/*
   Behaviour v1.0 by Ben Nolan, June 2005. Based largely on the work
   of Simon Willison (see comments by Simon below).
   Binds JS events to xhtml elements by means of css selectors
*/

var Behaviour = {
	list : new Array,

	register : function(sheet){
		Behaviour.list.push(sheet);
	},

	start : function(){
		//alert("start was fired");
		Behaviour.addLoadEvent(function(){
			Behaviour.apply();
		});
	},

	apply : function(){
		if (Behaviour.list.length == 0) {
			//alert("apply was fired but zero rules found");
		} else {
			//alert("apply was fired with " + Behaviour.list.length + " rules found");
		}
		for (h=0;sheet=Behaviour.list[h];h++){
			for (selector in sheet){
				list = document.getElementsBySelector(selector);

				if (!list){
					continue;
				}

				for (i=0;element=list[i];i++){
					sheet[selector](element);
				}
			}
		}
	},

	addLoadEvent : function(func){
		var oldonload = window.onload;

		if (typeof window.onload != 'function') {
			window.onload = func;
		} else {
			window.onload = function() {
				oldonload();
				func();
			}
		}
	}
}

Behaviour.start();
//alert("behaviour start");

function getAllChildren(e) {
  // Returns all children of element. Workaround required for IE5/Windows. Ugh.
  return e.all ? e.all : e.getElementsByTagName('*');
}

document.getElementsBySelector = function(selector) {	
  // Attempt to fail gracefully in lesser browsers
  if (!document.getElementsByTagName) {
    //alert("sorry no JS binding in your browser!");
    return new Array();
  }
  // Split selector in to tokens
  var tokens = selector.split(' ');
  var currentContext = new Array(document);
  for (var i = 0; i < tokens.length; i++) {
    token = tokens[i].replace(/^\s+/,'').replace(/\s+$/,'');;
    if (token.indexOf('#') > -1) {
      // Token is an ID selector
      //alert("there were an ID selector");
      var bits = token.split('#');
      var tagName = bits[0];
      var id = bits[1];
      var element = document.getElementById(id);
      if (tagName && element.nodeName.toLowerCase() != tagName) {
        // tag with that ID not found, return false
        return new Array();
      }
      // Set currentContext to contain just this element
      currentContext = new Array(element);
      continue; // Skip to next token
    }
    if (token.indexOf('.') > -1) {
      // Token contains a class selector
      var bits = token.split('.');
      var tagName = bits[0];
      var className = bits[1];
      if (!tagName) {
        tagName = '*';
      }
      // Get elements matching tag, filter them for class selector
      var found = new Array;
      var foundCount = 0;
      for (var h = 0; h < currentContext.length; h++) {
        var elements;
        if (tagName == '*') {
            elements = getAllChildren(currentContext[h]);
        } else {
            elements = currentContext[h].getElementsByTagName(tagName);
        }        
        for (var j = 0; j < elements.length; j++) {
          found[foundCount++] = elements[j];
        }
      }
      currentContext = new Array;
      var currentContextIndex = 0;
      for (var k = 0; k < found.length; k++) {
        if (found[k].className && found[k].className.match(new RegExp('\\b'+className+'\\b'))) {
          currentContext[currentContextIndex++] = found[k];
        }
      }
      continue; // Skip to next token
    }
    // Code to deal with attribute selectors
    if (token.match(/^(\w*)\[(\w+)([=~\|\^\$\*]?)=?"?([^\]"]*)"?\]$/)) {
      var tagName = RegExp.$1;
      var attrName = RegExp.$2;
      var attrOperator = RegExp.$3;
      var attrValue = RegExp.$4;
      if (!tagName) {
        tagName = '*';
      }
      // Grab all of the tagName elements within current context
      var found = new Array;
      var foundCount = 0;
      for (var h = 0; h < currentContext.length; h++) {
        var elements;
        if (tagName == '*') {
            elements = getAllChildren(currentContext[h]);
        } else {
            elements = currentContext[h].getElementsByTagName(tagName);
        }
        for (var j = 0; j < elements.length; j++) {
          found[foundCount++] = elements[j];
        }
      }
      currentContext = new Array;
      var currentContextIndex = 0;
      var checkFunction; // This function will be used to filter the elements
      switch (attrOperator) {
        case '=': // Equality
          checkFunction = function(e) { return (e.getAttribute(attrName) == attrValue); };
          break;
        case '~': // Match one of space seperated words
          checkFunction = function(e) { return (e.getAttribute(attrName).match(new RegExp('\\b'+attrValue+'\\b'))); };
          break;
        case '|': // Match start with value followed by optional hyphen
          checkFunction = function(e) { return (e.getAttribute(attrName).match(new RegExp('^'+attrValue+'-?'))); };
          break;
        case '^': // Match starts with value        	
          checkFunction = function(e) {	          	
          	if ( e.getAttribute(attrName) == null ) {           		
          		//console.log("null: " + attrName);
          		return false;
          	}
          	return ( e.getAttribute(attrName).indexOf(attrValue) == 0 ); 
          };
          break;
        case '$': // Match ends with value - fails with "Warning" in Opera 7
          checkFunction = function(e) { return (e.getAttribute(attrName).lastIndexOf(attrValue) == e.getAttribute(attrName).length - attrValue.length); };
          break;
        case '*': // Match ends with value
          checkFunction = function(e) { return (e.getAttribute(attrName).indexOf(attrValue) > -1); };
          break;
        default :
          // Just test for existence of attribute
          checkFunction = function(e) { return e.getAttribute(attrName); };
      }
      currentContext = new Array;
      var currentContextIndex = 0;      
      for (var k = 0; k < found.length; k++) {
        if (checkFunction(found[k])) {
          currentContext[currentContextIndex++] = found[k];
        }
      }
      // alert('Attribute Selector: '+tagName+' '+attrName+' '+attrOperator+' '+attrValue);
      continue; // Skip to next token
    }

    if (!currentContext[0]){
    	return;
    }

    // If we get here, token is JUST an element (not a class or ID selector)
    tagName = token;
    var found = new Array;
    var foundCount = 0;
    for (var h = 0; h < currentContext.length; h++) {
      var elements = currentContext[h].getElementsByTagName(tagName);
      for (var j = 0; j < elements.length; j++) {
        found[foundCount++] = elements[j];
      }
    }
    currentContext = found;
  }
  return currentContext;
}