Tailwind ERB preprocessor and watching tool

watch

#!/usr/bin/env sh

INPUT_FILE=""
OUTPUT_FILE=""
WATCH=false
TAILWIND=false
TAILWIND_FLAGS=""
LAST_MODIFIED=0

print_help() {
  echo "Usage: $0 -i <input_file> -o <output_file> [--watch] [--tailwind] [<tailwind_flags>]"
}

# Parse arguments
while [ "$#" -gt 0 ]; do
  case "$1" in
    -h|--help)
      print_help
      exit 0
      ;;
    -i|--input)
      INPUT_FILE="$2"
      shift 2
      ;;
    -o|--output)
      OUTPUT_FILE="$2"
      shift 2
      ;;
    --watch)
      WATCH=true
      shift
      ;;
    --tailwind)
      TAILWIND=true
      shift
      ;;
    *)
      # Collect all other arguments for Tailwind CLI
      TAILWIND_FLAGS="$TAILWIND_FLAGS $1"
      shift
      ;;
  esac
done

if [ -z "$INPUT_FILE" ] || [ -z "$OUTPUT_FILE" ]; then
  print_help
  exit 1
fi

if [ -n "$TAILWIND_FLAGS" ] && [ "$TAILWIND" != "true" ]; then
  echo "Warning: Use --tailwind to enable Tailwind CLI preprocessing."
fi

get_modified_time() {
  if command -v stat >/dev/null 2>&1; then
    if stat --version >/dev/null 2>&1; then
      stat -c %Y "$INPUT_FILE" 2>/dev/null
    else
      stat -f %m "$INPUT_FILE" 2>/dev/null
    fi
  else
    echo "0"
  fi
}

render_file() {
  CURRENT_MODIFIED=$(get_modified_time)
  if [ "$CURRENT_MODIFIED" -gt "$LAST_MODIFIED" ]; then
    echo "Rendering $INPUT_FILE..."

    if [ "$TAILWIND" = "true" ]; then
      # Memoize the original directory
      ORIGINAL_DIR=$(pwd)

      # Get absolute path of input file
      cd "$(dirname "$INPUT_FILE")" || exit 1
      ABS_INPUT_DIR=$(pwd)
      ABS_INPUT_FILE="$ABS_INPUT_DIR/$(basename "$INPUT_FILE")"

      # Ensure we operate from the original directory
      cd "$ORIGINAL_DIR" || exit 1
      cd "$(dirname "$OUTPUT_FILE")" || exit 1

      # Get absolute path of output file
      ABS_OUTPUT_DIR=$(pwd)
      ABS_OUTPUT_FILE="$ABS_OUTPUT_DIR/$(basename "$OUTPUT_FILE")"

      # Change to the input file's directory (if different)
      if [ "$ABS_INPUT_DIR" != "$ORIGINAL_DIR" ]; then
        cd "$ABS_INPUT_DIR" || exit 1
      fi

      # Run ERB and Tailwind processing
      erb "$ABS_INPUT_FILE" | npx @tailwindcss/cli -i - -o "$ABS_OUTPUT_FILE" $TAILWIND_FLAGS

      # Switch back to the original directory
      cd "$ORIGINAL_DIR" || exit 1
    else
      erb "$INPUT_FILE" > "$OUTPUT_FILE"
    fi

    LAST_MODIFIED="$CURRENT_MODIFIED"
  fi
}

if [ "$WATCH" = "true" ]; then
  echo "Watching $INPUT_FILE for changes..."
  while true; do
    render_file
    sleep 1
  done
else
  render_file
fi