“use strict”; const internalQuerySelector = require(“./selectors”).querySelector; const whatwgURL = require(“whatwg-url”);

exports.documentBaseURL = document => {

// https://html.spec.whatwg.org/multipage/infrastructure.html#document-base-url

const firstBase = internalQuerySelector(document, "base[href]");
const fallbackBaseURL = exports.fallbackBaseURL(document);

if (firstBase === null) {
  return fallbackBaseURL;
}

return frozenBaseURL(firstBase, fallbackBaseURL);

};

exports.documentBaseURLSerialized = document => {

return whatwgURL.serializeURL(exports.documentBaseURL(document));

};

exports.fallbackBaseURL = document => {

// https://html.spec.whatwg.org/multipage/infrastructure.html#fallback-base-url

// Unimplemented: <iframe srcdoc>

if (document.URL === "about:blank" && document._defaultView &&
    document._defaultView._parent !== document._defaultView) {
  return exports.documentBaseURL(document._defaultView._parent._document);
}

return document._URL;

};

exports.parseURLToResultingURLRecord = (url, document) => {

// https://html.spec.whatwg.org/#resolve-a-url

// Encoding stuff ignored; always UTF-8 for us, for now.

const baseURL = exports.documentBaseURL(document);

return whatwgURL.parseURL(url, { baseURL });
// This returns the resulting URL record; to get the resulting URL string, just serialize it.

};

function frozenBaseURL(baseElement, fallbackBaseURL) {

// https://html.spec.whatwg.org/multipage/semantics.html#frozen-base-url
// The spec is eager (setting the frozen base URL when things change); we are lazy (getting it when we need to)

const baseHrefAttribute = baseElement.getAttribute("href");
const result = whatwgURL.parseURL(baseHrefAttribute, { baseURL: fallbackBaseURL });
return result === "failure" ? fallbackBaseURL : result;

}