#!/bin/bash

# Enable the following for debugging purpose
# set -vx

#
# Resolves any path (even through link-chains etc. to an absolute path.
#
# Usage:
#   MY_COMMAND="$(resolvePath "${0}")"
#   MY_DIR="$(dirname "${MY_COMMAND}")"
#
function resolvePath() {
  local path="${1}"

  firstTry="$(readlink -f "${path}" 2> /dev/null)"
  if [ -n "${firstTry}" ]; then
    echo "${firstTry}"
  else
    echo "$(_pwdResolvePath "${path}")"
  fi
}

#
# If readlink is not available on the system the fallback is to use
# pwd -P and the "cd"-approach to resolve a symbolic link.
#
function _pwdResolvePath() {
  local path="${1}"
  local cmd dir link

  if [ -d "${path}" ]; then
    cmd=
    dir="${path}"
  else
    cmd="$(basename "${path}")"
    dir="$(dirname "${path}")"
  fi

  cd "$dir"

  if [ ! -d "${path}" ]; then
    while [ -h "$cmd" ]; do
      link="$(ls -l "$cmd" | cut -d\> -f2 | cut -c2-)"
      cmd="$(basename "$link")"
      dir="$(dirname "$link")"
      cd "$dir"
    done
    cmd="/${cmd}"
  fi

  echo "$(pwd -P)${cmd}"
}

echo "$(resolvePath "${1}")"