MouseState's fields
	#

	$MouseState{'x'} = $x;
	$MouseState{'y'} = $y;
	$MouseState{'mod'} = $mod;
	$MouseState{'btn'} = $btn;
	$MouseState{'wheel'} = $wheel;
	$MouseState{'moving'} = $moving;

	printf "\e[0;0H[P]en - [C]lear - [R]efresh - [Q]uit\n".
		"\e[".($Lines-1).";0HBtn=%3d; X=%3d; Y=%3d; Mod=%3d; ".
		"Wheel=%3d; Moving=%3d",
		$btn, $x, $y, $mod, $wheel, $moving;

	Paint;
}

################## ###  ##   #
#
# Main loop
#
################## ###  ##   #

#
# Clear screen and set read mode to $Read_Mode
#

InitScr;

my ($i,$j);
for($i = 0; $i < $Lines; $i++)
{
	for($j = 0; $j < $Columns; $j++)
	{
		$Screen[$i][$j] = " ";
	}
}

my $key = "";

$| = 1; # autoflush

while(($key = ReadKey) ne 'q')
{
	my $code = ord $key;
	if($code == 0x1b)	# got an escape seq ("\e")
	{
		# is it 0x5b ([) ?
		$key = ReadKey;
		$code = ord($key);
		next if($code != 0x5b);	# 0x5b = '['
		my $what = ord(ReadKey);
		if($what == 0x4d)	# 0x4d = 'M'
		{
			MouseEvents;
		}
	}
	else
	{
		HandleChars($code)
	}
}

EndScr;
ReadMode 0;