/**
 * SVGInject - Version 1.2.1
 * A tiny, intuitive, robust, caching solution for injecting SVG files inline into the DOM.
 *
 * https://github.com/iconfu/svg-inject
 *
 * Copyright (c) 2018 INCORS, the creators of iconfu.com
 * @license MIT License - https://github.com/iconfu/svg-inject/blob/master/LICENSE
 */

(function(window, document) {
  // constants for better minification
  var _CREATE_ELEMENT_ = 'createElement';
  var _GET_ELEMENTS_BY_TAG_NAME_ = 'getElementsByTagName';
  var _LENGTH_ = 'length';
  var _STYLE_ = 'style';
  var _TITLE_ = 'title';
  var _UNDEFINED_ = 'undefined';
  var _SET_ATTRIBUTE_ = 'setAttribute';
  var _GET_ATTRIBUTE_ = 'getAttribute';

  var NULL = null;

  // constants
  var __SVGINJECT = '__svgInject';
  var ID_SUFFIX = '--inject-';
  var ID_SUFFIX_REGEX = new RegExp(ID_SUFFIX + '\\d+', "g");
  var LOAD_FAIL = 'LOAD_FAIL';
  var SVG_NOT_SUPPORTED = 'SVG_NOT_SUPPORTED';
  var SVG_INVALID = 'SVG_INVALID';
  var ATTRIBUTE_EXCLUSION_NAMES = ['src', 'alt', 'onload', 'onerror'];
  var A_ELEMENT = document[_CREATE_ELEMENT_]('a');
  var IS_SVG_SUPPORTED = typeof SVGRect != _UNDEFINED_;
  var DEFAULT_OPTIONS = {
    useCache: true,
    copyAttributes: true,
    makeIdsUnique: true
  };
  // Map of IRI referenceable tag names to properties that can reference them. This is defined in
  // https://www.w3.org/TR/SVG11/linking.html#processingIRI
  var IRI_TAG_PROPERTIES_MAP = {
    clipPath: ['clip-path'],
    'color-profile': NULL,
    cursor: NULL,
    filter: NULL,
    linearGradient: ['fill', 'stroke'],
    marker: ['marker', 'marker-end', 'marker-mid', 'marker-start'],
    mask: NULL,
    pattern: ['fill', 'stroke'],
    radialGradient: ['fill', 'stroke']
  };
  var INJECTED = 1;
  var FAIL = 2;

  var uniqueIdCounter = 1;
  var xmlSerializer;
  var domParser;


  // creates an SVG document from an SVG string
  function svgStringToSvgDoc(svgStr) {
    domParser = domParser || new DOMParser();
    return domParser.parseFromString(svgStr, 'text/xml');
  }


  // searializes an SVG element to an SVG string
  function svgElemToSvgString(svgElement) {
    xmlSerializer = xmlSerializer || new XMLSerializer();
    return xmlSerializer.serializeToString(svgElement);
  }


  // Returns the absolute url for the specified url
  function getAbsoluteUrl(url) {
    A_ELEMENT.href = url;
    return A_ELEMENT.href;
  }


  // Load svg with an XHR request
  function loadSvg(url, callback, errorCallback) {
    if (url) {
      var req = new XMLHttpRequest();
      req.onreadystatechange = function() {
        if (req.readyState == 4) {
          // readyState is DONE
          var status = req.status;
          if (status == 200) {
            // request status is OK
            callback(req.responseXML, req.responseText.trim());
          } else if (status >= 400) {
            // request status is error (4xx or 5xx)
            errorCallback();
          } else if (status == 0) {
            // request status 0 can indicate a failed cross-domain call
            errorCallback();
          }
        }
      };
      req.open('GET', url, true);
      req.send();
    }
  }


  // Copy attributes from img element to svg element
  function copyAttributes(imgElem, svgElem) {
    var attribute;
    var attributeName;
    var attributeValue;
    var attributes = imgElem.attributes;
    for (var i = 0; i < attributes[_LENGTH_]; i++) {
      attribute = attributes[i];
      attributeName = attribute.name;
      // Only copy attributes not explicitly excluded from copying
      if (ATTRIBUTE_EXCLUSION_NAMES.indexOf(attributeName) == -1) {
        attributeValue = attribute.value;
        // If img attribute is "title", insert a title element into SVG element
        if (attributeName == _TITLE_) {
          var titleElem;
          var firstElementChild = svgElem.firstElementChild;
          if (firstElementChild && firstElementChild.localName.toLowerCase() == _TITLE_) {
            // If the SVG element's first child is a title element, keep it as the title element
            titleElem = firstElementChild;
          } else {
            // If the SVG element's first child element is not a title element, create a new title
            // ele,emt and set it as the first child
            titleElem = document[_CREATE_ELEMENT_ + 'NS']('http://www.w3.org/2000/svg', _TITLE_);
            svgElem.insertBefore(titleElem, firstElementChild);
          }
          // Set new title content
          titleElem.textContent = attributeValue;
        } else {
          // Set img attribute to svg element
          svgElem[_SET_ATTRIBUTE_](attributeName, attributeValue);
        }
      }
    }
  }


  // This function appends a suffix to IDs of referenced elements in the <defs> in order to  to avoid ID collision
  // between multiple injected SVGs. The suffix has the form "--inject-X", where X is a running number which is
  // incremented with each injection.  References to the ids are adjusted accordingly.
  // We assume tha all ids within the injected SVG are unique, therefore the same suffix can be used for all ids of one
  // injected SVG.
  function makeIdsUnique(svgElem) {
    var idSuffix = ID_SUFFIX + uniqueIdCounter++;
    // Get all elements with an id. The SVG spec recommends to put referenced elements inside <defs> elements, but
    // this is a requirement, therefore we have to search for IDs in the whole SVG.
    var idElements = svgElem.querySelectorAll('[id]');
    var idElem;
    var tagName;
    var iriTagNames = {};
    var iriProperties = [];
    var changed = false;
    var i, j;

    for (i = 0; i < idElements[_LENGTH_]; i++) {
      idElem = idElements[i];
      tagName = idElem.localName; // Use non-namespaced tag name
      // Make ID unique if tag name is IRI referenceable
      if (tagName in IRI_TAG_PROPERTIES_MAP) {
        changed = true;
        iriTagNames[tagName] = 1;
        // Add suffix to element's id
        idElem.id += idSuffix;
        // Replace ids in xlink:ref and href attributes
        ['xlink:href', 'href'].forEach(function(refAttrName) {
          var iri = idElem[_GET_ATTRIBUTE_](refAttrName);
          if (/^\s*#/.test(iri)) { // Check if iri is non-null and has correct format
            idElem[_SET_ATTRIBUTE_](refAttrName, iri.trim() + idSuffix);
          }
        });
      }
    }

    // Get all properties that are mapped to the found tags
    for (tagName in iriTagNames) {
      (IRI_TAG_PROPERTIES_MAP[tagName] || [tagName]).forEach(function (mappedProperty) {
        // Add mapped properties to array of iri referencing properties.
        // Use linear search here because the number of possible entries is very small (maximum 11)
        if (iriProperties.indexOf(mappedProperty) < 0) {
          iriProperties.push(mappedProperty);
        }
      });
    }

    // Replace IDs with new IDs in all references
    if (iriProperties[_LENGTH_]) {
      // Add "style" to properties, because it may contain references in the form 'style="fill:url(#myFill)"'
      iriProperties.push(_STYLE_);
      // Regular expression for functional notations of an IRI references. This will find occurences in the form
      // url(#anyId) or url("#anyId") (for Internet Explorer)
      var funcIriRegex = /url\("?#([a-zA-Z][\w:.-]*)"?\)/g;
      // Run through all elements of the SVG and replace ids in references. It seems that getElementsByTagName('*')
      // performs faster than querySelectorAll('*') in this case.
      var allElements = svgElem[_GET_ELEMENTS_BY_TAG_NAME_]('*');
      var element;
      var propertyName;
      var value;
      var newValue;
      for (i = 0; i < allElements[_LENGTH_]; i++) {
        element = allElements[i];
        if (element.localName == _STYLE_) {
          value = element.textContent;
          newValue = value && value.replace(funcIriRegex, 'url(#$1' + idSuffix + ')');
          if (newValue !== value) {
            element.textContent = newValue;
          }
        } else if (element.hasAttributes()) {
          // Run through all property names for which ids were found
          for (j = 0; j < iriProperties[_LENGTH_]; j++) {
            propertyName = iriProperties[j];
            value = element[_GET_ATTRIBUTE_](propertyName);
            newValue = value && value.replace(funcIriRegex, 'url(#$1' + idSuffix + ')');
            if (newValue !== value) {
              element[_SET_ATTRIBUTE_](propertyName, newValue);
            }
          }
        }
      }
    }

    // return boolean if SVG element has been changed
    return changed;
  }

  // For alredy cached SVGs ids are made unique by simply replacing the already inserted unique ids with a 
  // higher id counter. This is much more performant as a call to makeIdsUnique().
  function makeIdsUniqueCached(svgString) {
    return svgString.replace(ID_SUFFIX_REGEX, ID_SUFFIX + uniqueIdCounter++);
  }

  // Inject SVG by replacing the img element with the SVG element in the DOM
  function inject(imgElem, svgElem, absUrl, options) {
    if (svgElem) {
      svgElem[_SET_ATTRIBUTE_]('data-inject-url', absUrl);
      var parentNode = imgElem.parentNode;
      if (parentNode) {
        if (options.copyAttributes) {
          copyAttributes(imgElem, svgElem);
        }
        // Invoke beforeInject hook if set
        var beforeInject = options.beforeInject;
        var injectElem = (beforeInject && beforeInject(imgElem, svgElem)) || svgElem;
        // Replace img element with new element. This is the actual injection.
        parentNode.replaceChild(injectElem, imgElem);
        // Mark img element as injected
        imgElem[__SVGINJECT] = INJECTED;
        removeOnLoadAttribute(imgElem);
        // Invoke afterInject hook if set
        var afterInject = options.afterInject;
        if (afterInject) {
          afterInject(imgElem, injectElem);
        }
      }
    } else {
      svgInvalid(imgElem, options);
    }
  }


  // Merges any number of options objects into a new object
  function mergeOptions() {
    var mergedOptions = {};
    var args = arguments;
    // Iterate over all specified options objects and add all properties to the new options object
    for (var i = 0; i < args[_LENGTH_]; i++) {
      var argument = args[i];
        for (var key in argument) {
          if (argument.hasOwnProperty(key)) {
            mergedOptions[key] = argument[key];
          }
        }
      }
    return mergedOptions;
  }


  // Adds the specified CSS to the document's <head> element
  function addStyleToHead(css) {
    var head = document[_GET_ELEMENTS_BY_TAG_NAME_]('head')[0];
    if (head) {
      var style = document[_CREATE_ELEMENT_](_STYLE_);
      style.type = 'text/css';
      style.appendChild(document.createTextNode(css));
      head.appendChild(style);
    }
  }


  // Builds an SVG element from the specified SVG string
  function buildSvgElement(svgStr, verify) {
    if (verify) {
      var svgDoc;
      try {
        // Parse the SVG string with DOMParser
        svgDoc = svgStringToSvgDoc(svgStr);
      } catch(e) {
        return NULL;
      }
      if (svgDoc[_GET_ELEMENTS_BY_TAG_NAME_]('parsererror')[_LENGTH_]) {
        // DOMParser does not throw an exception, but instead puts parsererror tags in the document
        return NULL;
      }
      return svgDoc.documentElement;  
    } else {
      var div = document.createElement('div');
      div.innerHTML = svgStr;
      return div.firstElementChild;
    }
  }


  function removeOnLoadAttribute(imgElem) {
    // Remove the onload attribute. Should only be used to remove the unstyled image flash protection and
    // make the element visible, not for removing the event listener.
    imgElem.removeAttribute('onload');
  }

  function errorMessage(msg) {
    console.error('SVGInject: ' + msg);
  }


  function fail(imgElem, status, options) {
    imgElem[__SVGINJECT] = FAIL;
    if (options.onFail) {
      options.onFail(imgElem, status);
    } else {
      errorMessage(status);
    }
  }


  function svgInvalid(imgElem, options) {
    removeOnLoadAttribute(imgElem);
    fail(imgElem, SVG_INVALID, options);
  }


  function svgNotSupported(imgElem, options) {
    removeOnLoadAttribute(imgElem);
    fail(imgElem, SVG_NOT_SUPPORTED, options);
  }


  function loadFail(imgElem, options) {
    fail(imgElem, LOAD_FAIL, options);
  }


  function removeEventListeners(imgElem) {
    imgElem.onload = NULL;
    imgElem.onerror = NULL;
  }


  function imgNotSet(msg) {
    errorMessage('no img element');
  }


  function createSVGInject(globalName, options) {
    var defaultOptions = mergeOptions(DEFAULT_OPTIONS, options);
    var svgLoadCache = {};

    if (IS_SVG_SUPPORTED) {
      // If the browser supports SVG, add a small stylesheet that hides the <img> elements until
      // injection is finished. This avoids showing the unstyled SVGs before style is applied.
      addStyleToHead('img[onload^="' + globalName + '("]{visibility:hidden;}');
    }


    /**
     * SVGInject
     *
     * Injects the SVG specified in the `src` attribute of the specified `img` element or array of `img`
     * elements. Returns a Promise object which resolves if all passed in `img` elements have either been
     * injected or failed to inject (Only if a global Promise object is available like in all modern browsers
     * or through a polyfill).
     *
     * Options:
     * useCache: If set to `true` the SVG will be cached using the absolute URL. Default value is `true`.
     * copyAttributes: If set to `true` the attributes will be copied from `img` to `svg`. Dfault value
     *     is `true.
     * makeIdsUnique: If set to `true` the id of elements in the `<defs>` element that can be references by
     *     property values (for example 'clipPath') are made unique by appending "--inject-X", where X is a
     *     running number which increases with each injection. This is done to avoid duplicate ids in the DOM.
     * beforeLoad: Hook before SVG is loaded. The `img` element is passed as a parameter. If the hook returns
     *     a string it is used as the URL instead of the `img` element's `src` attribute.
     * afterLoad: Hook after SVG is loaded. The loaded `svg` element and `svg` string are passed as a
     *     parameters. If caching is active this hook will only get called once for injected SVGs with the
     *     same absolute path. Changes to the `svg` element in this hook will be applied to all injected SVGs
     *     with the same absolute path. It's also possible to return an `svg` string or `svg` element which
     *     will then be used for the injection.
     * beforeInject: Hook before SVG is injected. The `img` and `svg` elements are passed as parameters. If
     *     any html element is returned it gets injected instead of applying the default SVG injection.
     * afterInject: Hook after SVG is injected. The `img` and `svg` elements are passed as parameters.
     * onAllFinish: Hook after all `img` elements passed to an SVGInject() call have either been injected or
     *     failed to inject.
     * onFail: Hook after injection fails. The `img` element and a `status` string are passed as an parameter.
     *     The `status` can be either `'SVG_NOT_SUPPORTED'` (the browser does not support SVG),
     *     `'SVG_INVALID'` (the SVG is not in a valid format) or `'LOAD_FAILED'` (loading of the SVG failed).
     *
     * @param {HTMLImageElement} img - an img element or an array of img elements
     * @param {Object} [options] - optional parameter with [options](#options) for this injection.
     */
    function SVGInject(img, options) {
      options = mergeOptions(defaultOptions, options);

      var run = function(resolve) {
        var allFinish = function() {
          var onAllFinish = options.onAllFinish;
          if (onAllFinish) {
            onAllFinish();
          }          
          resolve && resolve();
        };

        if (img && typeof img[_LENGTH_] != _UNDEFINED_) {
          // an array like structure of img elements
          var injectIndex = 0;
          var injectCount = img[_LENGTH_];

          if (injectCount == 0) {
            allFinish();
          } else {
            var finish = function() {
              if (++injectIndex == injectCount) {
                allFinish();
              }
            };
            
            for (var i = 0; i < injectCount; i++) {
              SVGInjectElement(img[i], options, finish);
            }
          }
        } else {
          // only one img element
          SVGInjectElement(img, options, allFinish);
        }
      };

      // return a Promise object if it is globally available
      return typeof Promise == _UNDEFINED_ ? run() : new Promise(run);
    }


    // Injects a single svg element. Options must be already merged with the default options.
    function SVGInjectElement(imgElem, options, callback) {
      if (imgElem) {
        var svgInjectAttributeValue = imgElem[__SVGINJECT];
        if (!svgInjectAttributeValue) {
          removeEventListeners(imgElem);

          if (!IS_SVG_SUPPORTED) {
            svgNotSupported(imgElem, options);
            callback();
            return;
          }
          // Invoke beforeLoad hook if set. If the beforeLoad returns a value use it as the src for the load
          // URL path. Else use the imgElem src attribute value.
          var beforeLoad = options.beforeLoad;
          var src = (beforeLoad && beforeLoad(imgElem)) || imgElem[_GET_ATTRIBUTE_]('src');

          if (!src) {
            // If no image src attribute is set do no injection. This can only be reached by using javascript
            // because if no src attribute is set the onload and onerror events do not get called
            if (src === '') {
              loadFail(imgElem, options);
            }
            callback();
            return;
          }

          // set array so later calls can register callbacks
          var onFinishCallbacks = [];
          imgElem[__SVGINJECT] = onFinishCallbacks;

          var onFinish = function() {
            callback();
            onFinishCallbacks.forEach(function(onFinishCallback) {
              onFinishCallback();
            });
          };

          var absUrl = getAbsoluteUrl(src);
          var useCacheOption = options.useCache;
          var makeIdsUniqueOption = options.makeIdsUnique;

          var setSvgLoadCacheValue = function(val) {
            if (useCacheOption) {
              svgLoadCache[absUrl].forEach(function(svgLoad) {
                svgLoad(val);
              });
              svgLoadCache[absUrl] = val;
            }
          };

          if (useCacheOption) {
            var svgLoad = svgLoadCache[absUrl];

            var handleLoadValue = function(loadValue) {
              if (loadValue === LOAD_FAIL) {
                loadFail(imgElem, options);
              } else if (loadValue === SVG_INVALID) {
                svgInvalid(imgElem, options);
              } else {
                var hasUniqueIds = loadValue[0];
                var svgString = loadValue[1];
                var uniqueIdsSvgString = loadValue[2];
                var svgElem;
                
                if (makeIdsUniqueOption) {
                  if (hasUniqueIds === NULL) {
                    // Ids for the SVG string have not been made unique before. This may happen if previous
                    // injection of a cached SVG have been run with the option makedIdsUnique set to false
                    svgElem = buildSvgElement(svgString, false);
                    hasUniqueIds = makeIdsUnique(svgElem);

                    loadValue[0] = hasUniqueIds;
                    loadValue[2] = hasUniqueIds && svgElemToSvgString(svgElem);
                  } else if (hasUniqueIds) {
                    // Make ids unique for already cached SVGs with better performance
                    svgString = makeIdsUniqueCached(uniqueIdsSvgString);
                  }
                }

                svgElem = svgElem || buildSvgElement(svgString, false);
                    
                inject(imgElem, svgElem, absUrl, options);
              }
              onFinish();
            };

            if (typeof svgLoad != _UNDEFINED_) {
              // Value for url exists in cache
              if (svgLoad.isCallbackQueue) {
                // Same url has been cached, but value has not been loaded yet, so add to callbacks
                svgLoad.push(handleLoadValue);
              } else {
                handleLoadValue(svgLoad);
              }
              return;
            } else {
              // 
              var svgLoad = [];
              // set property isCallbackQueue to Array to differentiate from array with cached loaded values  
              svgLoad.isCallbackQueue = true;
              svgLoadCache[absUrl] = svgLoad;
            }
          }

          // Load the SVG because it is not cached or caching is disabled
          loadSvg(absUrl, function(svgXml, svgString) {
            // Use the XML from the XHR request if it is an instance of Document. Otherwise
            // (for example of IE9), create the svg document from the svg string.
            var svgElem = svgXml instanceof Document ? svgXml.documentElement : buildSvgElement(svgString, true);

            var afterLoad = options.afterLoad;
            if (afterLoad) {
              // Invoke afterLoad hook which may modify the SVG element. After load may also return a new
              // svg element or svg string
              var svgElemOrSvgString = afterLoad(svgElem, svgString) || svgElem;
              
              if (svgElemOrSvgString) {
                // Update svgElem and svgString because of modifications to the SVG element or SVG string in
                // the afterLoad hook, so the modified SVG is also used for all later cached injections
                var isString = typeof svgElemOrSvgString == 'string';
                svgString = isString ? svgElemOrSvgString : svgElemToSvgString(svgElem);
                svgElem = isString ? buildSvgElement(svgElemOrSvgString, true) : svgElemOrSvgString;
              }
            }

            if (svgElem instanceof SVGElement) {
              var hasUniqueIds = NULL;
              if (makeIdsUniqueOption) {
                hasUniqueIds = makeIdsUnique(svgElem);
              }

              if (useCacheOption) {
                var uniqueIdsSvgString = hasUniqueIds && svgElemToSvgString(svgElem);
                // set an array with three entries to the load cache
                setSvgLoadCacheValue([hasUniqueIds, svgString, uniqueIdsSvgString]);
              }

              inject(imgElem, svgElem, absUrl, options);
            } else {
              svgInvalid(imgElem, options);
              setSvgLoadCacheValue(SVG_INVALID);
            }
            onFinish();
          }, function() {
            loadFail(imgElem, options);
            setSvgLoadCacheValue(LOAD_FAIL);
            onFinish();
          });
        } else {
          if (Array.isArray(svgInjectAttributeValue)) {
            // svgInjectAttributeValue is an array. Injection is not complete so register callback
            svgInjectAttributeValue.push(callback);
          } else {
            callback();
          }
        }
      } else {
        imgNotSet();
      }
    }


    /**
     * Sets the default [options](#options) for SVGInject.
     *
     * @param {Object} [options] - default [options](#options) for an injection.
     */
    SVGInject.setOptions = function(options) {
      defaultOptions = mergeOptions(defaultOptions, options);
    };


    // Create a new instance of SVGInject
    SVGInject.create = createSVGInject;


    /**
     * Used in onerror Event of an `<img>` element to handle cases when the loading the original src fails
     * (for example if file is not found or if the browser does not support SVG). This triggers a call to the
     * options onFail hook if available. The optional second parameter will be set as the new src attribute
     * for the img element.
     *
     * @param {HTMLImageElement} img - an img element
     * @param {String} [fallbackSrc] - optional parameter fallback src
     */
    SVGInject.err = function(img, fallbackSrc) {
      if (img) {
        if (img[__SVGINJECT] != FAIL) {
          removeEventListeners(img);

          if (!IS_SVG_SUPPORTED) {
            svgNotSupported(img, defaultOptions);
          } else {
            removeOnLoadAttribute(img);
            loadFail(img, defaultOptions);
          }
          if (fallbackSrc) {
            removeOnLoadAttribute(img);
            img.src = fallbackSrc;
          }
        }
      } else {
        imgNotSet();
      }
    };

    window[globalName] = SVGInject;

    return SVGInject;
  }

  var SVGInjectInstance = createSVGInject('SVGInject');

  if (typeof module == 'object' && typeof module.exports == 'object') {
    module.exports = SVGInjectInstance;
  }
})(window, document);