/**
 * Copyright 2019 Adobe. All rights reserved.
 * This file is licensed to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy
 * of the License at http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
 * OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

import {SPECTRUM_ICONS_COLOR} from './iconCollection';

function handleError(string) {
  string = `Coral.Icon#load: ${string}`;
  const error = new Error(string);

  console.error(error.toString());
}

function injectSVG(svgURL) {
  // 200 for web servers, 0 for CEP panels
  if (this.status !== 200 && this.status !== 0) {
    handleError(`failed to fetch icons, server returned ${this.status}`);
    return;
  }

  // Parse the SVG
  const parser = new DOMParser();
  try {
    const doc = parser.parseFromString(this.responseText, 'image/svg+xml');
    const svg = doc.firstChild;

    // Make sure a real SVG was returned
    if (svg && svg.tagName === 'svg') {
      if (svgURL.indexOf(SPECTRUM_ICONS_COLOR) !== -1) {
        // Insert it into the body
        if (document.body) {
          document.body.appendChild(svg);
        } else {
          document.addEventListener('DOMContentLoaded', () => {
            document.body.appendChild(svg);
          });
        }
      } else {
        document.head.appendChild(svg);
      }
    } else {
      handleError('parsed SVG document contained something other than an SVG');
    }
  } catch (err) {
    handleError(`error parsing SVG: ${err}`);
  }
}

function loadIcons(svgURL) {
  if (svgURL.slice(-3) === '.js') {
    // Injects the SVG icons in the document
    const script = document.createElement('script');
    script.async = true;
    script.type = 'text/javascript';
    script.src = svgURL;
    document.head.appendChild(script);
  } else {
    // Request the SVG icons
    const req = new XMLHttpRequest();
    req.open('GET', svgURL, true);
    req.addEventListener('load', injectSVG.bind(req, svgURL));
    req.addEventListener('error', () => {
      handleError('Request failed');
    });
    req.send();
  }
}

export default loadIcons;
