/*
 *  bgBrightness.js
 *
 *  Copyright 2016, Jesse Lee & Organic Themes w/ snippets from ColourBrightness.js
 *  Released under the WTFPL license
 *  https://organicthemes.com
 *
 *  Version: 1.0
 */
( function( $ ) {

"use strict";

	$.fn.bgBrightness = function(contentSelectors, threshold = 160){

		// Background Object
		var $el = this;

		// Content Targets
		if ( ! contentSelectors ) {
			contentSelectors = false;
		} else if ( !( contentSelectors.constructor === Array) ) {
			contentSelectors = [contentSelectors];
		}

    //Loop Through all Items
		$el.each( function(key, value){

      //Initialize
      var r,g,b,brightness;

      //Get Background Styles for element
      var bgStyles = getBackgroundStyles( $(value) );
      var colour = bgStyles.bgColor;
      var image = bgStyles.bgImage;
      var targetedElement = bgStyles.targetedElement;

      // If bg image found, calculate luminosity of image
      if ( image ) {
        getBackgroundImageLuminosity( targetedElement, contentSelectors, threshold);
      }
      // If no bg image, calculate bg color brightness
      else if ( colour ) {
        if (colour.match(/^rgb/)) {
          colour = colour.match(/rgba?\(([^)]+)\)/)[1];
          colour = colour.split(/ *, */).map(Number);
          r = colour[0];
          g = colour[1];
          b = colour[2];
        } else if ('#' == colour[0] && 7 == colour.length) {
          r = parseInt(colour.slice(1, 3), 16);
          g = parseInt(colour.slice(3, 5), 16);
          b = parseInt(colour.slice(5, 7), 16);
        } else if ('#' == colour[0] && 4 == colour.length) {
          r = parseInt(colour[1] + colour[1], 16);
          g = parseInt(colour[2] + colour[2], 16);
          b = parseInt(colour[3] + colour[3], 16);
        }

        brightness = (r * 299 + g * 587 + b * 114) / 1000;

        if (brightness < threshold) {
          // white text
          targetedElement.removeClass("block-lite-bg-light").addClass("block-lite-bg-dark");
        } else {
          // black text
          targetedElement.removeClass("block-lite-bg-dark").addClass("block-lite-bg-light");
        }

      }

		});

		function getBackgroundImageLuminosity($el, contentSelectors, threshold ) {

			var bg = $el.css('background-image');
			bg = bg.replace(/^url\(['"]?/,'').replace(/['"]?\)$/,'');

			getImageLightness( bg, $el ,function(brightness,$el){

        // Set classes to add and to remove
        if (brightness < threshold) {
          var addClass = 'block-lite-bg-dark';
          var removeClass = 'block-lite-bg-light';
        } else {
          var addClass = 'block-lite-bg-light';
          var removeClass = 'block-lite-bg-dark';
        }

        // Add and remove classes
        // If applying to self
        if (!contentSelectors ){
          if ( !$el.hasClass('block-lite-bg-img') ) $el.addClass('block-lite-bg-img');
          $el.removeClass(removeClass);
          $el.addClass(addClass);
        }
        // If applying to custom selectors
        else {
          contentSelectors.forEach(function(contentSelector){
            if ( !$(contentSelector).hasClass('block-lite-bg-img') ) $(contentSelector).addClass('block-lite-bg-img');
            $(contentSelector).removeClass(removeClass);
            $(contentSelector).addClass(addClass);
          });
        }

				}); // End getImageLightness(){}

		} // End getBackgroundImageLuminosity(){}

		function getImageLightness(imageSrc, imgObject, callback) {
			var img = document.createElement("img");
			img.crossBlock = "Anonymous";
			img.src = imageSrc;
			img.style.display = "none";
			document.body.appendChild(img);

			var colorSum = 0;

			img.onload = function() {
				// create canvas
				var canvas = document.createElement( "canvas" );
				canvas.width = this.width;
				canvas.height = this.height;

				var ctx = canvas.getContext( "2d" );
				ctx.drawImage(this,0,0);

				var imageData = ctx.getImageData( 0, 0, canvas.width, canvas.height );
				var data = imageData.data;
				var r,g,b,avg;

				for( var x = 0, len = data.length; x < len; x += 4 ) {
					r = data[x];
					g = data[x + 1];
					b = data[x + 2];

					avg = Math.floor( (r + g + b) / 3 );
					colorSum += avg;
				}

				var brightness = Math.floor(colorSum / (this.width * this.height));
				callback(brightness, imgObject);
			}
		} // End getImageLightness(){}



    /* ======== ColourBrightness Addons =========*/

    function getBackgroundStyles($el) {
      var bgColor = false;
      var bgImage = false;
      while($el[0].tagName.toLowerCase() != "html") {
        bgColor =  ( ! $el.css("background-color") || $el.css("background-color") == "rgba(0, 0, 0, 0)" || $el.css("background-color") == "transparent" ) ? false : $el.css("background-color");
        bgImage = ( ! $el.css("background-image") || $el.css("background-image") == "" || $el.css("background-image") == "none" ) ? false : $el.css("background-image");
        if( bgColor || bgImage ) {
          break;
        }
        $el = $el.parent();
      }
      return { bgColor: bgColor, bgImage: bgImage, targetedElement: $el };
    }

	} // End bgBrightness(){}

})( jQuery );