<?php
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// weather.php

// copyright (c) 2009 drow <drow@bin.sh>
// this script is free to download, modify, and use
// requires php, curl, gd, allow_url_fopen

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// configuration

  // see http://w1.weather.gov/xml/current_obs/
  // to find the URL for your local weather

  $xml_url      = 'http://w1.weather.gov/xml/current_obs/KDEN.xml';
  $location     = 'Denver, CO';
  $local_icons  = '';                   // get icons from www.weather.gov
  $temp_in      = 'C';                  // C or F

  $cache_image  = '/tmp/weather.gif';   // cache image on server
  $cache_time   = 900;                  // update every 15 minutes

  $background   = '#000000';
  $text_color   = '#FFFFFF';

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// showtime

  header('Content-type: image/gif');

  if ($cache_image) {
    if ($image = check_image($cache_image)) {
      readfile($image);
    }
  } else {
    rebuild_image(null);
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// check cached image

  function check_image ($cache_image) {
    global $cache_time;
    $rebuild_image = false;

    if (is_file($cache_image)) {
      if ($_GET['rebuild']) {
        $rebuild_image = true;
      } else if ((time() - filemtime($cache_image)) > $cache_time) {
        $rebuild_image = true;
      }
    } else {
      $rebuild_image = true;
    }
    if ($rebuild_image) {
      return rebuild_image($cache_image);
    } else {
      return $cache_image;
    }
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// rebuild image

  function rebuild_image ($file) {
    global $xml_url, $location;
    global $background, $text_color;

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // get data

    if ($data = get_xml_data($xml_url)) {
      $data = hack_data($data);
    } else {
      return false;
    }
    $n = count($data['keys']);

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // image parameters

    $width      = 200;
    $height     = 100;                  // will be computed

    $loc_f      = 4;
    $line_f     = 2;
    $margin     = 3;

    $loc_h = imagefontheight($loc_f) + $margin;
    $line_h = imagefontheight($line_f) + $margin;
    $block_h = $n * $line_h;

    if ($icon = get_icon($data)) {
      $icon_h = imagesy($icon) + $margin;

      if ($icon_h > $block_h) {
        $height = $margin + $loc_h + $icon_h + $line_h;
      } else {
        $height = $margin + $loc_h + $block_h + $line_h;
      }
    } else {
      $height = $margin + $loc_h + $block_h + $line_h;
    }

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // create image

    $image = imagecreatetruecolor($width,$height);
    $background = alloc_color($image,$background,255,255,255);
    imagefill($image,0,0,$background);

    $x = (2 * $margin); $y = $margin;
    $text_color = alloc_color($image,$text_color,0,0,0);

    if ($center_location) {
      $loc_w = strlen($location) * imagefontwidth($loc_f);
      $c = intval(($width - $loc_w) / 2); if ($c > $x) $x = $c;
    }
    imagestring($image,$loc_f,$x,$y,$location,$text_color);
    $x = (2 * $margin); $y += $loc_h;

    if ($icon) {
      imagecopy($image,$icon,$x,$y,0,0,imagesx($icon),imagesy($icon));
      $x += imagesx($icon) + (2 * $margin); $clear_y = $y + $icon_h;
    }
    foreach ($data['keys'] as $key) {
      imagestring($image,$line_f,$x,$y,$data[$key],$text_color);
      $y += $line_h;
    }
    $x = (2 * $margin); if ($clear_y > $y) $y = $clear_y;
    imagestring($image,$line_f,$x,$y,$data['updated'],$text_color);

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    if (imagegif($image,$file)) {
      return $file;
    } else {
      imagegif($image); return;
    }
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// get xml data

  function get_xml_data ($url) {
    $get = curl_init($url);
    curl_setopt($get,CURLOPT_USERAGENT,'Netscape/0.92b'); 
    curl_setopt($get,CURLOPT_FAILONERROR,true);
    curl_setopt($get,CURLOPT_RETURNTRANSFER,true);

    $xml = curl_exec($get);
    $info = curl_getinfo($get);

    if (curl_errno($get) || ! $xml || $info['http_code'] != 200) {
      curl_close($get); return false;
    } else {
      curl_close($get); return parse_xml($xml);
    }
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// parse xml
// an alarmingly simple parser

  function parse_xml (&$tokens,$parent = '') {
    if (! is_array($tokens)) {
      $flags = PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE;
      $tokens = preg_split('/(<[^>]+>)\s*/',$tokens,-1,$flags);
    }
    if ($parent) {
      $end_tag = sprintf('!</%s\\b!',$parent);
    }
    while ($tokens) {
      $token = array_shift($tokens);

      if (preg_match('/<\?xml.*\?>/',$token)) {
        continue;
      } else if ($end_tag && preg_match($end_tag,$token)) {
        return $data;
      } else if (preg_match('/<(\w+)/',$token,$match)) {
        $data[$match[1]] = parse_xml($tokens,$match[1]);
      } else {
        $data = $token;
      }
    }
    return $data;
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// hack data

  function hack_data ($data) {
    global $temp_in;
    $data = $data['current_observation'];

    if ($data['weather'] != 'NA') {
      $keys = array('weather');
    } else {
      $data['none'] = 'No weather information';
      $data['keys'] = array('none'); return $data;
    }
    if ($temp = hack_temp($data)) {
      $data['temp'] = $temp;
      $keys[] = 'temp';
    }
    if (($pct = $data['relative_humidity']) != 'NA') {
      $data['humidity'] = sprintf('%d%% humidity',$pct);
      $keys[] = 'humidity';
    }
    if ($wind = hack_wind($data)) {
      $data['wind'] = $wind;
      $keys[] = 'wind';
    }
    if ($data['pressure_in'] != 'NA') {
      $u = ($temp_in == 'C') ? 'mb' : 'in';
      $fmt = 'Barometer %s %s';

      $data['barometer'] = sprintf($fmt,$data['pressure_'.$u],$u);
      $keys[] = 'barometer';
    }
    $data['keys'] = $keys;

    if ($time = $data['observation_time']) {
      if (preg_match('/on (\w+ \d+, \d+:\d+ \w+)/',$time,$match)) {
        $data['updated'] = 'Updated: '.$match[1];
      }
    }
    return $data;
  }

  function lc ($string) { return strtolower($string); }
  function uc ($string) { return strtoupper($string); }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// hack temperature

  function hack_temp ($data) {
    global $temp_in;

    $temp_fmt = '%d'.$temp_in;
    $ext_fmt = "$temp_fmt ($temp_fmt %s)";
    $t = lc($temp_in);

    if (($deg = $data['temp_'.$t]) != 'NA') {
      if (($ext = $data['heat_index_'.$t]) != 'NA') {
        $temp = sprintf($ext_fmt,$deg,$ext,'heat index');
      } else if (($ext = $data['windchill_'.$t]) != 'NA') {
        $temp = sprintf($ext_fmt,$deg,$ext,'windchill');
      } else {
        $temp = sprintf($temp_fmt,$deg);
      }
    }
    return $temp;
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// hack wind

  function hack_wind ($data) {
    global $temp_in;

    $speed_fmt = '%d %s';
    $wind_fmt = 'Wind %s at %s';

    if ($wind_str = $data['wind_string']) {
      if ($wind_str == 'Calm') {
        return 'Wind calm';
      }
    }
    if ($wind_dir = $data['wind_dir']) {
      if ($wind_dir == 'None') {
        return 'No wind';
      } else if ($wind_dir == 'Variable') {
        $wind_dir = 'Vary';
      } else if (preg_match('/^([NS])\w+([ew])\w+/',$wind_dir,$match)) {
        $wind_dir = uc($match[1].$match[2]);
      } else if (preg_match('/^([NSEW])\w+/',$wind_dir,$match)) {
        $wind_dir = uc($match[1]);
      }
    }
    if (($speed = $data['wind_mph']) != 'NA') {
      if ($temp_in == 'C') {
        $speed = sprintf($speed_fmt,(($speed * 1.609) + 0.5),'kph');
      } else {
        $speed = sprintf($speed_fmt,($speed + 0.5),'mph');
      }
    }
    if ($wind_dir && $speed) {
      $wind = sprintf($wind_fmt,$wind_dir,$speed);
    }
    return $wind;
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// get icon

  function get_icon ($data) {
    global $local_icons;

    if ($local_icons) {
      $icon_path = $local_icons.'/'.$data['icon_url_name'];
    } else {
      $icon_path = $data['icon_url_base'].$data['icon_url_name'];
      ini_set('user_agent','Netscape/0.92b');
    }
    if (preg_match('/\.gif/',$data['icon_url_name'])) {
      $icon = imagecreatefromgif($icon_path);
    } else if (preg_match('/\.(jpg|jpeg)/',$data['icon_url_name'])) {
      $icon = imagecreatefromjpeg($icon_path);
    } else if (preg_match('/\.png/',$data['icon_url_name'])) {
      fclose(STDERR);   // dump interlace error in libpng
      $icon = imagecreatefrompng($icon_path);
    }
    return $icon;
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// allocate color

  function alloc_color ($image,$color,$r,$g,$b) {
    $dec_re = '/(\d+),\s*(\d+),\s*(\d+)/';
    $hex_re = '/#([0-9a-z]{2})([0-9a-z]{2})([0-9a-z]{2})/i';

    if (preg_match($dec_re,$color,$m)) {
      $r = $m[1]; $g = $m[2]; $b = $m[3];
    } else if (preg_match($hex_re,$color,$m)) {
      $r = hexdec($m[1]); $g = hexdec($m[2]); $b = hexdec($m[3]);
    }
    return imagecolorallocate($image,$r,$g,$b);
  }

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
?>