/**
 * FullWIdthNav 1.0 (Requires the dimensions plug-in)
 *
 * Takes any navigation built from a "ul li a" setup and increases
 * each a's padding left/right so that the entire row of lis/as take
 * up the full space of their parent.
 *
 * Usage: jQuery('#navigation, ul.tabs').fullWidthNav();
 *
 * @class fullWidthNav
 *
 * Copyright (c) 2008 Andreas Lagerkvist (andreaslagerkvist.com)
 * Released under a GNU General Public License v3 (http://creativecommons.org/licenses/by/3.0/)
 */
jQuery.fn.fullWidthNav = function() {
	// Always return each...
	return this.each(function() {
		var ul = jQuery(this), 
			navWidth = ul.innerWidth(), 
			tabWidth = 0, 
			numTabs = 0, 
			diff = 0, 
			diffLeft = 0, 
			diffRight = 0, 
			lastDiff = 0, 
			lastDiffLeft = 0, 
			lastDiffRight = 0, 
			totalDiff = 0, 
			tabPaddingLeft = parseInt(jQuery('a', ul).css('paddingLeft'), 10), 
			tabPaddingRight = parseInt(jQuery('a', ul).css('paddingRight'), 10), 
			tabMarginRight = parseInt(jQuery('li', ul).css('marginRight'), 10);

		// Get the width of all the tabs and the number of tabs
		jQuery('li', ul).each(function() {
			tabWidth += jQuery(this).outerWidth() + tabMarginRight;
			numTabs++;
		});

		// Make sure last li has no margin-right and subtract the last li's margin-right from the total width of the tabs
		tabWidth -= jQuery('li:last-child', ul).css('marginRight');
		jQuery('li:last-child', ul).css({marginRight: 0});

		// Calculate the difference between the tabWidth and the navWidth
		// and how much each tab needs to increase in width
		// Take care of fractionals and add them to the last li
		totalDiff = navWidth - tabWidth;

		// IF the tabWidth is actually larger than the navWidth the diff will be negative and
		// we need to use ceil rather than floor (floor(-14.33) == 15, ceil(-14.33) == 14 and that's what we want in this case...)
		if(totalDiff > 0) {
			diff = Math.floor(totalDiff / numTabs);
		}
		else {
			diff = Math.ceil(totalDiff / numTabs);
		}

		lastDiff = diff + totalDiff % numTabs;

		// We may need to have different padding left and right values depending
		// on fractional pixels again... bloody pain this!
		if(diff > 0) {
			diffLeft = diffRight = Math.floor(diff / 2);
		}
		else {
			diffLeft = diffRight = Math.ceil(diff / 2);
		}

		diffRight += diff % 2;

		if(lastDiff > 0) {
			lastDiffLeft = lastDiffRight = Math.floor(lastDiff / 2);
		}
		else {
			lastDiffLeft = lastDiffRight = Math.ceil(lastDiff / 2);
		}

		lastDiffRight += lastDiff % 2;

	//	console.log('Navigation\'s width is ' +navWidth +'px, the ' +numTabs +' tabs in this nav takes up a total of ' +tabWidth +'px width (' +tabMarginRight +'px margin-right included) need to increase total tab width with ' +totalDiff +'px (' +diff +'px per tab and ' +lastDiff +'px on the last tab)');

		// Now increae every tab's link's left/right padding to make them take up all available space
		jQuery('li', ul).each(function(i) {
			var li = jQuery(this), 
				pl = diffLeft + tabPaddingLeft, 
				pr = diffRight + tabPaddingRight;

			// If last tab...
			if(i === (numTabs-1)) {
				pl = lastDiffLeft + tabPaddingLeft;
				pr = lastDiffRight + tabPaddingRight;
			}

			// Negative padding is not allowed...
			if(pl < 0) {
				pl = 0;
			}
			if(pr < 0) {
				pr = 0;
			}

			jQuery('a', li).css({paddingLeft: pl +'px', paddingRight: pr +'px'});
		});
	});
};