// configuration

var sandwichTop, sandwichBottom, sandwichTopDiv, sandwichBottomDiv, sandwichTopWidth, sandwichBottomWidth, sandwichTopRatio, sandwichBottomRatio, topDimW, topDimH, botDimW, botDimH; // must be global
jQuery.fn.splitBg = function(top,bottom,color,topDims,botDims) {
	var topImage = top || 0;
	var bottomImage = bottom || 0;
	var theBgColor = color || '#333';
	topDimW = topDims[0] || 1;
	topDimH = topDims[1] || 1;
	botDimW = botDims[0] || 1;
	botDimH = botDims[1] || 1;
	jQuery('html').css('background-color',theBgColor);
	jQuery('body').css({'background': 'none'});
	if (topImage) jQuery('body').prepend('<div id="bgSandwichTop" style="position: absolute; top: 0; z-index: -1; overflow: hidden;"><img style="position: absolute; z-index: -1;" src="' + topImage + '" alt="" /></div>');
	if (bottomImage) jQuery('#pageContentContainer').append('<div id="bgSandwichBottom" style="position: absolute; bottom: 0; z-index: -1; overflow: hidden;"><img src="' + bottomImage + '" alt="" /></div>');
	
	// shortcut vars and initial dimensions
	sandwichTopDiv = jQuery('#bgSandwichTop');
	sandwichBottomDiv = jQuery('#bgSandwichBottom');
	sandwichTop = jQuery('#bgSandwichTop img');
	sandwichBottom = jQuery('#bgSandwichBottom img');
	sandwichTopWidth = sandwichTop.width();
	sandwichTopRatio = topDimW / topDimH;
	sandwichBottomWidth = sandwichBottom.width();
	sandwichBottomRatio = botDimW / botDimH;
	
	// set size of containers
	var pccH = jQuery('#pageContentContainer').height();
	var bH = jQuery('body').height();
	if (pccH < bH) jQuery('#pageContentContainer').height(bH);
	
	// set initial size/position
	jQuery().moveSandwich();
	
	// create resize event
	jQuery(window).resize(function() {
		jQuery().moveSandwich();
	});
}

jQuery.fn.moveSandwich = function() { // positions images centered on page
	// get current centers
	var pageCenter = jQuery(window).width() / 2;
	var sandwichTopCenter = sandwichTopWidth / 2;
	var sandwichBottomCenter = sandwichBottomWidth / 2;
	
	// check to see if window is bigger than img; if so, scale images
	if (pageCenter > sandwichTopCenter) {
		var winWidth = jQuery(window).width();
		sandwichTopDiv.width(winWidth).height(winWidth/sandwichTopRatio);
		sandwichTop.width(winWidth).height(winWidth/sandwichTopRatio);
		sandwichTopCenter = pageCenter;
	} else {
		sandwichTopDiv.width(sandwichTopWidth).height(sandwichTopWidth / sandwichTopRatio);
		sandwichTop.width(sandwichTopWidth).height(sandwichTopWidth / sandwichTopRatio);
	}
	if (pageCenter > sandwichBottomCenter) {
		var winWidth = jQuery(window).width();
		sandwichBottom.width(winWidth).height(winWidth/sandwichBottomRatio);
		sandwichBottomCenter = pageCenter;
	} else {
		sandwichBottom.width(sandwichBottomWidth).height(sandwichBottomWidth / sandwichBottomRatio);
	}
	
	// center images
	sandwichTop.css('left', (0 - (sandwichTopCenter - pageCenter)) + 'px');
	sandwichBottom.css('left', (0 - (sandwichBottomCenter - pageCenter)) + 'px');
	
	// resize containing divs
	sandwichTopDiv.width(jQuery(window).width());
	sandwichBottomDiv.width(jQuery(window).width());
}