<?php

// -----
// Step 0: Configurize where your XML database is
// if this file doesn't exist then it will be created
$xml_db_loc = "pressures.xml";

// -----
// Step 1: Attempt to open XML database; if nonexistent, write a blank one in its location
global $dom, $pressures;
$dom = new DOMDocument;
if (file_exists($xml_db_loc)) {
	$dom->load($xml_db_loc);
	print $dom;
	exit;
	$pressures = $dom->item(0);
	$doc_contents = file_get_contents($xml_db_loc);
} else {
	$pressures = $dom->appendChild($dom->createElement('pressures'));
	$doc_contents = "";
}

// -----
// Step 2: Get your raw weather data
// most people will want to use the url
// $weather_data = file_get_contents("http://weather.noaa.gov/pub/data/observations/metar/stations/KSLN.TXT");
// for testing and debugging purposes we can use a local file, too
$weather_data = file_get_contents("./KSLN.TXT");

// -----
// Step 3: Figure out the time of the given data into happy fun UNIX epoch form
date_default_timezone_set("GMT");
$blammo = explode("\n", $weather_data);
$datetime = $blammo[0];
$timestamp = strtotime($datetime);

// -----
// Step 3.5: Check if this timestamp has already been done
if(preg_match("/" . $timestamp . "/", $doc_contents)) {
	exit();
}

// -----
// Step 4: Figure out what the pressure is
$data = $blammo[1];
$data_split = explode(" ", $data);
$the_data = false;
foreach($data_split as $thingy) {
	if(preg_match("/^A[0-9][0-9][0-9][0-9]$/", $thingy)) {
		$the_data = $thingy;
	}
	if($the_data) {
		break;
	}
}
$pressure_var = substr($the_data, 1, 4) / 100;

// -----
// Step 5: Throw it in the XML file and write
$pressure_tag = $dom->appendChild($pressures->createElement('pressure'));
$pressure_tag->setAttribute('timestamp', $timestamp);
$pressure_tag->setAttribute('pressure', $pressure_var);
$dom->formatOutput = true;
$dom->save($xml_db_loc);

?>