/*! Deck JS - deck.scale Copyright © 2011-2012 Caleb Troughton Dual licensed under the MIT license and GPL license. github.com/imakewebthings/deck.js/blob/master/MIT-license.txt github.com/imakewebthings/deck.js/blob/master/GPL-license.txt */

/* This module adds automatic scaling to the deck. Slides are scaled down using CSS transforms to fit within the deck container. If the container is big enough to hold the slides without scaling, no scaling occurs. The user can disable and enable scaling with a keyboard shortcut.

Note: CSS transforms may make Flash videos render incorrectly. Presenters that need to use video may want to disable scaling to play them. HTML5 video works fine. */ (function($, deck, window, undefined) {

var $d = $(document),
$w = $(window),
baseHeight, // Value to scale against
timer, // Timeout id for debouncing
rootSlides,

/*
Internal function to do all the dirty work of scaling the slides.
*/
scaleDeck = function() {
        var opts = $[deck]('getOptions'),
        obh = opts.baseHeight,
        $container = $[deck]('getContainer'),
        baseHeight = obh ? obh : $container.height();

        // Scale each slide down if necessary (but don't scale up)
        $.each(rootSlides, function(i, $slide) {
                var slideHeight = $slide.innerHeight(),
                $scaler = $slide.find('.' + opts.classes.scaleSlideWrapper),
                scale = $container.hasClass(opts.classes.scale) ?
                        baseHeight / slideHeight :
                        1;

                $.each('Webkit Moz O ms Khtml'.split(' '), function(i, prefix) {
                        if (scale === 1) {
                                $scaler.css(prefix + 'Transform', '');
                        }
                        else {
                                $scaler.css(prefix + 'Transform', 'scale(' + scale + ')');
                        }
                });
        });
}

/*
Extends defaults/options.

options.classes.scale
        This class is added to the deck container when scaling is enabled.
        It is enabled by default when the module is included.

options.classes.scaleSlideWrapper
        Scaling is done using a wrapper around the contents of each slide. This
        class is applied to that wrapper.

options.keys.scale
        The numeric keycode used to toggle enabling and disabling scaling.

options.baseHeight
        When baseHeight is falsy, as it is by default, the deck is scaled in
        proportion to the height of the deck container. You may instead specify
        a height as a number of px, and slides will be scaled against this
        height regardless of the container size.

options.scaleDebounce
        Scaling on the browser resize event is debounced. This number is the
        threshold in milliseconds. You can learn more about debouncing here:
        http://unscriptable.com/index.php/2009/03/20/debouncing-javascript-methods/

*/
$.extend(true, $[deck].defaults, {
        classes: {
                scale: 'deck-scale',
                scaleSlideWrapper: 'deck-slide-scaler'
        },

        keys: {
                scale: 83 // s
        },

        baseHeight: null,
        scaleDebounce: 200
});

/*
jQuery.deck('disableScale')

Disables scaling and removes the scale class from the deck container.
*/
$[deck]('extend', 'disableScale', function() {
        $[deck]('getContainer').removeClass($[deck]('getOptions').classes.scale);
        scaleDeck();
});

/*
jQuery.deck('enableScale')

Enables scaling and adds the scale class to the deck container.
*/
$[deck]('extend', 'enableScale', function() {
        $[deck]('getContainer').addClass($[deck]('getOptions').classes.scale);
        scaleDeck();
});

/*
jQuery.deck('toggleScale')

Toggles between enabling and disabling scaling.
*/
$[deck]('extend', 'toggleScale', function() {
        var $c = $[deck]('getContainer');
        $[deck]($c.hasClass($[deck]('getOptions').classes.scale) ?
                'disableScale' : 'enableScale');
});

$d.bind('deck.init', function() {
        var opts = $[deck]('getOptions'),
        slideTest = $.map([
                opts.classes.before,
                opts.classes.previous,
                opts.classes.current,
                opts.classes.next,
                opts.classes.after
        ], function(el, i) {
                return '.' + el;
        }).join(', ');

        // Build top level slides array
        rootSlides = [];
        $.each($[deck]('getSlides'), function(i, $el) {
                if (!$el.parentsUntil(opts.selectors.container, slideTest).length) {
                        rootSlides.push($el);
                }
        });

        // Use a wrapper on each slide to handle content scaling
        $.each(rootSlides, function(i, $slide) {
                $slide.children().wrapAll('<div class="' + opts.classes.scaleSlideWrapper + '"/>');
        });

        // Debounce the resize scaling
        $w.unbind('resize.deckscale').bind('resize.deckscale', function() {
                window.clearTimeout(timer);
                timer = window.setTimeout(scaleDeck, opts.scaleDebounce);
        })
        // Scale once on load, in case images or something change layout
        .unbind('load.deckscale').bind('load.deckscale', scaleDeck);

        // Bind key events
        $d.unbind('keydown.deckscale').bind('keydown.deckscale', function(e) {
                if (e.which === opts.keys.scale || $.inArray(e.which, opts.keys.scale) > -1) {
                        $[deck]('toggleScale');
                        e.preventDefault();
                }
        });

        // Enable scale on init
        $[deck]('enableScale');
});

})(jQuery, 'deck', this);