# The per-device keyboard-layout helper (nomarchy-keyboard-layout).
# Extracted from hyprland.nix (#150) so it is built ONCE and shared: the
# Hyprland module puts it on PATH and drives it from the hotplug watcher,
# while the display-transition tool calls it (restore_keyboards) after a
# config reload. Pass the module's { pkgs, lib, config }.
{ pkgs, lib, config }:
let
  sync = lib.getExe config.nomarchy.package;

  # Candidate layouts offered by the new-keyboard picker: the session
  # layout(s) (nomarchy.keyboard.layout, comma-split for a multi-layout
  # session) plus the extra nomarchy.keyboard.layouts pool. The pool is
  # deliberately NOT merged into input.kb_layout — those candidates are for
  # *external* keyboards and get applied per-device by the watcher's apply().
  # Loading them onto the session keyboard is what let a global switch flip
  # the built-in board to the wrong layout.
  pickerLayouts = lib.unique (
    (lib.splitString "," config.nomarchy.keyboard.layout)
    ++ config.nomarchy.keyboard.layouts
  );
in
# Per-device keyboard helper shared by the hotplug watcher and the manual
# System › Keyboard menu.  The configured candidates are listed first, then
# every XKB layout known to the system, so the feature works on a default
# install instead of silently disappearing until home.nix is edited.
pkgs.writeShellScriptBin "nomarchy-keyboard-layout" ''
    set -u
    sync=${sync}

    layouts() {
      printf '%s\n' ${lib.concatMapStringsSep " " lib.escapeShellArg pickerLayouts}
      ${pkgs.gawk}/bin/awk '
        /^! layout/ { in_layouts=1; next }
        /^!/ && in_layouts { exit }
        in_layouts && NF { print $1 }
      ' ${pkgs.xkeyboard_config}/share/X11/xkb/rules/base.lst
    }
    saved_map() { "$sync" get settings.keyboard.devices 2>/dev/null || echo '{}'; }
    saved_for() { saved_map | jq -r --arg k "$1" '.[$k] // empty'; }
    apply_runtime() { hyprctl keyword "device[$1]:kb_layout" "$2" >/dev/null 2>&1; }

    case "''${1:-}" in
      layouts)
        layouts | ${pkgs.gawk}/bin/awk 'NF && !seen[$0]++' ;;
      devices)
        hyprctl devices -j 2>/dev/null \
          | jq -r '.keyboards[] | "\(.name)\t\(.active_keymap // \"unknown\")"' ;;
      saved)
        [ -n "''${2:-}" ] || exit 64
        saved_for "$2" ;;
      restore)
        [ -n "''${2:-}" ] || exit 64
        layout=$(saved_for "$2")
        [ -n "$layout" ] && apply_runtime "$2" "$layout" ;;
      apply)
        [ -n "''${2:-}" ] && [ -n "''${3:-}" ] || exit 64
        layouts | ${pkgs.gnugrep}/bin/grep -Fxq "$3" \
          || { notify-send "Keyboard" "Unknown XKB layout: $3"; exit 64; }
        if apply_runtime "$2" "$3"; then
          map=$(saved_map | jq -c --arg k "$2" --arg v "$3" '. + {($k): $v}') || exit 1
          if "$sync" --quiet set settings.keyboard.devices "$map" --no-switch; then
            notify-send "Keyboard" "$2 → $3"
          else
            notify-send "Keyboard" "$2 → $3 for this session, but the choice could not be saved."
            exit 1
          fi
        else
          notify-send "Keyboard" "Could not apply $3 to $2."
          exit 1
        fi ;;
      forget)
        [ -n "''${2:-}" ] || exit 64
        map=$(saved_map | jq -c --arg k "$2" 'del(.[$k])') || exit 1
        "$sync" --quiet set settings.keyboard.devices "$map" --no-switch || exit 1
        apply_runtime "$2" ${lib.escapeShellArg config.nomarchy.keyboard.layout} || true
        notify-send "Keyboard" "$2 now follows the session layout." ;;
      *)
        echo "usage: nomarchy-keyboard-layout [layouts|devices|saved <device>|restore <device>|apply <device> <layout>|forget <device>]" >&2
        exit 64 ;;
    esac
  ''