wallpaper engine

modules/applications/linux-wallpaperengine/home/controller.sh

@@ -0,0 +1,167 @@
+# shellcheck shell=bash
+
+set -o errexit -o nounset -o pipefail
+
+playlist_file="$1"
+default_id="$2"
+configuration_id="$3"
+shift 3
+
+state_dir="${XDG_RUNTIME_DIR:?}/linux-wallpaperengine"
+state_file="$state_dir/current"
+
+usage() {
+  printf '%s\n' \
+    'Usage: wallpaperengine-wallpaper COMMAND [ID]' \
+    '' \
+    'Commands:' \
+    '  select ID Select a declaratively configured ID for this session' \
+    '  next      Select the next configured ID' \
+    '  previous  Select the previous configured ID' \
+    '  list      List configured IDs and mark the selected one' \
+    '  current   Print the selected ID' \
+    '  restart   Restart the selected wallpaper' \
+    '  stop      Stop Wallpaper Engine for this session'
+}
+
+load_playlist() {
+  mapfile -t wallpaper_ids < <(awk '/^[0-9]+$/ && !seen[$0]++' "$playlist_file")
+  if [ "${#wallpaper_ids[@]}" -eq 0 ]; then
+    echo "wallpaperengine-wallpaper: no wallpaper IDs are configured in settings.nix" >&2
+    exit 1
+  fi
+}
+
+contains_id() {
+  local candidate="$1"
+  local id
+
+  for id in "${wallpaper_ids[@]}"; do
+    [ "$id" = "$candidate" ] && return 0
+  done
+  return 1
+}
+
+current_id() {
+  local saved_configuration=""
+  local saved_id=""
+  local -a saved_state=()
+
+  if [ -s "$state_file" ]; then
+    mapfile -t saved_state <"$state_file"
+    saved_configuration="${saved_state[0]:-}"
+    saved_id="${saved_state[1]:-}"
+  fi
+
+  if [ "$saved_configuration" = "$configuration_id" ] && contains_id "$saved_id"; then
+    printf '%s\n' "$saved_id"
+  else
+    printf '%s\n' "$default_id"
+  fi
+}
+
+select_id() {
+  local id="$1"
+
+  if ! contains_id "$id"; then
+    echo "wallpaperengine-wallpaper: ID is not declared in settings.nix: $id" >&2
+    exit 2
+  fi
+
+  mkdir -p "$state_dir"
+  printf '%s\n%s\n' "$configuration_id" "$id" >"$state_file"
+  systemctl --user restart linux-wallpaperengine.service
+}
+
+cycle() {
+  local step="$1"
+  local current
+  local index=0
+  local next_index
+
+  current=$(current_id)
+  for i in "${!wallpaper_ids[@]}"; do
+    if [ "${wallpaper_ids[$i]}" = "$current" ]; then
+      index="$i"
+      break
+    fi
+  done
+
+  next_index=$(((index + step + ${#wallpaper_ids[@]}) % ${#wallpaper_ids[@]}))
+  select_id "${wallpaper_ids[$next_index]}"
+}
+
+load_playlist
+
+command="${1:-}"
+if [ -z "$command" ]; then
+  usage
+  exit 2
+fi
+shift
+
+case "$command" in
+select)
+  [ "$#" -eq 1 ] || {
+    usage >&2
+    exit 2
+  }
+  select_id "$1"
+  ;;
+next)
+  [ "$#" -eq 0 ] || {
+    usage >&2
+    exit 2
+  }
+  cycle 1
+  ;;
+previous)
+  [ "$#" -eq 0 ] || {
+    usage >&2
+    exit 2
+  }
+  cycle -1
+  ;;
+list)
+  [ "$#" -eq 0 ] || {
+    usage >&2
+    exit 2
+  }
+  current=$(current_id)
+  for id in "${wallpaper_ids[@]}"; do
+    if [ "$id" = "$current" ]; then
+      printf '* %s\n' "$id"
+    else
+      printf '  %s\n' "$id"
+    fi
+  done
+  ;;
+current)
+  [ "$#" -eq 0 ] || {
+    usage >&2
+    exit 2
+  }
+  current_id
+  ;;
+restart)
+  [ "$#" -eq 0 ] || {
+    usage >&2
+    exit 2
+  }
+  systemctl --user restart linux-wallpaperengine.service
+  ;;
+stop)
+  [ "$#" -eq 0 ] || {
+    usage >&2
+    exit 2
+  }
+  systemctl --user stop linux-wallpaperengine.service
+  ;;
+help | -h | --help)
+  usage
+  ;;
+*)
+  usage >&2
+  exit 2
+  ;;
+esac