{ pkgs, lib, ... }:
{
  name = "gnome-extensions";
  meta.maintainers = [ ];

  node.pkgsReadOnly = false;

  nodes.machine =
    { pkgs, ... }:
    {
      imports = [ ./common/user-account.nix ];

      # Install all extensions
      environment.systemPackages = lib.filter (e: e ? extensionUuid) (
        lib.attrValues pkgs.gnomeExtensions
      );

      # Some extensions are broken, but that's kind of the point of a testing VM
      nixpkgs.config.allowBroken = true;
      # There are some aliases which throw exceptions; ignore them.
      # Also prevent duplicate extensions under different names.
      nixpkgs.config.allowAliases = false;

      # Configure GDM
      services.xserver.enable = true;
      services.displayManager.gdm = {
        enable = true;
        debug = true;
      };
      services.displayManager.autoLogin = {
        enable = true;
        user = "alice";
      };

      # Configure Gnome
      services.desktopManager.gnome.enable = true;
      services.desktopManager.gnome.debug = true;

      systemd.user.services = {
        "org.gnome.Shell@" = {
          serviceConfig = {
            ExecStart = [
              # Clear the list before overriding it.
              ""
              # Eval API is now internal so Shell needs to run in unsafe mode.
              # TODO: improve test driver so that it supports openqa-like manipulation
              # that would allow us to drop this mess.
              "${pkgs.gnome-shell}/bin/gnome-shell --unsafe-mode"
            ];
          };
        };
      };

    };

  testScript =
    { nodes, ... }:
    let
      # Keep line widths somewhat manageable
      user = nodes.machine.users.users.alice;
      uid = toString user.uid;
      bus = "DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/${uid}/bus";
      # Run a command in the appropriate user environment
      run = command: "su - ${user.name} -c '${bus} ${command}'";

      # Call javascript in gnome shell, returns a tuple (success, output), where
      # `success` is true if the dbus call was successful and output is what the
      # javascript evaluates to.
      eval =
        command:
        run "gdbus call --session -d org.gnome.Shell -o /org/gnome/Shell -m org.gnome.Shell.Eval ${command}";

      # False when startup is done
      startingUp = eval "Main.layoutManager._startingUp";

      # Extensions to keep always enabled together
      # Those are extensions that are usually always on for many users, and that we expect to work
      # well together with most others without conflicts
      alwaysOnExtensions = map (name: pkgs.gnomeExtensions.${name}.extensionUuid) [
        "applications-menu"
        "user-themes"
      ];

      # Extensions to enable and disable individually
      # Extensions like dash-to-dock and dash-to-panel cannot be enabled at the same time.
      testExtensions = map (name: pkgs.gnomeExtensions.${name}.extensionUuid) [
        "appindicator"
        "dash-to-dock"
        "dash-to-panel"
        "ddterm"
        "gsconnect"
        "system-monitor-next"
        "desktop-icons-ng-ding"
        "workspace-indicator"
        "vitals"
      ];
    in
    ''
      with subtest("Login to GNOME with GDM"):
          # wait for gdm to start
          machine.wait_for_unit("display-manager.service")
          # wait for the wayland server
          machine.wait_for_file("/run/user/${uid}/wayland-0")
          # wait for alice to be logged in
          machine.wait_for_unit("default.target", "${user.name}")
          # check that logging in has given the user ownership of devices
          # Change back to /dev/snd/timer after systemd-258.1
          assert "alice" in machine.succeed("getfacl -p /dev/dri/card0")

      with subtest("Wait for GNOME Shell"):
          # correct output should be (true, 'false')
          machine.wait_until_succeeds(
              "${startingUp} | grep -q 'true,..false'"
          )

          # Close the Activities view so that Shell can correctly track the focused window.
          machine.send_key("esc")
          # # Disable extension version validation (only use for manual testing)
          # machine.succeed(
          #   "${run "gsettings set org.gnome.shell disable-extension-version-validation true"}"
          # )

      def getState(extension):
          return machine.succeed(
              f"${run "gnome-extensions info {extension}"} | grep '^  State: .*$'"
          )

      # Assert that some extension is in a specific state
      def checkState(target, extension):
          state = getState(extension)
          assert target in state, f"{state} instead of {target}"

      def checkExtension(extension, disable):
          with subtest(f"Enable extension '{extension}'"):
              # Check that the extension is properly initialized; skip out of date ones
              state = machine.succeed(
                  f"${run "gnome-extensions info {extension}"} | grep '^  State: .*$'"
              )
              if "OUT OF DATE" in state:
                  machine.log(f"Extension {extension} will be skipped because out of date")
                  return

              assert "INITIALIZED" in state, f"{state} instead of INITIALIZED"

              # Enable and optionally disable

              machine.succeed(f"${run "gnome-extensions enable {extension}"}")
              wait_time = 5
              while getState(extension) == "ACTIVATING" and (wait_time := wait_time - 1) > 0:
                  machine.log(f"Extension {extension} is still activating, waiting {wait_time} more seconds")
                  machine.sleep(1)
              checkState("ACTIVE", extension)

              if disable:
                  machine.succeed(f"${run "gnome-extensions disable {extension}"}")
                  checkState("INACTIVE", extension)
    ''
    + lib.concatLines (map (e: ''checkExtension("${e}", False)'') alwaysOnExtensions)
    + lib.concatLines (map (e: ''checkExtension("${e}", True)'') testExtensions);
}
