/**
 * tiltfx.js
 * http://www.codrops.com
 *
 * Licensed under the MIT license.
 * http://www.opensource.org/licenses/mit-license.php
 *
 * Copyright 2015, Codrops
 * http://www.codrops.com
 */
;(function(window) {

    'use strict';
    /**
     * **************************************************************************
     * utils
     * **************************************************************************
     */
        // from https://gist.github.com/desandro/1866474
    var lastTime = 0;
    var prefixes = 'webkit moz ms o'.split(' ');
    // get unprefixed rAF and cAF, if present
    var requestAnimationFrame = window.requestAnimationFrame;
    var cancelAnimationFrame = window.cancelAnimationFrame;
    // loop through vendor prefixes and get prefixed rAF and cAF
    var prefix;
    for( var i = 0; i < prefixes.length; i++ ) {
        if ( requestAnimationFrame && cancelAnimationFrame ) {
            break;
        }
        prefix = prefixes[i];
        requestAnimationFrame = requestAnimationFrame || window[ prefix + 'RequestAnimationFrame' ];
        cancelAnimationFrame  = cancelAnimationFrame  || window[ prefix + 'CancelAnimationFrame' ] ||
            window[ prefix + 'CancelRequestAnimationFrame' ];
    }

    // fallback to setTimeout and clearTimeout if either request/cancel is not supported
    if ( !requestAnimationFrame || !cancelAnimationFrame ) {
        requestAnimationFrame = function( callback, element ) {
            var currTime = new Date().getTime();
            var timeToCall = Math.max( 0, 16 - ( currTime - lastTime ) );
            var id = window.setTimeout( function() {
                callback( currTime + timeToCall );
            }, timeToCall );
            lastTime = currTime + timeToCall;
            return id;
        };

        cancelAnimationFrame = function( id ) {
            window.clearTimeout( id );
        };
    }

    function extend( a, b ) {
        for( var key in b ) {
            if( b.hasOwnProperty( key ) ) {
                a[key] = b[key];
            }
        }
        return a;
    }

    // from http://www.quirksmode.org/js/events_properties.html#position
    function getMousePos(e) {
        var posx = 0;
        var posy = 0;
        if (!e) var e = window.event;
        if (e.pageX || e.pageY) 	{
            posx = e.pageX;
            posy = e.pageY;
        }
        else if (e.clientX || e.clientY) 	{
            posx = e.clientX + document.body.scrollLeft
                + document.documentElement.scrollLeft;
            posy = e.clientY + document.body.scrollTop
                + document.documentElement.scrollTop;
        }
        return {
            x : posx,
            y : posy
        }
    }

    // from http://www.sberry.me/articles/javascript-event-throttling-debouncing
    function throttle(fn, delay) {
        var allowSample = true;

        return function(e) {
            if (allowSample) {
                allowSample = false;
                setTimeout(function() { allowSample = true; }, delay);
                fn(e);
            }
        };
    }

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

    /**
     * TiltFx fn
     */
    function TiltFx(el, options) {
        this.el = el;
        this.options = extend( {}, this.options );
        extend( this.options, options );
        this._init();
        this._initEvents();
    }

    /**
     * TiltFx options.
     */
    TiltFx.prototype.options = {
        // number of extra image elements (div with background-image) to add to the DOM - min:1, max:5 (for a higher number, it's recommended to remove the transitions of .tilt__front in the stylesheet.
        extraImgs : 2,
        // the opacity value for all the image elements.
        opacity : 0.7,
        // by default the first layer does not move.
        bgfixed : true,
        // image element's movement configuration
        movement : {
            perspective : 1500, // perspective value
            translateX : -5, // a relative movement of -10px to 10px on the x-axis (setting a negative value reverses the direction)
            translateY : -5, // a relative movement of -10px to 10px on the y-axis
            translateZ : 10, // a relative movement of -20px to 20px on the z-axis (perspective value must be set). Also, this specific translation is done when the mouse moves vertically.
            rotateX : 2, // a relative rotation of -2deg to 2deg on the x-axis (perspective value must be set)
            rotateY : 2, // a relative rotation of -2deg to 2deg on the y-axis (perspective value must be set)
            rotateZ : 0 // z-axis rotation; by default there's no rotation on the z-axis (perspective value must be set)
        }
    }

    /**
     * Initialize: build the necessary structure for the image elements and replace it with the HTML img element.
     */
    TiltFx.prototype._init = function() {
        this.tiltWrapper = document.createElement('div');
        this.tiltWrapper.className = 'tilt';

        // main image element.
        this.tiltImgBack = document.createElement('div');
        this.tiltImgBack.className = 'tilt__back';
        this.tiltImgBack.style.backgroundImage = 'url(' + this.el.src + ')';
        this.tiltWrapper.appendChild(this.tiltImgBack);

        // image elements limit.
        if( this.options.extraImgs < 1 ) {
            this.options.extraImgs = 1;
        }
        else if( this.options.extraImgs > 5 ) {
            this.options.extraImgs = 5;
        }

        if( !this.options.movement.perspective ) {
            this.options.movement.perspective = 0;
        }

        // add the extra image elements.
        this.imgElems = [];
        for(var i = 0; i < this.options.extraImgs; ++i) {
            var el = document.createElement('div');
            el.className = 'tilt__front';
            el.style.backgroundImage = 'url(' + this.el.src + ')';
            el.style.opacity = this.options.opacity;
            this.tiltWrapper.appendChild(el);
            this.imgElems.push(el);
        }

        if( !this.options.bgfixed ) {
            this.imgElems.push(this.tiltImgBack);
            ++this.options.extraImgs;
        }

        // add it to the DOM and remove original img element.
        this.el.parentNode.insertBefore(this.tiltWrapper, this.el);
        this.el.parentNode.removeChild(this.el);

        // tiltWrapper properties: width/height/left/top
        this.view = { width : this.tiltWrapper.offsetWidth, height : this.tiltWrapper.offsetHeight };
    };

    /**
     * Initialize the events on the main wrapper.
     */
    TiltFx.prototype._initEvents = function() {
        var self = this,
            moveOpts = self.options.movement;

        // mousemove event..
        this.tiltWrapper.addEventListener('mousemove', function(ev) {
            requestAnimationFrame(function() {
                // mouse position relative to the document.
                var mousepos = getMousePos(ev),
                    // document scrolls.
                    docScrolls = {left : document.body.scrollLeft + document.documentElement.scrollLeft, top : document.body.scrollTop + document.documentElement.scrollTop},
                    bounds = self.tiltWrapper.getBoundingClientRect(),
                    // mouse position relative to the main element (tiltWrapper).
                    relmousepos = {
                        x : mousepos.x - bounds.left - docScrolls.left,
                        y : mousepos.y - bounds.top - docScrolls.top
                    };

                // configure the movement for each image element.
                for(var i = 0, len = self.imgElems.length; i < len; ++i) {
                    var el = self.imgElems[i],
                        rotX = moveOpts.rotateX ? 2 * ((i+1)*moveOpts.rotateX/self.options.extraImgs) / self.view.height * relmousepos.y - ((i+1)*moveOpts.rotateX/self.options.extraImgs) : 0,
                        rotY = moveOpts.rotateY ? 2 * ((i+1)*moveOpts.rotateY/self.options.extraImgs) / self.view.width * relmousepos.x - ((i+1)*moveOpts.rotateY/self.options.extraImgs) : 0,
                        rotZ = moveOpts.rotateZ ? 2 * ((i+1)*moveOpts.rotateZ/self.options.extraImgs) / self.view.width * relmousepos.x - ((i+1)*moveOpts.rotateZ/self.options.extraImgs) : 0,
                        transX = moveOpts.translateX ? 2 * ((i+1)*moveOpts.translateX/self.options.extraImgs) / self.view.width * relmousepos.x - ((i+1)*moveOpts.translateX/self.options.extraImgs) : 0,
                        transY = moveOpts.translateY ? 2 * ((i+1)*moveOpts.translateY/self.options.extraImgs) / self.view.height * relmousepos.y - ((i+1)*moveOpts.translateY/self.options.extraImgs) : 0,
                        transZ = moveOpts.translateZ ? 2 * ((i+1)*moveOpts.translateZ/self.options.extraImgs) / self.view.height * relmousepos.y - ((i+1)*moveOpts.translateZ/self.options.extraImgs) : 0;

                    el.style.WebkitTransform = 'perspective(' + moveOpts.perspective + 'px) translate3d(' + transX + 'px,' + transY + 'px,' + transZ + 'px) rotate3d(1,0,0,' + rotX + 'deg) rotate3d(0,1,0,' + rotY + 'deg) rotate3d(0,0,1,' + rotZ + 'deg)';
                    el.style.transform = 'perspective(' + moveOpts.perspective + 'px) translate3d(' + transX + 'px,' + transY + 'px,' + transZ + 'px) rotate3d(1,0,0,' + rotX + 'deg) rotate3d(0,1,0,' + rotY + 'deg) rotate3d(0,0,1,' + rotZ + 'deg)';
                }
            });
        });

        // reset all when mouse leaves the main wrapper.
        this.tiltWrapper.addEventListener('mouseleave', function(ev) {
            setTimeout(function() {
                for(var i = 0, len = self.imgElems.length; i < len; ++i) {
                    var el = self.imgElems[i];
                    el.style.WebkitTransform = 'perspective(' + moveOpts.perspective + 'px) translate3d(0,0,0) rotate3d(1,1,1,0deg)';
                    el.style.transform = 'perspective(' + moveOpts.perspective + 'px) translate3d(0,0,0) rotate3d(1,1,1,0deg)';
                }
            }, 60);

        });

        // window resize
        window.addEventListener('resize', throttle(function(ev) {
            // recalculate tiltWrapper properties: width/height/left/top
            self.view = { width : self.tiltWrapper.offsetWidth, height : self.tiltWrapper.offsetHeight };
        }, 50));
    };

    function init() {

        // search for imgs with the class "tilt-effect"
        [].slice.call(document.querySelectorAll('img.tilt-effect')).forEach(function(img) {
            new TiltFx(img, JSON.parse(img.getAttribute('data-tilt-options')));
        });
    }
    init();

    window.TiltFx = TiltFx;

})(window);