// ==UserScript==
// @name           Clear Downloads Panel Button
// @version        1.4.3
// @author         aminomancer
// @homepageURL    https://github.com/aminomancer/uc.css.js
// @description    Place a "Clear Downloads" button in the downloads panel, right next to the "Show all downloads" button.
// @downloadURL    https://cdn.jsdelivr.net/gh/aminomancer/uc.css.js@master/JS/clearDownloadsButton.uc.js
// @updateURL      https://cdn.jsdelivr.net/gh/aminomancer/uc.css.js@master/JS/clearDownloadsButton.uc.js
// @license        This Source Code Form is subject to the terms of the Creative Commons Attribution-NonCommercial-ShareAlike International License, v. 4.0. If a copy of the CC BY-NC-SA 4.0 was not distributed with this file, You can obtain one at http://creativecommons.org/licenses/by-nc-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
// ==/UserScript==

class ClearDLPanel {
  constructor() {
    this.makeButton();
    this.setCountHandler();
    Services.obs.addObserver(this, "downloads-panel-count-changed");
  }
  async genStrings() {
    this.strings = await new Localization(["browser/downloads.ftl"], true);
    const messages = await this.strings.formatMessages([
      "downloads-cmd-clear-downloads",
    ]);
    this.label = messages[0].attributes[0].value;
    this.accessKey = messages[0].attributes[1].value;
    return [this.label, this.accessKey];
  }
  async makeButton() {
    this.clearPanelButton = document.createXULElement("button");
    let strings = await this.genStrings();
    let labelString = this.sentenceCase(strings[0]);
    for (const [key, val] of Object.entries({
      id: "clearDownloadsPanel",
      class:
        DownloadsView.downloadsHistory.className ||
        "downloadsPanelFooterButton subviewbutton panel-subview-footer-button toolbarbutton-1",
      label: labelString,
      accesskey: strings[1],
      flex: "1",
      pack: "start",
    })) {
      this.clearPanelButton.setAttribute(key, val);
    }
    this.clearPanelButton.addEventListener("command", () => {
      goDoCommand("downloadsCmd_clearList");
      DownloadsPanel.hidePanel();
    });
    DownloadsView.downloadsHistory.after(this.clearPanelButton);
    this.clearPanelButton.hidden = !DownloadsView._visibleViewItems?.size > 0;
    this.clearPanelButton
      ?.closest("#downloadsFooter")
      .prepend(document.createXULElement("toolbarseparator"));
    this.clearPanelButton?.parentElement.setAttribute("uc-hbox", "true");
  }
  sentenceCase(str) {
    return str
      .toLocaleLowerCase()
      .replace(RTL_UI ? /.$/i : /^./i, function (letter) {
        return letter.toLocaleUpperCase();
      })
      .trim();
  }
  setCountHandler() {
    eval(
      `DownloadsView._itemCountChanged = function ${DownloadsView._itemCountChanged
        .toSource()
        .replace(
          /hiddenCount \> 0\;\n/,
          `hiddenCount > 0;\n    Services.obs.notifyObservers(null, "downloads-panel-count-changed", String(count));\n`
        )}`
    );
  }
  observe(_sub, _top, data) {
    this.clearPanelButton.hidden = parseInt(data) < 1;
  }
}

if (gBrowserInit.delayedStartupFinished) {
  new ClearDLPanel();
} else {
  let delayedListener = (subject, topic) => {
    if (topic == "browser-delayed-startup-finished" && subject == window) {
      Services.obs.removeObserver(delayedListener, topic);
      new ClearDLPanel();
    }
  };
  Services.obs.addObserver(delayedListener, "browser-delayed-startup-finished");
}