{ config, pkgs, lib, ... }:

with lib;
let
  firefox-addons = pkgs.nur.repos.rycee.firefox-addons;

  prefer-dark-theme =
    config.gtk.gtk3.extraConfig.gtk-application-prefer-dark-theme;

  sharedSettings = {
    # Privacy recommendations from https://www.privacytools.io/browsers/#about_config
    "privacy.firstparty.isolate" = true;
    # "privacy.resistFingerprinting" = true; # forces ui.systemUsesDarkTheme to false
    "privacy.trackingprotection.fingerprinting.enabled" = true;
    "privacy.trackingprotection.cryptomining.enabled" = true;
    "privacy.trackingprotection.socialtracking.enabled" = true;
    "privacy.trackingprotection.enabled" = true;
    "browser.send_pings" = false;
    "browser.urlbar.speculativeConnect.enabled" = false;
    "dom.event.clipboardevents.enabled" = false;
    "media.eme.enabled" = false;
    "media.gmp-widevinecdm.enabled" = false;
    "media.navigator.enabled" = false;
    "network.cookie.cookieBehavior" = 1;
    "network.http.referer.XOriginPolicy" = 2;
    "network.http.referer.XOriginTrimmingPolicy" = 2;
    # "webgl.disabled" = true;
    "browser.sessionstore.privacy_level" = 2;
    "network.IDN_show_punycode" = true;

    # Theme
    "ui.systemUsesDarkTheme" = prefer-dark-theme;
    "extensions.activeThemeID" = concatStrings [
      "firefox-compact-"
      (if prefer-dark-theme then "dark" else "light")
      "@mozilla.org"
    ];
    "devtools.theme" = if prefer-dark-theme then "dark" else "light";

    # i18n
    "intl.accept_languages" = "en-GB, en";
    "intl.regional_prefs.use_os_locales" = true;

    # Other
    "browser.startup.page" = 3;
    "browser.ssb.enabled" = true;
    "browser.tabs.drawInTitlebar" = true;
    "browser.aboutConfig.showWarning" = false;
    "signon.rememberSignons" = false;
    "services.sync.engine.passwords" = false;
    "browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons" = false;
    "browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features" =
      false;
    "browser.newtabpage.activity-stream.feeds.snippets" = false;
  };
in {
  programs.firefox = {
    enable = true;
    package = pkgs.firefox.override { cfg = { enableFXCastBridge = true; }; };
    profiles = {
      private = {
        id = 0;
        settings = sharedSettings;
      };
      work = {
        id = 1;
        settings = sharedSettings;
      };
    };
    extensions = with firefox-addons; [
      https-everywhere
      ublock-origin
      decentraleyes
      clearurls
      terms-of-service-didnt-read
      vimium
      ipfs-companion
      bitwarden
      darkreader
      # not available yet:
      # languagetool
      # fx_cast
      # google-lighthouse
    ];
  };

  home.packages = let
    escapeDesktopArg = arg:
      replaceStrings [ ''"'' ] [ ''"\""'' ] (toString arg);
    makeFirefoxProfileDesktopItem = attrs:
      let
        mkExec = with lib;
          { name, profile, ... }: ''
            firefox -p "${escapeDesktopArg profile}" --class="firefox-${
              escapeDesktopArg name
            }"
          '';
      in pkgs.makeDesktopItem ((removeAttrs attrs [ "profile" ]) // {
        exec = mkExec attrs;
        extraEntries = ''
          StartupWMClass="${escapeDesktopArg attrs.name}"
        '';
      });
    makeFirefoxWebAppDesktopItem = attrs:
      let
        # --class not yet respected: https://bugzilla.mozilla.org/show_bug.cgi?id=1606247
        mkExec = with lib;
          { app, name, profile ? "private", ... }: ''
            firefox -p "${escapeDesktopArg profile}" --ssb="${
              escapeDesktopArg app
            }" --class="${escapeDesktopArg name}"
          '';
      in pkgs.makeDesktopItem ((removeAttrs attrs [ "app" "profile" ]) // {
        exec = mkExec attrs;
        extraEntries = ''
          StartupWMClass="${escapeDesktopArg attrs.name}"
        '';
      });
  in (with pkgs;
    [ (tor-browser-bundle-bin.override { pulseaudioSupport = true; }) ]) ++ [
      (makeFirefoxProfileDesktopItem {
        name = "firefox-work";
        desktopName = "Firefox (Work)";
        icon = "firefox"; # TODO looks different
        profile = "work";
      })
      (makeFirefoxWebAppDesktopItem {
        name = "element";
        desktopName = "Element";
        app = "https://app.element.io";
      })
      (makeFirefoxWebAppDesktopItem {
        name = "youtube-music";
        desktopName = "YouTube Music";
        app = "https://music.youtube.com";
      })
    ];
}