"use strict";
const whatwgURL = require("whatwg-url");
const { notImplemented } = require("../../browser/not-implemented.js");
const reportException = require("../helpers/runtime-script-errors.js");
const { utf8Decode } = require("../helpers/encoding.js");
const idlUtils = require("../../../generated/idl/utils.js");

// https://html.spec.whatwg.org/#evaluate-a-javascript:-url, kind of
exports.evaluateJavaScriptURL = (window, urlRecord) => {
  const urlString = whatwgURL.serializeURL(urlRecord);
  const encodedScriptSource = urlString.substring("javascript:".length);
  const scriptSource = utf8Decode(whatwgURL.percentDecodeString(encodedScriptSource));
  if (window._runScripts === "dangerously") {
    try {
      return window.eval(scriptSource);
    } catch (e) {
      reportException(window, e, urlString);
    }
  }
  return undefined;
};

// https://html.spec.whatwg.org/#navigating-across-documents
exports.navigate = (window, newURL, flags) => {
  // This is NOT a spec-compliant implementation of navigation in any way. It implements a few selective steps that
  // are nice for jsdom users, regarding hash changes and JavaScript URLs. Full navigation support is being worked on
  // and will likely require some additional hooks to be implemented.
  if (!window._document) {
    return;
  }

  const document = idlUtils.implForWrapper(window._document);
  const currentURL = document._URL;

  if (!flags.reloadTriggered && urlEquals(currentURL, newURL, { excludeFragments: true })) {
    if (newURL.fragment !== currentURL.fragment) {
      navigateToFragment(window, newURL, flags);
    }
    return;
  }

  // NOT IMPLEMENTED: Prompt to unload the active document of browsingContext.

  // NOT IMPLEMENTED: form submission algorithm
  // const navigationType = 'other';

  // NOT IMPLEMENTED: if resource is a response...
  if (newURL.scheme === "javascript") {
    setTimeout(() => {
      const result = exports.evaluateJavaScriptURL(window, newURL);
      if (typeof result === "string") {
        notImplemented(window, "string results from 'javascript:' URLs");
      }
    }, 0);
    return;
  }
  navigateFetch(window);
};

// https://html.spec.whatwg.org/#scroll-to-fragid
function navigateToFragment(window, newURL, flags) {
  const document = idlUtils.implForWrapper(window._document);

  window._sessionHistory.clearHistoryTraversalTasks();

  if (!flags.replacement) {
    // handling replacement=true here deviates from spec, but matches real browser behaviour
    // see https://github.com/whatwg/html/issues/2796 for spec bug
    window._sessionHistory.removeAllEntriesAfterCurrentEntry();
  }
  const newEntry = { document, url: newURL };
  window._sessionHistory.addEntryAfterCurrentEntry(newEntry);
  window._sessionHistory.traverseHistory(newEntry, { nonBlockingEvents: true, replacement: flags.replacement });
}

// https://html.spec.whatwg.org/#process-a-navigate-fetch
function navigateFetch(window) {
  // TODO:
  notImplemented(window, "navigation to another Document");
}

// https://url.spec.whatwg.org/#concept-url-equals
function urlEquals(a, b, flags) {
  const serializedA = whatwgURL.serializeURL(a, flags.excludeFragments);
  const serializedB = whatwgURL.serializeURL(b, flags.excludeFragments);
  return serializedA === serializedB;
}
