#!/usr/bin/env bash

set -euo pipefail

if command -v greadlink >/dev/null; then
  bats_readlinkf() {
    greadlink -f "$1"
  }
else
  bats_readlinkf() {
    readlink -f "$1"
  }
fi

fallback_to_readlinkf_posix() {
  bats_readlinkf() {
    [ "${1:-}" ] || return 1
    max_symlinks=40
    CDPATH='' # to avoid changing to an unexpected directory

    target=$1
    [ -e "${target%/}" ] || target=${1%"${1##*[!/]}"} # trim trailing slashes
    [ -d "${target:-/}" ] && target="$target/"

    cd -P . 2>/dev/null || return 1
    while [ "$max_symlinks" -ge 0 ] && max_symlinks=$((max_symlinks - 1)); do
      if [ ! "$target" = "${target%/*}" ]; then
        case $target in
          /*) cd -P "${target%/*}/" 2>/dev/null || break ;;
          *) cd -P "./${target%/*}" 2>/dev/null || break ;;
        esac
        target=${target##*/}
      fi

      if [ ! -L "$target" ]; then
        target="${PWD%/}${target:+/}${target}"
        printf '%s\n' "${target:-/}"
        return 0
      fi

      # `ls -dl` format: "%s %u %s %s %u %s %s -> %s\n",
      #   <file mode>, <number of links>, <owner name>, <group name>,
      #   <size>, <date and time>, <pathname of link>, <contents of link>
      # https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ls.html
      link=$(ls -dl -- "$target" 2>/dev/null) || break
      target=${link#*" $target -> "}
    done
    return 1
  }
}

if ! BATS_PATH=$(bats_readlinkf "${BASH_SOURCE[0]}" 2>/dev/null); then
  fallback_to_readlinkf_posix
  BATS_PATH=$(bats_readlinkf "${BASH_SOURCE[0]}")
fi

export BATS_ROOT=${BATS_PATH%/*/*}
export -f bats_readlinkf
exec env BATS_ROOT="$BATS_ROOT" "$BATS_ROOT/libexec/bats-core/bats" "$@"