// -*- JavaScript -*-

// Adapted from <http://www.bazon.net/mishoo/toc.epl>

function H_getText(el) {
  var text = "";
  for (var i = el.firstChild; i != null; i = i.nextSibling) {
    if (i.nodeType == 3 /* Node.TEXT_NODE, IE doesn't speak constants */)
      text += i.data;
    else if (i.firstChild != null)
      text += H_getText(i);
  }
  return text;
}

function TOC_EL(el, text, level) {
  this.element = el;
  this.text = text;
  this.level = level;
}

function getHeadlines(el) {
  var l = new Array;
  var rx = /[hH]([1-6])/;
  // internal recursive function that scans the DOM tree
  var rec = function (el) {
    for (var i = el.firstChild; i != null; i = i.nextSibling) {
      if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
        if (rx.exec(i.tagName))
          l[l.length] = new TOC_EL(i, H_getText(i), parseInt(RegExp.$1));
        rec(i);
      }
    }
  }
  rec(el);
  return l;
}

function generate_TOC(parent_id) {
    var parent = document.getElementById(parent_id);
    var body = document.getElementsByTagName("body")[0];
    body.id = "Top";
    var hs = getHeadlines(body);
    // for (var i = 0; i < hs.length; ++i) {
    //   var hi = hs[i];

    //   var d = document.createElement("div");
    //   if (hi.element.id == "")
    //      hi.element.id = "gen" + i;
    //   var a = document.createElement("a");
    //   a.href = "#" + hi.element.id;
    //   a.appendChild(document.createTextNode(hi.text));
    //   d.appendChild(a);
    //   d.className = "level" + hi.level;
    //   parent.appendChild(d);
    // }

      
    // The code below assumes the first level is always higher than
    // or equal to all the levels that apper later. There is no
    // guarantee, however, that levels do not hop. For example,
    // level 3 could appear right after level 1, skipping level 2.

    var make_list_elm = function ( hdr ) {
	var a = document.createElement("a");
	a.href = "#" + hdr.element.id;
	a.appendChild( document.createTextNode( hdr.text ) );
	return a;
    }
    
    var listtops = new Array ;
    listtops[ 0 ] =  parent ;
    
    var current_level = 0 ;
    
    var make_list = function ( elm ) {
      if ( elm.level <= current_level ) {
	  current_level = elm.level ;
	  var li = document.createElement( "li" ); // List Item
	  li.id = "Ind" + elm.element.id ;
	  li.appendChild( make_list_elm( elm ) );
	  listtops[ current_level ].appendChild( li );
      }	else { // elm.level > current_level 
	  var lt = document.createElement( "ul" ); // List Top
	  listtops[ current_level ].appendChild( lt );
	  listtops[ ++current_level ] = lt ;
	  lt.className = "Level" + current_level ;
	  make_list ( elm ); 
      }
    }

    for ( var i = 0; i < hs.length; ++i ) {
	var hi = hs[i];

	if (hi.element.id == "")  hi.element.id = "Cnt" + i;
	
	make_list ( hi );
    }

    var createList = function ( ) { /* takes variable number of arguments */
	var ul = document.createElement( "ul" );

	ul.className = "sectnav";

	for ( var i = 0; i < arguments.length; i++ ) {
	    var li = document.createElement( "li" );

	    li.innerHTML=arguments[i];
	    ul.appendChild ( li );
	}

	return ul; 
    }	

    
    
    for ( var i = 0; i < hs.length; ++i ) {
	var node = hs[i].element;
	

	var l = createList ( 
	    '[<a href="javascript:window.history.back();">back</a>]',
            '[<a href="#Top">top</a>]', 
	    '[<a href="#Ind' + node.id + '">index</a>]'
	);


	/* marginBottom = node.style.marginBottom; */
	marginBottom = getStyle(node, "margin-bottom"); 
	node.style.marginBottom = "0px" ;
	l.style.marginBottom = marginBottom;
	node.parentNode.insertBefore(l, node.nextSibling);
    }

}


// from <http://dhtmlkitchen.com/learn/js/setstyle/index4.jsp>

function getStyle(el, style) {
   if(!document.getElementById) return;
   
     var value = el.style[toCamelCase(style)];
   
    if(!value)
        if(document.defaultView)
            value = document.defaultView.
                 getComputedStyle(el, "").getPropertyValue(style);
       
        else if(el.currentStyle)
            value = el.currentStyle[toCamelCase(style)];
     
     return value;
}

/** toCamelCase(input)
 * Converts string input to a camel cased version of itself.
 * For example:
 * toCamelCase("z-index"); // returns zIndex
 * toCamelCase("border-bottom-style"); // returns borderBottomStyle.
 */
function toCamelCase(s) {
	for(var exp = toCamelCase.exp; 
		exp.test(s); s = s.replace(exp, RegExp.$1.toUpperCase()) );
	return s;
}
toCamelCase.exp = /-([a-z])/;