window.requestAnimFrame = (function(){
  return  window.requestAnimationFrame       ||
          window.webkitRequestAnimationFrame ||
          window.mozRequestAnimationFrame    ||
          function( callback ){
            window.setTimeout(callback, 1000 / 60);
          };
})();

window.cancelRequestAnimFrame = ( function() {
    return window.cancelAnimationFrame          ||
        window.webkitCancelRequestAnimationFrame    ||
        window.mozCancelRequestAnimationFrame       ||
        window.oCancelRequestAnimationFrame     ||
        window.msCancelRequestAnimationFrame        ||
        clearTimeout
} )();


var Intense = (function() {

    'use strict';

    var KEYCODE_ESC = 27;

    // Track both the current and destination mouse coordinates
    // Destination coordinates are non-eased actual mouse coordinates
    var mouse = { xCurr:0, yCurr:0, xDest: 0, yDest: 0 };

    var horizontalOrientation = true;

    // Holds the animation frame id.
    var looper;
  
    // Current position of scrolly element
    var lastPosition, currentPosition = 0;
    
    var sourceDimensions, target;
    var targetDimensions = { w: 0, h: 0 };
  
    var container;
    var containerDimensions = { w: 0, h:0 };
    var overflowArea = { x: 0, y: 0 };

    // Overflow variable before screen is locked.
    var overflowValue;

    /* -------------------------
    /*          UTILS
    /* -------------------------*/

    // Soft object augmentation
    function extend( target, source ) {

        for ( var key in source )

            if ( !( key in target ) )

                target[ key ] = source[ key ];

        return target;
    }

    // Applys a dict of css properties to an element
    function applyProperties( target, properties ) {

      for( var key in properties ) {
        target.style[ key ] = properties[ key ];
      }
    }

    // Returns whether target a vertical or horizontal fit in the page.
    // As well as the right fitting width/height of the image.
    function getFit( 

      source ) {

      var heightRatio = window.innerHeight / source.h;

      if( (source.w * heightRatio) > window.innerWidth ) {
        return { w: source.w * heightRatio, h: source.h * heightRatio, fit: true };
      } else {
        var widthRatio = window.innerWidth / source.w;
        return { w: source.w * widthRatio, h: source.h * widthRatio, fit: false };
      }
    }

    /* -------------------------
    /*          APP
    /* -------------------------*/

    function startTracking( passedElements ) {

      var i;

      // If passed an array of elements, assign tracking to all.
      if ( passedElements.length ) {

        // Loop and assign
        for( i = 0; i < passedElements.length; i++ ) {
          track( passedElements[ i ] );
        }

      } else {
          track( passedElements );
      }
    }

    function track( element ) {

      // Element needs a src at minumun.
      if( element.getAttribute( 'data-image') || element.src ) {
        element.addEventListener( 'click', function() {
          init( this );
        }, false );
      }
    }
  
    function start() { 
      loop();
    }
   
    function stop() {
      cancelRequestAnimFrame( looper );
    }

    function loop() {
        looper = requestAnimFrame(loop);
        positionTarget();      
    }

    // Lock scroll on the document body.
    function lockBody() {

      overflowValue = document.body.style.overflow;
      document.body.style.overflow = 'hidden';
    }

    // Unlock scroll on the document body.
    function unlockBody() {
      document.body.style.overflow = overflowValue;
    }

    function createViewer( title, caption ) {

      /*
       *  Container
       */
      var containerProperties = {
        'backgroundColor': 'rgba(0,0,0,0.8)',
        'width': '100%',
        'height': '100%',
        'position': 'fixed',
        'top': '0px',
        'left': '0px',
        'overflow': 'hidden',
        'zIndex': '999999',
        'margin': '0px',
        'webkitTransition': 'opacity 150ms cubic-bezier( 0, 0, .26, 1 )',
        'MozTransition': 'opacity 150ms cubic-bezier( 0, 0, .26, 1 )',
        'transition': 'opacity 150ms cubic-bezier( 0, 0, .26, 1 )',
        'opacity': '0'
      }
      container = document.createElement( 'figure' );
      container.appendChild( target );
      applyProperties( container, containerProperties );

      var imageProperties = {
        'cursor': 'url( "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADIAAAAyCAYAAAAeP4ixAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAyRpVFh0WE1MOmNvbS5hZG9iZS54bXAAAAAAADw/eHBhY2tldCBiZWdpbj0i77u/IiBpZD0iVzVNME1wQ2VoaUh6cmVTek5UY3prYzlkIj8+IDx4OnhtcG1ldGEgeG1sbnM6eD0iYWRvYmU6bnM6bWV0YS8iIHg6eG1wdGs9IkFkb2JlIFhNUCBDb3JlIDUuMy1jMDExIDY2LjE0NTY2MSwgMjAxMi8wMi8wNi0xNDo1NjoyNyAgICAgICAgIj4gPHJkZjpSREYgeG1sbnM6cmRmPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5LzAyLzIyLXJkZi1zeW50YXgtbnMjIj4gPHJkZjpEZXNjcmlwdGlvbiByZGY6YWJvdXQ9IiIgeG1sbnM6eG1wPSJodHRwOi8vbnMuYWRvYmUuY29tL3hhcC8xLjAvIiB4bWxuczp4bXBNTT0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wL21tLyIgeG1sbnM6c3RSZWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20veGFwLzEuMC9zVHlwZS9SZXNvdXJjZVJlZiMiIHhtcDpDcmVhdG9yVG9vbD0iQWRvYmUgUGhvdG9zaG9wIENTNiAoTWFjaW50b3NoKSIgeG1wTU06SW5zdGFuY2VJRD0ieG1wLmlpZDo3Q0IyNDI3M0FFMkYxMUUzOEQzQUQ5NTMxMDAwQjJGRCIgeG1wTU06RG9jdW1lbnRJRD0ieG1wLmRpZDo3Q0IyNDI3NEFFMkYxMUUzOEQzQUQ5NTMxMDAwQjJGRCI+IDx4bXBNTTpEZXJpdmVkRnJvbSBzdFJlZjppbnN0YW5jZUlEPSJ4bXAuaWlkOjdDQjI0MjcxQUUyRjExRTM4RDNBRDk1MzEwMDBCMkZEIiBzdFJlZjpkb2N1bWVudElEPSJ4bXAuZGlkOjdDQjI0MjcyQUUyRjExRTM4RDNBRDk1MzEwMDBCMkZEIi8+IDwvcmRmOkRlc2NyaXB0aW9uPiA8L3JkZjpSREY+IDwveDp4bXBtZXRhPiA8P3hwYWNrZXQgZW5kPSJyIj8+soZ1WgAABp5JREFUeNrcWn9MlVUY/u4dogIapV0gQ0SUO4WAXdT8B5ULc6uFgK3MLFxzFrQFZMtaed0oKTPj1x8EbbZZK5fNCdLWcvxQ+EOHyAQlBgiIVFxAJuUF7YrQ81zOtU+8F+Pe78K1d3s5537f+fE8nPec7z3vOSpJIRkbGwtEEgtdBdVCl0AXQr2hKqgJeg16BdoCrYNWqVSqbif7VQT8YqgB2jTmuDSJNoIcJUJVOVg5EsmH0Oehaj4bGRkZ6uvra2xvb29oamrqbGxs7K2vrx/s7Oy8yffBwcFzdTqdb0REhF9YWFhwSEhIpEajifDw8PAWzY5Cj0GzMUoNUx0R1RQJaJAcgKaw7ujo6O2urq7qysrKioyMjHNDQ0OjU2nP29tbnZ+fv1qv18cFBQWtU6vVs9gN9BvobhDqU5wIKryA5CuoLwj83dzc/NOePXuOlpSUXFNijiUlJS3ct2/fiytWrHgOhGbj0SD0dZD5UREiKOiJJA+axt9Go7F2165deUeOHOmVXCBbt271y8nJyfD3939aPCqCZoCQ2WEiKOQj7HYjzejUqVNFcXFxJdI0SEVFRdKGDRtShbmd5HwEGZM9IupJSHiJBjaazebr2dnZmdNFgsK+2Cf7JgZiEZhsimoSc/oZqh8eHjamp6fvPnTo0O/SDMiOHTsWFRQUHPDy8vLnQEGflZvZpKaFl4WcE7du3epPTU19+/Dhwz3SDMr27dsDioqKcufMmfM45wyIpD3QtPBiC0lgTowcPHgwa6ZJUIiBWIgJP1OB8aVJTQsFnkDSxCUWk60gPj6+VHIjKS8vT8TcSRdLcxhG5g+bpoWH3yF5ube3tw7L33uSGwqW/8/8/Pzoz30PItvuMy080HEZx/CZDQZDgeSmQmzESKwC870jgodcWhPhJx0LDw8vlNxYLl269Cb8Nfp5NP2kuyMiPM8EfvTodkhuLsQoJn4C/VG5ab3CfHd3d41SvpMrhRiBtVrgf01OZBv/nIRID4nIsG6xzBGxs7vK/YSvr2/SVF3xiYL55bVgwYJZp0+f/nOycuvXr38E+xczvOibjvTDLcDg4OBx7GfoD4ZwRPR8gUYbnCUBF3wuHMtPy8rKcmJjY33tleM7lqmpqdnPOo70RazAfNHapFrssaWOjo6Lzg43vj2zPT09febNm7ektLT0C1tk+IzvWIZlWcfR/oC5UWSjSCSUudbW1qvOEqmqqhrcvHnzOzdu3Lhii4ycBMuwLOs42t/ly5etmLUkEsJcbW3tbwq5ETbJ2CLBss70dfbsWSvmpZzsnJTzo6KiEhoaGoaVWlXkwE0mkyXk4+PjE6gUCUpMTMz86urq48gOkIjFWYHfEqf0EkkyJ06cyCMB/iah5OTkTCVIUDQajQf8wl+QNaune/2/c+eOS9olkb+YiYyM9FJ6NGhaHA2OBJV5e6uZI6LVaq2YTSTSz9zatWsfc8X84JzYtGlTJtXeauaorFy5cr7IXieRdubWrFnzpCtIJCYmWpZYKvNKksE/34q5g0RamQsNDV3sKhLy74ySZJYtW2bF3EIidZaFeOnSp5wl0t/fb4aYbJGwRYZlWcfR/mSYL8idRhOcxuTpdBoHBgZuY5Pk0LfrPqdRnE8080Fubm60Aru34QeRoLCMoyQoxCpItFnnCIVBB2kj5GHZj8iw/iDfWJHIaGBgYAyj4u5OghiBdZ00fqby9V0iMK8rSMoYMGZo392JECOwehAztHNipPFjxiGw0UnYuXPnInclQWzEKI0fCH1kL9JoCdAZjcZzAQEB77sjkZ6env3YjK22G6AT8i7DkSzI8KS7kSAmQWJQYL3HabwrjKVK4mQKX9w0g8EQ6i4k9u7dqyUm8TNNYJVsmpbMxL5EkuouxwopKSn+xcXFeeJYoRgkUmVYJyXirgc9ldBnbB302NxYiYJcGc6wgcLCwvysrCztTJgT+xYkzhCTvUPR//9hqBgZkxiZYjao1+vf4vLH4XalKbEP9iVIFIuRME2K9b92MOHCAEOdZS66MJAAAp5iiX0DBI4+ANfUiIhKvMLxOfRVSXaFA2ZQnpmZWefIFY68vLxVMNf4CVc4vuV3wiVXOCZUjkLygXTvpRoTL9Uw9NrS0tJVX1/fc/78+ettbW2WIPXy5cvnRkdHP6rT6QK0Wm0QNkXhGo0mUrjikvTvpZpPQODCFLA4bw6ya06/OnHNqXnGrjnZIyWNXzyjC0GPYIk0fvHM+h+XXzxjnOCcNH7x7KqT/VrSfwQYAOAcX9HTDttYAAAAAElFTkSuQmCC" ) 25 25, no-drop'
      }
      applyProperties( target, imageProperties );

      /*
       *  Caption Container
       */
      var captionContainerProperties = {
        'fontFamily': 'Georgia, Times, "Times New Roman", serif',
        'position': 'fixed',
        'bottom': '0px',
        'left': '0px',
        'padding': '20px',
        'color': '#fff',
        'wordSpacing': '0.2px',
        'webkitFontSmoothing': 'antialiased',
        'textShadow': '-1px 0px 1px rgba(0,0,0,0.4)'
      }
      var captionContainer = document.createElement( 'figcaption' );
      applyProperties( captionContainer, captionContainerProperties );

      /*
       *  Caption Title
       */
      if ( title ) {
        var captionTitleProperties = {
          'margin': '0px',
          'padding': '0px',
          'fontWeight': 'normal',
          'fontSize': '40px',
          'letterSpacing': '0.5px',
          'lineHeight': '35px',
          'textAlign': 'left'
        }
        var captionTitle = document.createElement( 'h1' );
        applyProperties( captionTitle, captionTitleProperties );
        captionTitle.innerHTML = title;
        captionContainer.appendChild( captionTitle );
      }

      if ( caption ) {
        var captionTextProperties = {
          'margin': '0px',
          'padding': '0px',
          'fontWeight': 'normal',
          'fontSize': '20px',
          'letterSpacing': '0.1px',
          'maxWidth': '500px',
          'textAlign': 'left',
          'background': 'none',
          'marginTop': '5px'
        }
        var captionText = document.createElement( 'h2' );
        applyProperties( captionText, captionTextProperties );
        captionText.innerHTML = caption;
        captionContainer.appendChild( captionText );
      }

      container.appendChild( captionContainer );

      setDimensions();

      mouse.xCurr = mouse.xDest = window.innerWidth / 2;
      mouse.yCurr = mouse.yDest = window.innerHeight / 2;
      
      document.body.appendChild( container );
      setTimeout( function() {
        container.style[ 'opacity' ] = '1';
      }, 10);
    }

    function removeViewer() {

      unlockBody();
      unbindEvents();
      stop();
      document.body.removeChild( container );
    }

    function setDimensions() {

      // Manually set height to stop bug where 
      var imageDimensions = getFit( sourceDimensions );
      target.width = imageDimensions.w;
      target.height = imageDimensions.h;
      horizontalOrientation = imageDimensions.fit;

      targetDimensions = { w: target.width, h: target.height };
      containerDimensions = { w: window.innerWidth, h: window.innerHeight };
      overflowArea = {x: containerDimensions.w - targetDimensions.w, y: containerDimensions.h - targetDimensions.h};

    }

    function init( element ) {

      var imageSource = element.getAttribute( 'data-image') || element.src;
      var title = element.getAttribute( 'data-title');
      var caption = element.getAttribute( 'data-caption');
      
      var img = new Image();
      img.onload = function() {

        sourceDimensions = { w: img.width, h: img.height }; // Save original dimensions for later.
        target = this;
        createViewer( title, caption );
        lockBody();
        bindEvents();
        loop();
      }

      img.src = imageSource;
    }

    function bindEvents() {

      container.addEventListener( 'mousemove', onMouseMove,   false );
      container.addEventListener( 'touchmove', onTouchMove,   false );
      window.addEventListener(    'resize',    setDimensions, false );
      window.addEventListener(    'keyup',     onKeyUp,       false );
      target.addEventListener(    'click',     removeViewer,  false );
    }

    function unbindEvents() {

      container.removeEventListener( 'mousemove', onMouseMove,   false );
      container.removeEventListener( 'touchmove', onTouchMove,   false);
      window.removeEventListener(    'resize',    setDimensions, false );
      window.removeEventListener(    'keyup',     onKeyUp,       false );
      target.removeEventListener(    'click',     removeViewer,  false )
    }
  
    function onMouseMove( event ) {

      mouse.xDest = event.clientX;
      mouse.yDest = event.clientY;
    }

    function onTouchMove( event ) {

      event.preventDefault(); // Needed to keep this event firing.
      mouse.xDest = event.touches[0].clientX;
      mouse.yDest = event.touches[0].clientY;
    }

    // Exit on excape key pressed;
    function onKeyUp( event ) {

      event.preventDefault();
      if ( event.keyCode === KEYCODE_ESC ) {
        removeViewer();
      } 
    }
  
    function positionTarget() {

      mouse.xCurr += ( mouse.xDest - mouse.xCurr ) * 0.05;
      mouse.yCurr += ( mouse.yDest - mouse.yCurr ) * 0.05;

      if ( horizontalOrientation === true ) {

        // HORIZONTAL SCANNING
        currentPosition += ( mouse.xCurr - currentPosition );
        if( mouse.xCurr !== lastPosition ) {
          var position = parseFloat( currentPosition / containerDimensions.w );
          position = overflowArea.x * position;
          target.style[ 'webkitTransform' ] = 'translate3d(' + position + 'px, 0px, 0px)';
          target.style[ 'MozTransform' ] = 'translate3d(' + position + 'px, 0px, 0px)';
          target.style[ 'msTransform' ] = 'translate3d(' + position + 'px, 0px, 0px)';
          lastPosition = mouse.xCurr;
        }
      } else if ( horizontalOrientation === false ) {

        // VERTICAL SCANNING
        currentPosition += ( mouse.yCurr - currentPosition );
        if( mouse.yCurr !== lastPosition ) {
          var position = parseFloat( currentPosition / containerDimensions.h );
          position = overflowArea.y * position;
          target.style[ 'webkitTransform' ] = 'translate3d( 0px, ' + position + 'px, 0px)';
          target.style[ 'MozTransform' ] = 'translate3d( 0px, ' + position + 'px, 0px)';
          target.style[ 'msTransform' ] = 'translate3d( 0px, ' + position + 'px, 0px)';
          lastPosition = mouse.yCurr;
        }
      }
    }

    function main( element ) {

      // Parse arguments

      if ( !element ) {
        throw 'You need to pass an element!';
      }

      startTracking( element );
    }

    return extend( main, {
        resize: setDimensions,
        start: start,
        stop: stop
    });

})();