// Custom reveal.js integration (function(){

var isEnabled = true;

document.querySelector( '.reveal .slides' ).addEventListener( 'mousedown', function( event ) {
        var modifier = ( Reveal.getConfig().zoomKey ? Reveal.getConfig().zoomKey : 'alt' ) + 'Key';

        var zoomPadding = 20;
        var revealScale = Reveal.getScale();

        if( event[ modifier ] && isEnabled ) {
                event.preventDefault();

                var bounds = event.target.getBoundingClientRect();

                zoom.to({
                        x: ( bounds.left * revealScale ) - zoomPadding,
                        y: ( bounds.top * revealScale ) - zoomPadding,
                        width: ( bounds.width * revealScale ) + ( zoomPadding * 2 ),
                        height: ( bounds.height * revealScale ) + ( zoomPadding * 2 ),
                        pan: false
                });
        }
} );

Reveal.addEventListener( 'overviewshown', function() { isEnabled = false; } );
Reveal.addEventListener( 'overviewhidden', function() { isEnabled = true; } );

})();

/*!

* zoom.js 0.3 (modified for use with reveal.js)
* http://lab.hakim.se/zoom-js
* MIT licensed
*
* Copyright (C) 2011-2014 Hakim El Hattab, http://hakim.se
*/

var zoom = (function(){

// The current zoom level (scale)
var level = 1;

// The current mouse position, used for panning
var mouseX = 0,
        mouseY = 0;

// Timeout before pan is activated
var panEngageTimeout = -1,
        panUpdateInterval = -1;

// Check for transform support so that we can fallback otherwise
var supportsTransforms =        'WebkitTransform' in document.body.style ||
                                                        'MozTransform' in document.body.style ||
                                                        'msTransform' in document.body.style ||
                                                        'OTransform' in document.body.style ||
                                                        'transform' in document.body.style;

if( supportsTransforms ) {
        // The easing that will be applied when we zoom in/out
        document.body.style.transition = 'transform 0.8s ease';
        document.body.style.OTransition = '-o-transform 0.8s ease';
        document.body.style.msTransition = '-ms-transform 0.8s ease';
        document.body.style.MozTransition = '-moz-transform 0.8s ease';
        document.body.style.WebkitTransition = '-webkit-transform 0.8s ease';
}

// Zoom out if the user hits escape
document.addEventListener( 'keyup', function( event ) {
        if( level !== 1 && event.keyCode === 27 ) {
                zoom.out();
        }
} );

// Monitor mouse movement for panning
document.addEventListener( 'mousemove', function( event ) {
        if( level !== 1 ) {
                mouseX = event.clientX;
                mouseY = event.clientY;
        }
} );

/**
 * Applies the CSS required to zoom in, prefers the use of CSS3
 * transforms but falls back on zoom for IE.
 *
 * @param {Object} rect
 * @param {Number} scale
 */
function magnify( rect, scale ) {

        var scrollOffset = getScrollOffset();

        // Ensure a width/height is set
        rect.width = rect.width || 1;
        rect.height = rect.height || 1;

        // Center the rect within the zoomed viewport
        rect.x -= ( window.innerWidth - ( rect.width * scale ) ) / 2;
        rect.y -= ( window.innerHeight - ( rect.height * scale ) ) / 2;

        if( supportsTransforms ) {
                // Reset
                if( scale === 1 ) {
                        document.body.style.transform = '';
                        document.body.style.OTransform = '';
                        document.body.style.msTransform = '';
                        document.body.style.MozTransform = '';
                        document.body.style.WebkitTransform = '';
                }
                // Scale
                else {
                        var origin = scrollOffset.x +'px '+ scrollOffset.y +'px',
                                transform = 'translate('+ -rect.x +'px,'+ -rect.y +'px) scale('+ scale +')';

                        document.body.style.transformOrigin = origin;
                        document.body.style.OTransformOrigin = origin;
                        document.body.style.msTransformOrigin = origin;
                        document.body.style.MozTransformOrigin = origin;
                        document.body.style.WebkitTransformOrigin = origin;

                        document.body.style.transform = transform;
                        document.body.style.OTransform = transform;
                        document.body.style.msTransform = transform;
                        document.body.style.MozTransform = transform;
                        document.body.style.WebkitTransform = transform;
                }
        }
        else {
                // Reset
                if( scale === 1 ) {
                        document.body.style.position = '';
                        document.body.style.left = '';
                        document.body.style.top = '';
                        document.body.style.width = '';
                        document.body.style.height = '';
                        document.body.style.zoom = '';
                }
                // Scale
                else {
                        document.body.style.position = 'relative';
                        document.body.style.left = ( - ( scrollOffset.x + rect.x ) / scale ) + 'px';
                        document.body.style.top = ( - ( scrollOffset.y + rect.y ) / scale ) + 'px';
                        document.body.style.width = ( scale * 100 ) + '%';
                        document.body.style.height = ( scale * 100 ) + '%';
                        document.body.style.zoom = scale;
                }
        }

        level = scale;

        if( document.documentElement.classList ) {
                if( level !== 1 ) {
                        document.documentElement.classList.add( 'zoomed' );
                }
                else {
                        document.documentElement.classList.remove( 'zoomed' );
                }
        }
}

/**
 * Pan the document when the mosue cursor approaches the edges
 * of the window.
 */
function pan() {
        var range = 0.12,
                rangeX = window.innerWidth * range,
                rangeY = window.innerHeight * range,
                scrollOffset = getScrollOffset();

        // Up
        if( mouseY < rangeY ) {
                window.scroll( scrollOffset.x, scrollOffset.y - ( 1 - ( mouseY / rangeY ) ) * ( 14 / level ) );
        }
        // Down
        else if( mouseY > window.innerHeight - rangeY ) {
                window.scroll( scrollOffset.x, scrollOffset.y + ( 1 - ( window.innerHeight - mouseY ) / rangeY ) * ( 14 / level ) );
        }

        // Left
        if( mouseX < rangeX ) {
                window.scroll( scrollOffset.x - ( 1 - ( mouseX / rangeX ) ) * ( 14 / level ), scrollOffset.y );
        }
        // Right
        else if( mouseX > window.innerWidth - rangeX ) {
                window.scroll( scrollOffset.x + ( 1 - ( window.innerWidth - mouseX ) / rangeX ) * ( 14 / level ), scrollOffset.y );
        }
}

function getScrollOffset() {
        return {
                x: window.scrollX !== undefined ? window.scrollX : window.pageXOffset,
                y: window.scrollY !== undefined ? window.scrollY : window.pageYOffset
        }
}

return {
        /**
         * Zooms in on either a rectangle or HTML element.
         *
         * @param {Object} options
         *   - element: HTML element to zoom in on
         *   OR
         *   - x/y: coordinates in non-transformed space to zoom in on
         *   - width/height: the portion of the screen to zoom in on
         *   - scale: can be used instead of width/height to explicitly set scale
         */
        to: function( options ) {

                // Due to an implementation limitation we can't zoom in
                // to another element without zooming out first
                if( level !== 1 ) {
                        zoom.out();
                }
                else {
                        options.x = options.x || 0;
                        options.y = options.y || 0;

                        // If an element is set, that takes precedence
                        if( !!options.element ) {
                                // Space around the zoomed in element to leave on screen
                                var padding = 20;
                                var bounds = options.element.getBoundingClientRect();

                                options.x = bounds.left - padding;
                                options.y = bounds.top - padding;
                                options.width = bounds.width + ( padding * 2 );
                                options.height = bounds.height + ( padding * 2 );
                        }

                        // If width/height values are set, calculate scale from those values
                        if( options.width !== undefined && options.height !== undefined ) {
                                options.scale = Math.max( Math.min( window.innerWidth / options.width, window.innerHeight / options.height ), 1 );
                        }

                        if( options.scale > 1 ) {
                                options.x *= options.scale;
                                options.y *= options.scale;

                                magnify( options, options.scale );

                                if( options.pan !== false ) {

                                        // Wait with engaging panning as it may conflict with the
                                        // zoom transition
                                        panEngageTimeout = setTimeout( function() {
                                                panUpdateInterval = setInterval( pan, 1000 / 60 );
                                        }, 800 );

                                }
                        }
                }
        },

        /**
         * Resets the document zoom state to its default.
         */
        out: function() {
                clearTimeout( panEngageTimeout );
                clearInterval( panUpdateInterval );

                magnify( { x: 0, y: 0 }, 1 );

                level = 1;
        },

        // Alias
        magnify: function( options ) { this.to( options ) },
        reset: function() { this.out() },

        zoomLevel: function() {
                return level;
        }
}

})();