generate-group.sh

#!/usr/bin/env bash
set -euo pipefail

group="${1:-}"

if [[ -z "$group" ]]; then
  echo "Usage: $0 <package-group>" >&2
  exit 1
fi

base_dir="${ARCH_CONFIG_DIR:-$HOME/.config/arch-config}"
modules_dir="$base_dir/modules/groups"
out_file="$modules_dir/$group.yaml"

# Fail early if the base config dir is missing.
if [[ ! -d "$base_dir" ]]; then
  cat >&2 <<EOF
Error: Base directory not found: $base_dir

Create it first, or set ARCH_CONFIG_DIR to your correct location.

Example:
  mkdir -p "$base_dir"
or:
  ARCH_CONFIG_DIR=/path/to/arch-config $0 "$group"
EOF
  exit 2
fi

# Create modules/groups if needed.
mkdir -p "$modules_dir"

# If output exists, prompt before overwriting.
if [[ -e "$out_file" ]]; then
  printf "File already exists: %s\nUpdate it? [y/N]: " "$out_file" >&2
  read -r reply
  reply="${reply,,}" # lowercase
  if [[ "$reply" != "y" && "$reply" != "yes" ]]; then
    echo "Canceled. Left file unchanged." >&2
    exit 0
  fi
fi

# Query packages in the group.
if ! pkgs="$(pacman -Sg "$group" 2>/dev/null | awk '{print $2}')"; then
  echo "Error: Failed to query pacman group: $group" >&2
  exit 3
fi

if [[ -z "$pkgs" ]]; then
  echo "Error: No packages found for group '$group' (or group does not exist)." >&2
  exit 4
fi

# Write to a temp file then move into place (avoids partial writes).
tmp="$(mktemp)"
trap 'rm -f "$tmp"' EXIT

{
  printf 'description: %s package group\n\n' "$group"
  printf 'packages:\n'
  while IFS= read -r pkg; do
    [[ -n "$pkg" ]] || continue
    printf '  - %s\n' "$pkg"
  done <<< "$pkgs"
} > "$tmp"

mv -f "$tmp" "$out_file"
trap - EXIT

echo "Wrote: $out_file"