var block_height = 391;


function init_homepage() {
	if (init_block) {
		init_block('homepage_intro');
		init_block('homepage_buffetten');
		init_block('homepage_aanbieding');
		init_block('homepage_referenties');
	}
}

function init_block(block_id) {

	var block = document.getElementById(block_id);
	
	var lis = block.getElementsByTagName('li');

	if (lis) {
		// Is er meer dan 1 onderdeel? Voeg dan de vorige en volgende pijltjes toe.
		if (lis.length > 1) {
		
			var prev_button = document.createElement('div');
			var next_button = document.createElement('div');
			
			if (prev_button) {
				prev_button.style.backgroundImage = 'url(images/' + block_id + '_prev.gif)';
				prev_button.id = block_id + '_prev';
				prev_button.className = 'prev_button';
				prev_button.onclick = move_content;
				prev_button.onmouseover = homepage_button_mouseover;
				prev_button.onmouseout = homepage_button_mouseout;
			}
			
			if (next_button) {
				next_button.style.backgroundImage = 'url(images/' + block_id + '_next.gif)';
				next_button.id = block_id + '_next';
				next_button.className = 'next_button';
				next_button.onclick = move_content;
				next_button.onmouseover = homepage_button_mouseover;
				next_button.onmouseout = homepage_button_mouseout;
			}
			
			block.appendChild(prev_button);
			block.appendChild(next_button);
		}
		
		if (lis.length > 0) {
			for (var i = 0; i < lis.length; i++) {
			
				var spans = lis[i].getElementsByTagName('span');
				
				if (spans && spans.length > 0) {
					
					var ahrefs = spans[0].getElementsByTagName('a');
					
					if (ahrefs && ahrefs.length > 0) {
						spans[0].href = ahrefs[0].href;
						spans[0].onclick = function() {
							document.location = this.href;
						}
						spans[0].innerHTML = ahrefs[0].innerHTML;
					}
				}
			}
		}
	}
}

function move_content() {
	
	// Bepaal het contentblok aan de hand van de id van het aangeklikte knopje
	var matches = this.id.match(/^([^_]*_[^_]*)_([^_]*)$/);
	
	if (matches) {
		
		var content_block_id = matches[1];
		var direction = matches[2];
		
		// alert("block: " + content_block_id + ", direction: " + direction);
		
	} else {
		return false;
	}
	
	var content_block = document.getElementById(content_block_id);
	
	if (!content_block) {
		return false;
	}
	
	
	// Bepaal het aantal items in het contentblock
	var lis = content_block.getElementsByTagName('li');
	
	if (!lis || lis.length <= 1) {
		return false;
	}
	
	var totale_hoogte = lis.length * block_height;
	
	// Bepaal de huidige positie van de ul
	var ul = content_block.getElementsByTagName('ul');
	
	if (ul && ul.length > 0) {
		ul = ul[0];
		var top = ul.offsetTop;
	} else {
		return false;
	}
	
	if (direction == 'next') {
		if (top > 0 - (totale_hoogte - block_height)) {
			top = top - block_height;
		} else {
			top = 0;
		}
	} else { // direction == prev
		if (top < 0) {
			top = top + block_height;
		} else {
			top = 0 - (totale_hoogte - block_height);
		}
	}
	
	ul.style.top = top + 'px';
	
	// Bepaal de breedte van de content door het aantal blokken te tellen.
	return true;
}

function homepage_button_mouseover() {
	var backgroundImage = this.style.backgroundImage;
	
	var parts = backgroundImage.match(/\(images\/(.*)(_hover){0,1}\.gif\)/);
	
	if (parts) {
		this.style.backgroundImage = 'url(images/' + parts[1] + '_hover.gif)';
	}
	
}

function homepage_button_mouseout() {
	var backgroundImage = this.style.backgroundImage;
	
	var parts = backgroundImage.match(/\(images\/(.*?)(_hover){0,1}\.gif\)/);
	
	if (parts) {
		this.style.backgroundImage = 'url(images/' + parts[1] + '.gif)';
	}
	
}