function buildArgsHash(args) {
    let argsHash = {};
    args.forEach(arg => {
        const params = arg.split(':');
        argsHash[params[0]] = params[1];
    });

    return argsHash;
}

function generateWikipediaTagHtml(args, content) {
    const argsHash = buildArgsHash(args);
    const title = argsHash['title'];

    const lang = argsHash['lang'] !== undefined ? argsHash['lang'] : 'en';
    const baseUrl = `https://${lang}.wikipedia.org`;

    const url = `${baseUrl}/api/rest_v1/page/summary/${title}?redirect=false`;

    const tagId = Math.round(Math.random() * 100000);
    const embeddedScript = `
      window.addEventListener('load', function() {
        var element = document.getElementById('${tagId}');
        var req = new XMLHttpRequest();
        req.addEventListener("load", function() {
          var result = this.response;
          const extract = result.extract;
          element.prepend(extract);
        });
        req.addEventListener("error", function() {
          element.prepend('Failed to fetch wikipedia data for "${title}".');
        });
        req.open('GET', '${url}');
        req.responseType = 'json';
        req.setRequestHeader('accept', 'application/json; charset=utf-8; profile="https://www.mediawiki.org/wiki/Specs/Summary/1.4.2"');
        req.send();
      });
    `;
    let contentText = `<script>${embeddedScript}</script>`;
    if (argsHash['wikiButton'] === 'true') {
        contentText += `<p><a href="${baseUrl}/wiki/${title}">Wikipedia:${title}</a></p>`;
    }

    return `<blockquote id='${tagId}'>${contentText}</blockquote>`;
}

hexo.extend.tag.register('wikipedia', generateWikipediaTagHtml);