{
  config,
  pkgs,
  ...
}:
let
  palette = import ./palette.nix;
  evdevPython = pkgs.python3.withPackages (ps: [ ps.evdev ]);

  # Text-capable window classes. wvkbd's own --auto relies on Hyprland's
  # input-method-v2 protocol, which Hyprland advertises but never actually
  # fires — so auto show/hide is driven here by watching activewindow events.
  # Add classes (lowercase prefixes are allowed) for anything you type into.
  textApps = [
    "kitty"
    "alacritty"
    "wezterm"
    "konsole"
    "com.mitchellh.ghostty"
    "ghostty"
    "xterm"
    "firefox"
    "librewolf"
    "chromium"
    "chromium-browser"
    "google-chrome"
    "microsoft-edge"
    "brave-browser"
    "thunderbird"
    "com.github.xournalpp.xournalpp"
    "code"
    "code-url-handler"
    "zen"
  ];

  # Shell-escaped arg list for the CLI fallback (same content as wvkbdFlags
  # but space-joined for shell expansion). The daemon receives the JSON form.
  # The font spec is double-quoted so it survives shell word-splitting.
  wvkbdFlagsShell = pkgs.lib.concatStringsSep " " [
    "-l"
    "simple"
    "-H"
    "300"
    "-L"
    "200"
    "--fn"
    "\"DejaVu Sans 24\""
    "--alpha"
    "235"
    "--bg"
    "${palette.wvkbdBg}"
    "--fg"
    "${palette.surface}"
    "--fg-sp"
    "${palette.wvkbdFgSp}"
    "--press"
    "${palette.neon}"
    "--press-sp"
    "${palette.violet}"
    "--text"
    "${palette.text}"
    "--text-sp"
    "${palette.muted}"
    "--text-press"
    "${palette.ink}"
    "--text-press-sp"
    "${palette.ink}"
    "--swipe"
    "${palette.cyan}"
    "--swipe-sp"
    "${palette.violet}"
    "--text-swipe"
    "${palette.ink}"
    "--text-swipe-sp"
    "${palette.ink}"
  ];

  # wvkbd argv as a JSON array. The daemon splices this into place as a bare
  # Python expression — a JSON array of strings IS valid Python (list of
  # double-quoted strings), so no quote-escaping headaches at build time.
  wvkbdArgs = [
    "-l"
    "simple"
    "-H"
    "300"
    "-L"
    "200"
    "--fn"
    "DejaVu Sans 24"
    "--alpha"
    "235"
    "--bg"
    "${palette.wvkbdBg}"
    "--fg"
    "${palette.surface}"
    "--fg-sp"
    "${palette.wvkbdFgSp}"
    "--press"
    "${palette.neon}"
    "--press-sp"
    "${palette.violet}"
    "--text"
    "${palette.text}"
    "--text-sp"
    "${palette.muted}"
    "--text-press"
    "${palette.ink}"
    "--text-press-sp"
    "${palette.ink}"
    "--swipe"
    "${palette.cyan}"
    "--swipe-sp"
    "${palette.violet}"
    "--text-swipe"
    "${palette.ink}"
    "--text-swipe-sp"
    "${palette.ink}"
  ];
  wvkbdArgsJson = builtins.toJSON wvkbdArgs;

  # Text-app allowlist as a JSON array, spliced the same way (valid Python
  # list literal after substitution).
  textAppsJson = builtins.toJSON textApps;

  # Place build-time paths into the daemon (replaceVars honours the
  # @VAR@ placeholders) and run it with the evdev-enabled python.
  daemon = pkgs.replaceVarsWith {
    name = "hyprland-tablet-daemon";
    src = pkgs.writeScript "hyprland-tablet-daemon-src" ''
      #!${evdevPython}/bin/python3
      ${builtins.readFile ./hyprland-tablet-daemon.py}
    '';
    isExecutable = true;
    replacements = {
      EVDEV_DEVICE = "/dev/input/event17";
      WVKBD_PATH = "${pkgs.wvkbd}/bin/wvkbd-mobintl";
      WVKBD_ARGS = wvkbdArgsJson;
      TEXT_APPS_JSON = textAppsJson;
      MONITOR_SENSOR = "${pkgs.iio-sensor-proxy}/bin/monitor-sensor";
      HYPRCTL = "${pkgs.hyprland}/bin/hyprctl";
    };
  };

  # Toggle/show/hide are forwarded to the daemon over a Unix datagram socket
  # so manual control and focus-driven auto-hide share one visibility state.
  cli = pkgs.writeShellScriptBin "hyprland-tablet" ''
        set -eu
        state_file="$XDG_RUNTIME_DIR/hyprland-tablet"
        ctl_sock="$XDG_RUNTIME_DIR/hyprland-tablet.ctl"

        ctl_send() {
          if [ -S "$ctl_sock" ]; then
            ${pkgs.python3}/bin/python3 -c '
    import os, socket, sys
    path = os.environ.get("XDG_RUNTIME_DIR", "/tmp") + "/hyprland-tablet.ctl"
    s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
    s.sendto(sys.argv[1].encode(), path)
    ' "$1"
            return 0
          fi
          return 1
        }

        osk_pid() {
          pgrep -f 'wvkbd-mobintl' | head -n1 || true
        }

        case "''${1:-}" in
          status)
            if [ -f "$state_file" ]; then
              cat "$state_file"
            else
              echo '{"tablet":false,"osk":false}'
            fi
            ;;
          # Toggle on-screen keyboard visibility. Manual control wins over the
          # daemon's focus-derived state until the next activewindow change.
          keyboard-toggle|osk-toggle)
            ctl_send toggle || {
              pid="$(osk_pid)"
              if [ -z "$pid" ]; then
                nohup ${pkgs.wvkbd}/bin/wvkbd-mobintl ${wvkbdFlagsShell} >/dev/null 2>&1 &
              else
                kill -SIGRTMIN "$pid"
              fi
            }
            ;;
          osk-show)
            ctl_send show || { pid="$(osk_pid)"; [ -n "$pid" ] && kill -SIGUSR2 "$pid"; }
            ;;
          osk-hide)
            ctl_send hide || { pid="$(osk_pid)"; [ -n "$pid" ] && kill -SIGUSR1 "$pid"; }
            ;;
          *)
            echo "usage: hyprland-tablet {status|keyboard-toggle|osk-show|osk-hide}" >&2
            exit 2
            ;;
        esac
  '';
in
{
  home.packages = [ cli ];

  systemd.user.services.hyprland-tablet = {
    Unit = {
      Description = "Hyprland tablet-mode auto-rotation + on-screen keyboard";
      After = [ "graphical-session.target" ];
      PartOf = [ "graphical-session.target" ];
    };
    Service = {
      Type = "simple";
      ExecStart = daemon;
      Restart = "on-failure";
    };
    Install = {
      WantedBy = [ "graphical-session.target" ];
    };
  };
}