#!/usr/bin/env bash
# normalize-noise-patterns.sh
#
# Read a log-noise.patterns file and emit a normalized stream of patterns
# that is safe to feed into `grep -Eaif`.
#
# Behaviour:
#   - Lines starting with `#` (after optional leading whitespace) are dropped.
#   - Empty / whitespace-only lines are dropped.
#   - Leading and trailing whitespace is trimmed from each pattern.
#   - Patterns that become empty after trimming are dropped.
#
# Why this exists:
#   A single empty / whitespace-only line in the input file would make
#   `grep -Eaif` match every input line, silently wiping the entire log
#   highlights signal. Always pipe patterns through this normalizer first.
#
# Usage:
#   normalize-noise-patterns.sh <file>
#   cat patterns | normalize-noise-patterns.sh
set -euo pipefail

src="${1:-/dev/stdin}"

grep -Ev '^[[:space:]]*(#|$)' "$src" \
  | sed -E 's/^[[:space:]]+//; s/[[:space:]]+$//' \
  | grep -v '^$' || true