#!/usr/bin/env bash
# =============================================================================
# skills/ingest/scripts/slug.sh
# Derive a wiki slug from a path, filename, or title string.
#   slug.sh "raw/articles/My Source.md"  -> my-source
#   slug.sh "Some Concept Name"          -> some-concept-name
# =============================================================================
set -euo pipefail

input="${1:?usage: slug.sh <path-or-title>}"

# Strip directory and extension when given a path
base="${input##*/}"
base="${base%.*}"

slug="$(printf '%s\n' "$base" \
  | tr '[:upper:]' '[:lower:]' \
  | sed -E 's/[^a-z0-9]+/-/g; s/-{2,}/-/g; s/^-+//; s/-+$//')"

# An all-symbols input (e.g. "!!!.md") collapses to "" — refuse rather than emit a
# broken/empty slug that would produce an invalid branch name downstream.
[[ -n "$slug" ]] || { echo "slug: empty result for input '${input}'" >&2; exit 1; }
printf '%s\n' "$slug"