/**********************************************************************
* 
*
*
**********************************************************************/

// A stub image, also here for documentation...
var STUB_IMAGE_DATA = {
	// Entity GID...
	id: 'STUB-GID',

	// Entity type
	//
	// can be:
	// 	- 'image'
	// 	- 'group'
	type: 'image',

	// Entity state
	//
	// can be:
	// 	- 'single'
	// 	- 'grouped'
	// 	- 'hidden'
	// 	- ...
	state: 'single',

	// Creation time...
	ctime: 0,

	// Original path...
	path: './images/sizes/900px/SIZE.jpg',

	// Previews...
	// NOTE: the actual values depend on specific image and can be
	// 		any size...
	preview: {
		'150px': './images/sizes/150px/SIZE.jpg',
		'350px': './images/sizes/350px/SIZE.jpg',
		'900px': './images/sizes/900px/SIZE.jpg',
	},

	// Classes
	// XXX currently unused...
	classes: '',

	// Image orientation (optional)
	//
	// can be:
	// 	- null/undefined	- same as 0
	// 	- 0 (default)		- load as-is
	// 	- 90				- rotate 90deg CW
	// 	- 180				- rotate 180deg CW
	// 	- 270				- rotate 270deg CW (90deg CCW)
	//
	// NOTE: use orientationExif2ImageGrid(..) to convert from EXIF 
	// 		orientation format to ImageGrid format...
	orientation: 0,

	// Image flip state (optional)
	//
	// can be:
	// 	- null/undefined
	// 	- array
	//
	// can contain:
	// 	- 'vertical'
	// 	- 'horizontal'
	//
	// NOTE: use orientationExif2ImageGrid(..) to convert from EXIF 
	// 		orientation format to ImageGrid format...
	flipped: null,

	// Image comment (optional)
	//
	// can be:
	// 	- null/undefined
	// 	- string
	comment: null,

	// List of image tags (optional)
	//
	// can be:
	// 	- null/undefined
	// 	- array
	tags: null,
}


// List of function that update image state...
//
// these are called by updateImage(..) after the image is created.
//
// each function must be of the form:
// 	updateImage(gid, image) -> image
//
var IMAGE_UPDATERS = []



/*********************************************************************/

// XXX Constructors...


/*********************************************************************/

// Run all the image update functions registered in IMAGE_UPDATERS, on 
// an image...
//
function updateImageIndicators(gid, image){
	gid = gid == null ? getImageGID() : gid
	image = image == null ? getImage() : $(image)

	IMAGE_UPDATERS.forEach(function(update){
		update(gid, image)
	})

	return image
}


// helper...
function _loadImagePreviewURL(image, url){
	// pre-cache and load image...
	// NOTE: this will make images load without a blackout...
	var img = new Image()
	img.onload = function(){
		image.css({
				'background-image': 'url("'+ url +'")',
			})
	}
	img.src = url
	return img
}


// Update an image element
//
// NOTE: care must be taken to reset ALL attributes an image can have,
// 		a common bug if this is not done correctly, is that some settings
// 		may leak to newly loaded images...
function updateImage(image, gid, size, sync){
	image = image == null ? getImage() : $(image)
	sync = sync == null ? CONFIG.load_img_sync : sync
	var old_gid = getImageGID(image)

	// same image -- update...
	if(old_gid == gid || gid == null){
		gid = old_gid

	// reuse for different image -- reconstruct...
	} else {
		// remove old marks...
		if(typeof(old_gid) == typeof('str')){
			getImageMarks(old_gid).remove()
		}
		// reset gid...
		image
			.attr('gid', JSON.stringify(gid))
			.css({
				// clear the old preview...
				'background-image': '',
			})
	}
	size = size == null ? getVisibleImageSize('max') : size

	// get the image data...
	var img_data = IMAGES[gid]
	if(img_data == null){
		img_data = STUB_IMAGE_DATA
	}

	/* XXX does not seem to be needing this...
	// set the current class...
	if(gid == DATA.current){
		image.addClass('current')
	} else {
		image.removeClass('current')
	}
	*/

	// preview...
	var p_url = getBestPreview(gid, size).url

	// update the preview if it's a new image or...
	if(old_gid != gid 
			// the new preview (purl) is different to current...
			|| image.css('background-image').indexOf(encodeURI(p_url)) < 0){
		// sync load...
		if(sync){
			_loadImagePreviewURL(image, p_url)

		// async load...
		} else {
			// NOTE: storing the url in .data() makes the image load the 
			// 		last requested preview and in a case when we manage to 
			// 		call updateImage(...) on the same element multiple times 
			// 		before the previews get loaded...
			// 		...setting the data().loading is sync while loading an 
			// 		image is not, and if several loads are done in sequence
			// 		there is no guarantee that they will happen in the same
			// 		order as requested...
			image.data().loading = p_url
			setTimeout(function(){ 
				_loadImagePreviewURL(image, image.data().loading)
			}, 0)
		}
	}

	// main attrs...
	image
		.attr({
			order: DATA.order.indexOf(gid),
			orientation: img_data.orientation == null ? 0 : img_data.orientation,
		})

	// flip...
	setImageFlipState(image, img_data.flipped == null ? [] : img_data.flipped)

	// NOTE: this only has effect on non-square image blocks...
	correctImageProportionsForRotation(image)

	// marks and other indicators...
	updateImageIndicators(gid, image)

	return image
}


// Same as updateImage(...) but will update all loaded images.
//
// If list is passed this will update only the images in the list. The
// list can contain either gids or image elements.
//
// If CONFIG.update_sort_enabled is set, this will prioritize images by
// distance from current image, loading the closest images first...
//
// If CONFIG.update_sync is set, this will run asynchronously.
function updateImages(list, size, cmp){
	var deferred = $.Deferred()

	function _worker(){
		list = list == null ? $('.image') : $(list)
		size = size == null ? getVisibleImageSize('max') : size

		function _update(_, e){
			var img = typeof(e) == typeof('str') ? getImage(e) : $(e)
			if(img.length > 0){
				updateImage(img, null, size)
			}
		}

		// sorted run...
		if(CONFIG.update_sort_enabled && cmp != false){
			cmp = cmp == null ? 
					makeGIDDistanceCmp(getImageGID(), function(e){ 
						return typeof(e) == typeof('str') ? e : getImageGID(e) 
					}) 
					// XXX this is more correct but is slow...
					//makeGIDRibbonDistanceCmp(getImageGID(), getImageGID) 
				: cmp
			deferred.resolve(list
				// sort images by distance from current, so as to update what 
				// the user is looking at first...
				.sort(cmp)
				.map(_update))

		// do a fast run w.o. sorting images...
		} else {
			deferred.resolve(list.map(_update))
		}
	}

	if(CONFIG.update_sync){
		_worker()
	} else {
		setTimeout(_worker, 0)
	}

	return deferred
}


// Compensate for viewer proportioned and rotated images.
//
// This will set the margins so as to make the rotated image offset the
// same space as it is occupying visually...
//
// NOTE: this is not needed for square image blocks.
// NOTE: if an image block is square, this will remove the margins.
function correctImageProportionsForRotation(images, container){
	container = container == null ? $('.viewer') : container

	var W = container.innerWidth()
	var H = container.innerHeight()

	var viewer_p = W > H ? 'landscape' : 'portrait'

	return $(images).each(function(i, e){
		var image = $(this)
		// orientation...
		var o = image.attr('orientation')
		o = o == null ? 0 : o
		var w = image.outerWidth()
		var h = image.outerHeight()

		// non-square image...
		if(w != h){

			var image_p = w > h ? 'landscape' : 'portrait'

			// when the image is turned 90deg/270deg and its 
			// proportions are the same as the screen...
			if((o == 90 || o == 270) && image_p == viewer_p){
				image.css({
					width: h,
					height: w,
				})
				image.css({
					'margin-top': -((w - h)/2),
					'margin-bottom': -((w - h)/2),
					'margin-left': (w - h)/2,
					'margin-right': (w - h)/2,
				})

			} else if((o == 0 || o == 180) && image_p != viewer_p){
				image.css({
					width: h,
					height: w,
				})
				image.css({
					'margin': '',
				})
			}

		// square image...
		} else {
			image.css({
				'margin': '',
			})
		}
	})
}



/**********************************************************************
* vim:set ts=4 sw=4 :                                                */