#!/bin/sh -l

slug_ref() {
  echo "$1" |
    tr "[:upper:]" "[:lower:]" |
    sed -r 's#refs/[^\/]*/##;s/[~\^]+//g;s/[^a-zA-Z0-9]+/-/g;s/^-+\|-+$//g;s/^-*//;s/-*$//' |
    cut -c1-63
}

short_sha() {
  echo "$1" |
    cut -c1-8
}

{
  echo "GITHUB_REF_SLUG=$(slug_ref "$GITHUB_REF")"
  echo "GITHUB_HEAD_REF_SLUG=$(slug_ref "$GITHUB_HEAD_REF")"
  echo "GITHUB_BASE_REF_SLUG=$(slug_ref "$GITHUB_BASE_REF")"
  echo "GITHUB_SHA_SHORT=$(short_sha "$GITHUB_SHA")"
} >>"$GITHUB_ENV"