#!/usr/bin/perl -w

# get web page using curl and parse for temperature data
$homepage = 'output';
$val1 = 0;
$val2 = 0;
$val3 = 0;
$val4 = 0;

while (1)
{
  system "curl -s http://drizzl.uml.edu/htbin/obs > $homepage";

  open (INPU, $homepage) or die "cannot open output file";
  $result = join(":", <INPU>);

  # can modify later for negative temperatures
  if ($result =~ /Temperature \s+ ([0-9]+\.[0-9]+)/i)
    {
      $val2 = $1;
      printf "\nOld temperature is $val1 degrees F";
      printf "\nNew temperature is $val2 degrees F\n";
   }
  else
    {
      printf "\nTemperature not found\n";
    }
  close (INPU) or die "cannot close output file";

  # calculate the change in temperature, temperature directionality
  $val3 = ($val2-$val1);
  if (($val3 >= 0) && ($val4 == 0)){
    # do nothing
  }
  elsif (($val3 > 0) && ($val4 == 1)){
    $val4 = 0;
    system "../swr 6";
  }
  elsif (($val3 <= 0) && ($val4 == 1)){
    # do nothing
  }
  else {
    $val4 = 1;
    system "../swr 6";
  }

  $val1 = $val2;
  sleep(10);
}