#! /usr/bin/perl
use strict;
use diagnostics;
use Tk;

#####################################################
# Stellt Temperaturen oder Zahlen aus einem         #
# einfachen Logfile grafisch in einer Kurve dar     #
#                                                   #
#    (c) Martin Holz <martin@martinholz.de>         #
#          http://www.perl-newbie.de                #
#####################################################

# Pfad zum Logfile
my $logfile = "/home/martin/.temperature.log";

# Zoom-Faktor
my $zoom = 2;

# Breite der Anzeige
my $graph_width = 10000;

# Logfile einlesen und in Arrays aufteilen ...
open (LOG, "<$logfile");
my @temperature_log = <LOG>;
close (LOG);

my (@max_temp, @min_temp, @akt_temp);

foreach (@temperature_log)
  {
    if ($_ =~ m/(\d\d\.\d) (\d\d\.\d) (\d\d\.\d)/i)
      {
	push (@max_temp, $1);
	push (@min_temp, $2);
	push (@akt_temp, $3);
      }
  }

# Jetzt wird gezeichnet
my $graph_window = MainWindow -> new;
$graph_window -> title ("TempWatch by Martin Holz \<martin\@martinholz.de\>");
my $button_bar = $graph_window -> Frame (-relief => 'raise') -> pack (-anchor => 'nw');
$button_bar -> Button (-text => 'Beenden', -command => sub {exit}) -> grid (-column => 0, -row => 0);
$button_bar -> Button (-text => 'Als PostScript speichern', -command => \&saveas) -> grid (-column => 1, -row => 0);

my $canvas = $graph_window -> Scrolled('Canvas') -> pack(-anchor => 'n');

my ($graph_max, $graph_min, $graph_akt, $v_scale, $v_scale_text);

my $v_zero = 200;
my $last_max_degree = 200;
my $last_min_degree = 200;
my $last_akt_degree = 200;
my $timestamp = 30;
my $last_timestamp = 30;

my $meridian = $canvas -> createLine(0,$v_zero,$graph_width,$v_zero);
my $meridian_text = $canvas -> createText(15,210, -text => "0°C");

# Legende
$canvas -> createLine(10,240,20,240, -fill => 'red');
$canvas -> createText(30,240, -text => "= maximale Temperatur", -anchor => 'w');
$canvas -> createLine(10,255,20,255, -fill => 'green');
$canvas -> createText(30,255, -text => "= minimale Temperatur", -anchor => 'w');
$canvas -> createLine(10,270,20,270, -fill => 'blue');
$canvas -> createText(30,270, -text => "= aktuelle Temperatur", -anchor => 'w');

for (my $i = 200 - (10*$zoom); $i > 0; $i = $i - (10*$zoom))
  {
    $v_scale = $canvas -> createLine(0,$i,$graph_width,$i, -fill => 'gray80');
    my $scale_degree = (200 - $i)/$zoom;
    $v_scale_text = $canvas -> createText(15,$i, -text => "$scale_degree°C");
  }

my $cnt = -1;
foreach (@akt_temp)
  {
    $cnt++;
    $timestamp = $timestamp+(10*$zoom);

    chomp $max_temp[$cnt];
    chomp $min_temp[$cnt];
    chomp $akt_temp[$cnt];

    my $max_degree = $max_temp[$cnt] * $zoom;
    $max_degree = $v_zero - $max_degree;

    my $min_degree = $min_temp[$cnt] * $zoom;
    $min_degree = $v_zero - $min_degree;

    my $akt_degree = $akt_temp[$cnt] * $zoom;
    $akt_degree = $v_zero - $akt_degree;

    # Kurven zeichnen ...
    $graph_max = $canvas -> createLine($last_timestamp,$last_max_degree,$timestamp,$max_degree,-fill => 'red');
    $graph_min = $canvas -> createLine($last_timestamp,$last_min_degree,$timestamp,$min_degree,-fill => 'green');
    $graph_akt = $canvas -> createLine($last_timestamp,$last_akt_degree,$timestamp,$akt_degree,-fill => 'blue');

    $last_max_degree = $max_degree;
    $last_min_degree = $min_degree;
    $last_akt_degree = $akt_degree;

    $last_timestamp = $timestamp;
  }
MainLoop;

sub saveas {
  my $save_file = $graph_window -> getSaveFile (
				-defaultextension => ".ps",
				-filetypes        => [['PostScript', '.ps'],],
				-initialfile => "temperatures_graph.ps",
			       );
  my $postscript = $canvas->postscript(-file => "$save_file");
}