Add a machine-wide uninstaller and the empty-directory rule

A store's own engine can take that store away. What was missing was a way to
take the framework off a machine without having to remember what is on it:
uninstall.sh finds every store home under both known roots, has each store's
own engine purge what it installed, and then removes the store, its launcher,
its Ports entry and the engine files.

It delegates the removing rather than repeating it, because only the engine's
state.json knows which ROMs, playlists, thumbnails or gamelist entries were a
store's. If an engine cannot finish — RetroArch running, a ROMs root unmounted
— the run stops there instead of deleting the engine that knew what it had
installed.

POSIX sh, not bash, so `curl … | sh` works on a machine whose /bin/sh is dash;
checked with dash. `prune_empty_dirs` moves here for the same reason the delete
guard `within()` did: both engines need it, and both need it to be careful. It
removes only directories that are actually empty, and only inside the subtree
the store owns, so one surprise file is enough to keep a directory.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

uninstall.sh

@@ -0,0 +1,118 @@
+#!/bin/sh
+# Remove every WarpEngine store from this machine — the games, the store
+# engines, this shared core and the launchers.
+#
+#   curl -fsSL https://git.teletypegames.org/engines/warpstore/raw/branch/master/uninstall.sh | sh
+#
+# A single store is better removed by its own engine's uninstaller, which knows
+# that host's extras (a Batocera Ports entry, say). This one is for taking the
+# whole framework off a machine without having to remember what is installed:
+# it finds every store home under the known roots, has each store's own engine
+# purge what it installed, and then deletes the store.
+#
+#   DRY_RUN=1   print what would go, remove nothing
+#   KEEP_GAMES=1  leave the installed games alone, remove only the scripts
+#   FORCE=1     purge even while RetroArch is running
+#
+# POSIX sh on purpose: `| sh` has to work on a machine whose /bin/sh is dash.
+set -eu
+
+BATOCERA_STORE_ROOT="${BATOCERA_STORE_ROOT:-/userdata/system/batocera-store}"
+BATOCERA_PORTS_DIR="${BATOCERA_PORTS_DIR:-/userdata/roms/ports}"
+STORE_ROOT="${STORE_ROOT:-${XDG_DATA_HOME:-$HOME/.local/share}/warp-engine-store}"
+BIN_DIR="${BIN_DIR:-$HOME/.local/bin}"
+DRY_RUN="${DRY_RUN:-0}"
+KEEP_GAMES="${KEEP_GAMES:-0}"
+FORCE="${FORCE:-0}"
+
+say() { echo "[uninstall-all] $*"; }
+run() {
+  if [ "$DRY_RUN" = "1" ]; then echo "[uninstall-all] would: $*"; else "$@"; fi
+}
+
+command -v python3 >/dev/null 2>&1 || {
+  echo "[uninstall-all] error: python3 is required to ask the engines what they installed" >&2
+  exit 1
+}
+
+FOUND=0
+
+# `purge` is the engine's own "remove everything I installed": the shell has no
+# way of knowing which ROMs, playlists, thumbnails or gamelist entries were a
+# store's, and state.json does.
+purge_store() {  # purge_store <store home> <engine file> <home env var> <extra flag>
+  home="$1"; engine="$2"; homevar="$3"; extra="$4"
+  if [ "$KEEP_GAMES" = "1" ]; then
+    say "keeping the games of '$(basename "$home")' (KEEP_GAMES=1)"
+    return 0
+  fi
+  if [ ! -f "$home/$engine" ] || [ ! -f "$home/config.json" ]; then
+    say "warning: no engine in $home — its games have to go by hand"
+    return 0
+  fi
+  dry=""
+  [ "$DRY_RUN" = "1" ] && dry="--dry-run"
+  # shellcheck disable=SC2086
+  env "$homevar=$home" python3 "$home/$engine" --config "$home/config.json" $dry purge $extra || {
+    say "error: the engine in $home could not finish — stopping before anything else is removed."
+    say "       Close RetroArch (or FORCE=1), fix what it reported, and run this again."
+    exit 1
+  }
+}
+
+# --- Batocera stores -------------------------------------------------------
+if [ -d "$BATOCERA_STORE_ROOT" ]; then
+  for home in "$BATOCERA_STORE_ROOT"/*/; do
+    [ -f "$home/config.json" ] || continue
+    id="$(basename "$home")"
+    FOUND=$((FOUND + 1))
+    say "batocera store '$id' in $home"
+    purge_store "${home%/}" store.py BATOCERA_STORE_HOME ""
+
+    # The Ports entry's name is whatever the store repository chose, not
+    # store.name — but it always runs this store's launcher, so it is found by
+    # looking inside the scripts rather than by guessing a file name.
+    if [ -d "$BATOCERA_PORTS_DIR" ]; then
+      for entry in "$BATOCERA_PORTS_DIR"/*.sh; do
+        [ -f "$entry" ] || continue
+        if grep -q -F "${home%/}" "$entry" 2>/dev/null; then
+          run rm -f "$entry"
+        fi
+      done
+    fi
+    run rm -f "$BATOCERA_STORE_ROOT/$id-store"
+    run rm -rf "${home%/}"
+  done
+  [ "$DRY_RUN" = "1" ] || rmdir "$BATOCERA_STORE_ROOT" 2>/dev/null || true
+fi
+
+# --- RetroArch stores ------------------------------------------------------
+if [ -d "$STORE_ROOT" ]; then
+  extra=""
+  [ "$FORCE" = "1" ] && extra="--force"
+  for home in "$STORE_ROOT"/*/; do
+    [ -f "$home/config.json" ] || continue
+    id="$(basename "$home")"
+    FOUND=$((FOUND + 1))
+    say "retroarch store '$id' in $home"
+    purge_store "${home%/}" retroarch_store.py RETROARCH_STORE_HOME "$extra"
+    run rm -f "$BIN_DIR/$id-retroarch-store"
+    run rm -rf "${home%/}"
+  done
+  [ "$DRY_RUN" = "1" ] || rmdir "$STORE_ROOT" 2>/dev/null || true
+fi
+
+if [ "$FOUND" = "0" ]; then
+  say "no WarpEngine store found. Looked in:"
+  say "  $BATOCERA_STORE_ROOT"
+  say "  $STORE_ROOT"
+  say "Point at them with BATOCERA_STORE_ROOT / STORE_ROOT if they live elsewhere."
+  exit 0
+fi
+
+if [ "$DRY_RUN" = "1" ]; then
+  say "dry run — nothing was removed ($FOUND store(s) found)."
+else
+  say "done: $FOUND store(s) removed, engines and the shared core with them."
+  say "Restart EmulationStation or RetroArch to see the games go."
+fi