Add asset backup script with zstd/pigz/gzip fallback

tools/backup_assets.sh

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+#
+# Backup extracted WoW assets (Data/) to a compressed archive.
+# Usage: ./tools/backup_assets.sh [DATA_DIR] [BACKUP_DIR]
+#
+# If not provided, the script will prompt for both paths.
+
+set -euo pipefail
+
+DEFAULT_DATA="./Data"
+DEFAULT_BACKUP="$HOME/.local/share/wowee/backups"
+
+# --- Resolve data directory ---
+DATA_DIR="${1:-}"
+if [ -z "$DATA_DIR" ]; then
+    read -rp "Data directory to back up [$DEFAULT_DATA]: " DATA_DIR
+    DATA_DIR="${DATA_DIR:-$DEFAULT_DATA}"
+fi
+
+if [ ! -d "$DATA_DIR" ]; then
+    echo "Error: Data directory not found: $DATA_DIR" >&2
+    exit 1
+fi
+
+if [ ! -f "$DATA_DIR/manifest.json" ]; then
+    echo "Error: No manifest.json in $DATA_DIR — doesn't look like an extracted asset directory" >&2
+    exit 1
+fi
+
+# --- Resolve backup directory ---
+BACKUP_DIR="${2:-}"
+if [ -z "$BACKUP_DIR" ]; then
+    read -rp "Backup destination [$DEFAULT_BACKUP]: " BACKUP_DIR
+    BACKUP_DIR="${BACKUP_DIR:-$DEFAULT_BACKUP}"
+fi
+
+mkdir -p "$BACKUP_DIR"
+
+# --- Build archive name with timestamp ---
+TIMESTAMP=$(date +%Y%m%d_%H%M%S)
+ARCHIVE="$BACKUP_DIR/wowee_assets_$TIMESTAMP.tar.zst"
+
+# --- Measure source size ---
+DATA_SIZE=$(du -sh "$DATA_DIR" | cut -f1)
+echo "Backing up $DATA_DIR ($DATA_SIZE) ..."
+echo "Destination: $ARCHIVE"
+
+# --- Compress ---
+if command -v zstd &>/dev/null; then
+    tar cf - -C "$(dirname "$DATA_DIR")" "$(basename "$DATA_DIR")" | zstd -T0 -3 -o "$ARCHIVE"
+elif command -v pigz &>/dev/null; then
+    ARCHIVE="$BACKUP_DIR/wowee_assets_$TIMESTAMP.tar.gz"
+    tar cf - -C "$(dirname "$DATA_DIR")" "$(basename "$DATA_DIR")" | pigz -p "$(nproc)" > "$ARCHIVE"
+else
+    ARCHIVE="$BACKUP_DIR/wowee_assets_$TIMESTAMP.tar.gz"
+    tar czf "$ARCHIVE" -C "$(dirname "$DATA_DIR")" "$(basename "$DATA_DIR")"
+fi
+
+ARCHIVE_SIZE=$(du -sh "$ARCHIVE" | cut -f1)
+echo "Done: $ARCHIVE ($ARCHIVE_SIZE)"