/*****************************************************************
** Author: Roland Schmehl, r.schmehl@tudelft.nl
**
** A plugin for displaying attribution texts sideways along the right
** edge of the viewport. When resizing the viewport or toggling full
** screen mode, the attribution text sticks persistently to the right
** edge of the viewport.
**
** The dynamic scaling of the attribution text via CSS transform
** is adopted from the fullscreen plugin.
**
** Version: 1.0
**
** License: MIT license (see file LICENSE)
**
******************************************************************/

window.RevealAttribution = window.RevealAttribution || {
    id: 'RevealAttribution',
    init: function(deck) {
        initAttribution(deck);
    }
};

const initAttribution = function(Reveal){

  var ready = false;
  var resize = false;
  var scale = 1;

  window.addEventListener( 'ready', function( event ) {

    var content;

    // Remove configured margin of the presentation
    var attribution = document.getElementsByClassName("attribution");
    var width = window.innerWidth;
    var configuredWidth = Reveal.getConfig().width;
    var configuredHeight = Reveal.getConfig().height;

    scale = 1/(1-Reveal.getConfig().margin);

    for (var i = 0; i < attribution.length; i++) {
      content = attribution[i].innerHTML;
      attribution[i].style.width = configuredWidth + "px";
      attribution[i].style.height = configuredHeight + "px";
      attribution[i].innerHTML = "<span class='content'>" + content + "</span>";
      attribution[i].style.transform = 'translate( -50%, -50% ) scale( ' + scale*100 + '% ) rotate(-180deg)';
    }

    // Scale with cover class to mimic backgroundSize cover
    resizeCover();

  });

  window.addEventListener( 'resize', resizeCover );

  function resizeCover() {

    // Scale to mimic backgroundSize cover
    var attribution = document.getElementsByClassName("attribution");
    var xScale = window.innerWidth / Reveal.getConfig().width;
    var yScale = window.innerHeight / Reveal.getConfig().height;
    var s = 1;

    if (xScale > yScale) {
        // The div fits perfectly in x axis, stretched in y
        s = xScale/yScale;
    }
    for (var i = 0; i < attribution.length; i++) {
      attribution[i].style.transform = 'translate( -50%, -50% ) scale( ' + s*scale*100 + '% ) rotate(-180deg)';
    }
  }

};