# ncli/commands/rebuild.nix — Rebuild + Update logic
lib: let
  inherit (lib) host project handle_backups handle_build_error;
in rec {
  # Shared rebuild snippet used by both `rebuild` and `update`
  rebuild_logic = ''
    handle_backups
    geno=$(sudo nix-env --list-generations --profile /nix/var/nix/profiles/system | grep current | awk '{print $1}')
    cd "$HOME/${project}" || { echo "Error: Could not change to $HOME/${project}"; exit 1; }

    current=""
    if [ -f /etc/nixos-tags ]; then
      current=$(cat /etc/nixos-tags)
    fi
  '';

  rebuild_case = ''
    ${rebuild_logic}
    echo -e "Starting NixOS rebuild for current host: ${host} on generation: $YELLOW$geno$NOCOLOR"

    set +e
    sudo nixos-rebuild switch --flake .
    _rebuild_exit=$?
    set -e
    if [ "$_rebuild_exit" -eq 0 ]; then
      echo "✓ Rebuild finished successfully for ${host}"

      if [ -n "$current" ]; then
        sudo /run/current-system/specialisation/"$current"/bin/switch-to-configuration test
      else
        echo "No specialization tag found, staying on default system."
      fi

      genn=$(sudo nix-env --list-generations --profile /nix/var/nix/profiles/system | grep current | awk '{print $1}')
      echo -e "Running on new generation: $YELLOW $geno $NOCOLOR-> $GREEN$genn$NOCOLOR"
    else
      ( exit "$_rebuild_exit" ); handle_build_error
      echo "✗ Rebuild failed for ${host}" >&2
      exit 1
    fi
  '';

  update_case = ''
    ${rebuild_logic}
    echo -e "Updating flake and rebuilding system for current host: ${host} on generation: $YELLOW$geno$NOCOLOR"

    # --- Selective flake update ---
    read -rp "Update [a]ll inputs or [s]elect manually? (a/s): " choice

    case "$choice" in
      a|A)
        echo "Updating all inputs..."
        if nix flake update --flake .; then
          echo "✓ Flake updated successfully"
        else
          echo "✗ Flake update failed" >&2
          exit 1
        fi
        ;;
      s|S)
        echo "Fetching available updates (this may take a moment)..."
        TEMP_LOCK=$(mktemp)
        trap 'rm -f "$TEMP_LOCK"' EXIT

        nix flake update --output-lock-file "$TEMP_LOCK" --flake . 2>/dev/null

        outdated=$(jq -r --slurpfile new "$TEMP_LOCK" '
          .nodes as $old |
          $new[0].nodes as $newn |
          ($old | keys[]) |
          select(. != "root") |
          select(
            ($old[.].locked.lastModified // 0) !=
            ($newn[.].locked.lastModified // 0)
          )
        ' flake.lock)

        if [[ -z "$outdated" ]]; then
          echo "✓ All inputs are already up to date, skipping flake update."
        else
          echo
          echo "Updates available for:"
          printf '%s\n' "$outdated"
          echo
          echo "Tab to select, Enter to update, Esc to cancel."
          selected=$(printf '%s\n' "$outdated" | fzf --multi) || {
            echo "No inputs selected, skipping flake update."
            selected=""
          }
          if [[ -n "$selected" ]]; then
            if nix flake update --flake . $selected; then
              echo "✓ Flake updated successfully"
            else
              echo "✗ Flake update failed" >&2
              exit 1
            fi
          fi
        fi
        ;;
      *)
        echo "Invalid choice, skipping flake update."
        ;;
    esac
    # --- End selective flake update ---

    if [ -n "$current" ]; then
      echo "Rebuilding system... Current specialization: $current"
    else
      echo "Rebuilding system... Staying on current specialization"
    fi

    set +e
    sudo nixos-rebuild switch --flake .
    _rebuild_exit=$?
    set -e
    if [ "$_rebuild_exit" -eq 0 ]; then
      echo "✓ Update and rebuild finished successfully for ${host}"

      if [ -n "$current" ]; then
        sudo /run/current-system/specialisation/"$current"/bin/switch-to-configuration test
      else
        echo "No specialization tag found, staying on default system."
      fi

      genn=$(sudo nix-env --list-generations --profile /nix/var/nix/profiles/system | grep current | awk '{print $1}')
      echo -e "Running on new generation: $YELLOW $geno $NOCOLOR-> $GREEN$genn$NOCOLOR"
    else
      ( exit "$_rebuild_exit" ); handle_build_error
      echo "✗ Update and rebuild failed for ${host}" >&2
      exit 1
    fi
  '';
}