/*
 * Gets temperature data from Yahoo RSS feed and displays it numerically
 * on the canvas.
 * 
 * Copyright (C) 2012-2013 Mithat Konar
 */

// Constants:
// change the URL to get the desired location and units
// (see http://developer.yahoo.com/weather/).
final String URL = "http://weather.yahooapis.com/forecastrss?w=12781882&u=f";
 
// path in XML data to current conditions:
final String ELEMENT_CONDITION="channel/item/yweather:condition";
 
// attribute name in element above for current temperature:
final String ATTRIBUTE_CONDITION_TEMPERATURE = "temp";
 
// path in XML data to element that holds units of measurement:
final String ELEMENT_UNITS = "channel/yweather:units";
 
// attribute name in element above that holds units for temperature:
final String ATTRIBUTE_UNIT_TEMPERATURE = "temperature";
 
// misc.
final int CANVAS_BORDER=10;

// Functions:
void setup() {
  size(250, 140);
  smooth(); 

  try {
    XML weather = loadXML(URL);  // instantiate an XML object from URL
    XML condition = weather.getChild(ELEMENT_CONDITION);  // pull current cond.
    XML units = weather.getChild(ELEMENT_UNITS);  // pull units data

    background(#296783);

    PFont font;  // we'll use this to hold font data
    font = loadFont("Monospaced.bold-48.vlw"); 
    textFont(font, 48);
    textAlign(CENTER, CENTER);
    fill(#ffffff);
    text(condition.getInt(ATTRIBUTE_CONDITION_TEMPERATURE) + "\u00b0" + units.getString(ATTRIBUTE_UNIT_TEMPERATURE), width/2, height/2);
  }
  catch (Exception e) {
    println("Problem loading " + URL);
    println(e);

    // Turn the canvas red with a big 'X' in it to indicate error.
    background(#ff0000);
    strokeWeight(5);
    line(CANVAS_BORDER, CANVAS_BORDER, width-CANVAS_BORDER, height-CANVAS_BORDER);
    line(CANVAS_BORDER, height-CANVAS_BORDER, width-CANVAS_BORDER, CANVAS_BORDER);
  }
  
  println("Exiting app.");
}