version/update system: version.sh, --update flag, UPDATE_MODULES, auto-detect existing install

lib/tui-fs.sh

@@ -182,3 +182,30 @@ tui_fs_confirm_start() {
   [[ "$response" =~ ^[yY](es)?$ ]]
   return $?
 }
+
+tui_fs_ask_update() {
+  local date="$1"
+  [[ "$TUI_FS_ACTIVE" -eq 0 ]] && return 1
+
+  tput cup 4 0 2>/dev/null || true
+  tput ed 2>/dev/null || true
+
+  printf '  \033[1;36m┌─\033[0m  \033[1;37mExisting Installation Found\033[0m\n'
+  printf '  \033[1;36m│\033[0m\n'
+  printf '  \033[1;36m│\033[0m  Installed: \033[1;37m%s\033[0m\n' "$date"
+  printf '  \033[1;36m│\033[0m  Update applies new dotfiles, packages and config\n'
+  printf '  \033[1;36m│\033[0m  without re-running GPU/fresh-install setup.\n'
+  printf '  \033[1;36m└─\033[0m\n'
+  printf '\n'
+  printf '  \033[1;36m?\033[0m  Update existing installation? \033[1m[Y/n]\033[0m '
+
+  if ((OMERON_HAS_GUM)); then
+    gum confirm "Update existing installation?"
+    return $?
+  fi
+
+  read -r response
+  response="${response:-Y}"
+  [[ "$response" =~ ^[yY](es)?$ ]]
+  return $?
+}

lib/version.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+OMERON_VERSION_DIR="${OMERON_VERSION_DIR:-$HOME/.local/share/omeron}"
+OMERON_VERSION_FILE="$OMERON_VERSION_DIR/version"
+
+version_read() {
+  if [[ -f "$OMERON_VERSION_FILE" ]]; then
+    source "$OMERON_VERSION_FILE"
+    return 0
+  fi
+  return 1
+}
+
+version_write() {
+  mkdir -p "$OMERON_VERSION_DIR"
+  cat > "$OMERON_VERSION_FILE" <<VERSION
+# Omeron Version File
+OMERON_VERSION=1
+OMERON_INSTALL_DATE="$(date '+%Y-%m-%d %H:%M:%S')"
+OMERON_LAST_UPDATE="$(date '+%Y-%m-%d %H:%M:%S')"
+VERSION
+}
+
+version_update() {
+  mkdir -p "$OMERON_VERSION_DIR"
+  if [[ -f "$OMERON_VERSION_FILE" ]]; then
+    local tmp
+    tmp="$(mktemp)"
+    while IFS= read -r line; do
+      case "$line" in
+        OMERON_LAST_UPDATE=*) printf 'OMERON_LAST_UPDATE="%s"\n' "$(date '+%Y-%m-%d %H:%M:%S')" ;;
+        *) printf '%s\n' "$line" ;;
+      esac
+    done < "$OMERON_VERSION_FILE" > "$tmp"
+    mv "$tmp" "$OMERON_VERSION_FILE"
+  else
+    version_write
+  fi
+}