//
// pbTitle         - Titel van het photobook
// pbPhotos        - Array met afbeeldingen van het photobook
// pbThumbWidth    - Breedte in pixels van een thumbnail
// pbThumbHeight   - Hoogte in pixels van een thumbnail
// pbPhotoWidth    - Breedte in pixels van een foto
// pbPhotoHeight   - Hoogte in pixels van een foto
// pbCurrentItem   - Actieve foto
//
var pbTitle = null;
var pbPhotos = new Array();
var pbThumbWidth = 80;
var pbThumbHeight = 60;
var pbPhotoWidth = 488;
var pbPhotoHeight = 366;
var pbCurrentItem = 0;

//
// Inladen navigatie afbeeldingen
//
var pbNavPrev = new Image( 35, 60 );
var pbNavPrevDisabled = new Image( 35, 60 );
var pbNavNext = new Image( 35, 60 );
var pbNavNextHover = new Image( 35, 60 );
var pbNavNextDisabled = new Image( 35, 60 );
var pbThumbFirstPhoto = new Image( 80, 60 );
var pbThumbLastPhoto = new Image( 80, 60 );

pbNavPrev.src = 'photobook/images/pbNavPrev.png';
pbNavPrevDisabled.src = 'photobook/images/pbNavPrevDisabled.png';
pbNavNext.src = 'photobook/images/pbNavNext.png';
pbNavNextHover.src = 'photobook/images/pbNavNextHover.png';
pbNavNextDisabled.src = 'photobook/images/pbNavNextDisabled.png';
pbThumbFirstPhoto.src = 'photobook/images/pbThumbFirstPhoto.png';
pbThumbLastPhoto.src = 'photobook/images/pbThumbLastPhoto.png';

//
// Maak XMLHttpRequest compatible voor alle browsers (IE, Firefox, Opera)
//
if( typeof XMLHttpRequest == "undefined" )
{
	XMLHttpRequest = function()
	{
		try { return new ActiveXObject("Msxml2.XMLHTTP.6.0"); } catch(e) {};
		try { return new ActiveXObject("Msxml2.XMLHTTP.3.0"); } catch(e) {};
		try { return new ActiveXObject("Msxml2.XMLHTTP"); }     catch(e) {};
		try { return new ActiveXObject("Microsoft.XMLHTTP"); }  catch(e) {};
	
		throw new Error("This browser does not support XMLHttpRequest or XMLHTTP.");
	};
}

//
// Functie	: pbInit( pbDirectory )
// Parameter(s)	: pbDirectory - string met de directory waar het 'album.txt' bestand staat
//
function pbInit( pbDirectory )
{

	// Corrigeer een eventuele missende backslash in de directory-naam
	if( pbDirectory.substr( pbDirectory.length - 1, 1 ) != "/" )
	{
		pbDirectory = pbDirectory + "/";
	}
	
	// Lees het 'album.txt' bestand in de betreffende directory
	var req = new XMLHttpRequest();
	req.open("GET", pbDirectory + "album.txt", false);
	req.send(null);
	
	// Verwerk de gegevens uit 'album.txt'
	var tmp = req.responseText.split("\n");
	
	pbTitle = tmp[0];
	for (i=1; i<tmp.length; i++)
	{
		if (tmp[i] != "")
		{
			pbPhotos[i-1] = new Array();
			pbPhotos[i-1]['thumb'] = new Image( pbThumbWidth, pbThumbHeight );
			pbPhotos[i-1]['thumb'].src = pbDirectory + "thumb/" + tmp[i].split( "|" )[0];
			pbPhotos[i-1]['photo'] = new Image( pbPhotoWidth, pbPhotoHeight );
			pbPhotos[i-1]['photo'].src = pbDirectory + tmp[i].split( "|" )[0];
			pbPhotos[i-1]['comment'] = tmp[i].split( "|" )[1];
			
			if (pbPhotos[i-1]['comment'] == '')
			{
				pbPhotos[i-1]['comment'] = '&nbsp;';
			}
		}
	}
	document.getElementById('pbTitle').innerHTML = pbTitle;
	pbDraw();
}






//
// pbDraw();
//
function pbDraw()
{
	for( i=0; i<=2; i++ )
	{
		if( ( pbCurrentItem == 0 ) && ( i == 0 ) )
		{
			document.getElementById( 'pbThumbPhoto' + ( i + 1 ) ).src = pbThumbFirstPhoto.src;
		}
		else if ( ( pbCurrentItem == pbPhotos.length - 1 ) && i == 2 )
		{
			document.getElementById( 'pbThumbPhoto' + ( i + 1 ) ).src = pbThumbLastPhoto.src;
		}
		else
		{
			document.getElementById( 'pbThumbPhoto' + ( i + 1 ) ).src = pbPhotos[pbCurrentItem + i - 1]['thumb'].src;
		}
		
		document.getElementById( 'pbPhotoImage' ).src = pbPhotos[pbCurrentItem]['photo'].src;
		document.getElementById( 'pbComment' ).innerHTML = pbPhotos[pbCurrentItem]['comment'];
	}

	if( pbCurrentItem == 0 )
	{
		document.getElementById( 'pbNavPrevImage' ).src = pbNavPrevDisabled.src;
	}
	else
	{
		document.getElementById( 'pbNavPrevImage' ).src = pbNavPrev.src;
	}


	if (pbCurrentItem == pbPhotos.length - 1)
	{
		document.getElementById( 'pbNavNextImage' ).src = pbNavNextDisabled.src;
	}
	else
	{
		document.getElementById( 'pbNavNextImage' ).src = pbNavNext.src;
	}
	
	document.getElementById('pbTitle').innerHTML = pbTitle + ' (' + (pbCurrentItem + 1) + '/' + pbPhotos.length + ')';
}


//
// pbNavScroll()
//
function pbNavScroll(direction)
{
	if( ( direction == 'prev') && ( pbCurrentItem > 0 ) )
	{
		pbCurrentItem--;
		pbDraw();
	}

	else if( ( direction == 'next' ) && ( pbCurrentItem < pbPhotos.length - 1 ) )
	{
		pbCurrentItem++;
		pbDraw();
	}
}