Improve LXC template selection and cleanup hwaccel code

Enhanced the LXC container creation process to prompt for available template versions if the requested template is missing, allowing users to select from available options interactively. Also refactored the hardware acceleration setup function for better readability and consistency, and made minor whitespace and formatting adjustments.

misc/build.func

@@ -3052,9 +3052,78 @@ create_lxc_container() {
     TEMPLATE_BASE=$(awk -v s="$TEMPLATE_STORAGE" '$1==s {f=1} f && /path/ {print $2; exit}' /etc/pve/storage.cfg)
     [[ -n "$TEMPLATE_BASE" ]] && TEMPLATE_PATH="$TEMPLATE_BASE/template/cache/$TEMPLATE"
   fi
+
   [[ -n "$TEMPLATE_PATH" ]] || {
-    msg_error "Unable to resolve template path for $TEMPLATE_STORAGE. Check storage type and permissions."
-    exit 220
+    if [[ -z "$TEMPLATE" ]]; then
+      msg_error "Template ${PCT_OSTYPE} ${PCT_OSVERSION} not available"
+
+      # Get available versions
+      mapfile -t AVAILABLE_VERSIONS < <(
+        pveam available -section system 2>/dev/null |
+          grep "^${PCT_OSTYPE}-" |
+          sed -E 's/.*'"${PCT_OSTYPE}"'-([0-9]+\.[0-9]+).*/\1/' |
+          sort -V -u
+      )
+
+      if [[ ${#AVAILABLE_VERSIONS[@]} -gt 0 ]]; then
+        msg_info "Available versions:"
+        for i in "${!AVAILABLE_VERSIONS[@]}"; do
+          echo "  [$((i + 1))] ${AVAILABLE_VERSIONS[$i]}"
+        done
+
+        echo ""
+        read -p "Select version [1-${#AVAILABLE_VERSIONS[@]}] or Enter to exit: " choice
+
+        if [[ "$choice" =~ ^[0-9]+$ ]] && [[ "$choice" -ge 1 ]] && [[ "$choice" -le ${#AVAILABLE_VERSIONS[@]} ]]; then
+          export var_version="${AVAILABLE_VERSIONS[$((choice - 1))]}"
+          export PCT_OSVERSION="$var_version"
+          msg_ok "Switched to ${PCT_OSTYPE} ${var_version}"
+
+          # Retry template search with new version
+          TEMPLATE_SEARCH="${PCT_OSTYPE}-${PCT_OSVERSION:-}"
+          mapfile -t LOCAL_TEMPLATES < <(
+            pveam list "$TEMPLATE_STORAGE" 2>/dev/null |
+              awk -v s="$TEMPLATE_SEARCH" -v p="$TEMPLATE_PATTERN" '$1 ~ s && $1 ~ p {print $1}' |
+              sed 's|.*/||' | sort -t - -k 2 -V
+          )
+          mapfile -t ONLINE_TEMPLATES < <(
+            pveam available -section system 2>/dev/null |
+              sed -n "s/.*\($TEMPLATE_SEARCH.*$TEMPLATE_PATTERN.*\)/\1/p" |
+              sort -t - -k 2 -V
+          )
+          ONLINE_TEMPLATE=""
+          [[ ${#ONLINE_TEMPLATES[@]} -gt 0 ]] && ONLINE_TEMPLATE="${ONLINE_TEMPLATES[-1]}"
+
+          if [[ ${#LOCAL_TEMPLATES[@]} -gt 0 ]]; then
+            TEMPLATE="${LOCAL_TEMPLATES[-1]}"
+            TEMPLATE_SOURCE="local"
+          else
+            TEMPLATE="$ONLINE_TEMPLATE"
+            TEMPLATE_SOURCE="online"
+          fi
+
+          TEMPLATE_PATH="$(pvesm path $TEMPLATE_STORAGE:vztmpl/$TEMPLATE 2>/dev/null || true)"
+          if [[ -z "$TEMPLATE_PATH" ]]; then
+            TEMPLATE_BASE=$(awk -v s="$TEMPLATE_STORAGE" '$1==s {f=1} f && /path/ {print $2; exit}' /etc/pve/storage.cfg)
+            [[ -n "$TEMPLATE_BASE" ]] && TEMPLATE_PATH="$TEMPLATE_BASE/template/cache/$TEMPLATE"
+          fi
+
+          [[ -n "$TEMPLATE_PATH" ]] || {
+            msg_error "Template still not found after version change"
+            exit 220
+          }
+        else
+          msg_info "Installation cancelled"
+          exit 0
+        fi
+      else
+        msg_error "No ${PCT_OSTYPE} templates available"
+        exit 220
+      fi
+    else
+      msg_error "Unable to resolve template path for $TEMPLATE_STORAGE"
+      exit 220
+    fi
   }
 
   msg_ok "Template ${BL}$TEMPLATE${CL} [$TEMPLATE_SOURCE]"