var page = (function() {

	var $container = $( '#container' ),
		$bookblock = $( '#bb-bookblock' ),
		$items = $bookblock.children(),
		itemscount = $items.length,
		current = 0,
		bb = $( '#bb-bookblock' ).bookblock( {
			speed : 800,
			perspective : 2000,
			shadowsides	: 0.8,
			shadowflip	: 0.4,
			onendflip : function(old, page, islimit) {
				
				current = page;
				// update toc current
				updatetoc();
				// updatenavigation
				updatenavigation( islimit );
				// initialize jscrollpane on the content div for the new item
				setjsp( 'init' );
				// destroy jscrollpane on the content div for the old item
				setjsp( 'destroy', old );

			}
		} ),
		$navnext = $( '#bb-nav-next' ),
		$navprev = $( '#bb-nav-prev' ).hide(),
		$menuitems = $container.find( 'ul.menu-toc > li' ),
		$tblcontents = $( '#tblcontents' ),
		transendeventnames = {
			'webkittransition': 'webkittransitionend',
			'moztransition': 'transitionend',
			'otransition': 'otransitionend',
			'mstransition': 'mstransitionend',
			'transition': 'transitionend'
		},
		transendeventname = transendeventnames[modernizr.prefixed('transition')],
		supporttransitions = modernizr.csstransitions;

	function init() {

		// initialize jscrollpane on the content div of the first item
		setjsp( 'init' );
		initevents();

	}
	
	function initevents() {

		// add navigation events
		$navnext.on( 'click', function() {
			bb.next();
			return false;
		} );

		$navprev.on( 'click', function() {
			bb.prev();
			return false;
		} );
		
		// add swipe events
		$items.on( {
			'swipeleft'		: function( event ) {
				if( $container.data( 'opened' ) ) {
					return false;
				}
				bb.next();
				return false;
			},
			'swiperight'	: function( event ) {
				if( $container.data( 'opened' ) ) {
					return false;
				}
				bb.prev();
				return false;
			}
		} );

		// show table of contents
		$tblcontents.on( 'click', toggletoc );

		// click a menu item
		$menuitems.on( 'click', function() {

			var $el = $( this ),
				idx = $el.index(),
				jump = function() {
					bb.jump( idx + 1 );
				};
			
			current !== idx ? closetoc( jump ) : closetoc();

			return false;
			
		} );

		// reinit jscrollpane on window resize
		$( window ).on( 'debouncedresize', function() {
			// reinitialise jscrollpane on the content div
			setjsp( 'reinit' );
		} );

	}

	function setjsp( action, idx ) {
		
		var idx = idx === undefined ? current : idx,
			$content = $items.eq( idx ).children( 'div.content' ),
			apijsp = $content.data( 'jsp' );
		
		if( action === 'init' && apijsp === undefined ) {
			$content.jscrollpane({verticalgutter : 0, hidefocus : true });
		}
		else if( action === 'reinit' && apijsp !== undefined ) {
			apijsp.reinitialise();
		}
		else if( action === 'destroy' && apijsp !== undefined ) {
			apijsp.destroy();
		}

	}

	function updatetoc() {
		$menuitems.removeclass( 'menu-toc-current' ).eq( current ).addclass( 'menu-toc-current' );
	}

	function updatenavigation( islastpage ) {
		
		if( current === 0 ) {
			$navnext.show();
			$navprev.hide();
		}
		else if( islastpage ) {
			$navnext.hide();
			$navprev.show();
		}
		else {
			$navnext.show();
			$navprev.show();
		}

	}

	function toggletoc() {
		var opened = $container.data( 'opened' );
		opened ? closetoc() : opentoc();
	}

	function opentoc() {
		$navnext.hide();
		$navprev.hide();
		$container.addclass( 'slideright' ).data( 'opened', true );
	}

	function closetoc( callback ) {

		updatenavigation( current === itemscount - 1 );
		$container.removeclass( 'slideright' ).data( 'opened', false );
		if( callback ) {
			if( supporttransitions ) {
				$container.on( transendeventname, function() {
					$( this ).off( transendeventname );
					callback.call();
				} );
			}
			else {
				callback.call();
			}
		}

	}

	return { init : init };

})();