#!/usr/bin/env bash

#
# Regular commands can be executed as
#
#     sudo nvm-exec [-v 6.9.2] npm install -g npm
#
# If no -v option provided, then try to use $NODE_VERSION, .nvmrc, default, and finally current
#
# When using sudo, use "sudo -E" to preserve env to pass NODE_VERSION.
#
# nvm commands can be executed as
#
#     sudo nvm-exec nvm install 6.9.2
#     sudo nvm-exec nvm alias default 6.9.2
#

function nvm_fail() {
  echo "$1" >&2
  exit 127
}

has_realpath=""

function find_nvm_dir() {
  if which realpath >& /dev/null; then
    has_realpath=yes
    dirname "$(realpath "$0")"
  else
    command cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd
  fi
}

DIR="$(find_nvm_dir)"

function check_nvm_sh() {
  if [ ! -f "$DIR/nvm.sh" ]; then
    local rp_msg=""
    [ "$has_realpath" == "yes" ] || rp_msg="; missing realpath command for finding nvm-exec's realpath to search for nvm.sh"
    nvm_fail "Unable to find nvm.sh at $DIR$rp_msg"
  fi
}

check_nvm_sh

function nvm_use() {
  nvm use "$1" > /dev/null || nvm_fail "nvm use $2 failed"
}

function nvm_use_v() {
  [ -n "$1" ] && nvm_use "$1" "$2"
}

opt_version=""

if [ "$1" == "-v" ]; then
  shift
  opt_version=$1
  shift
fi

function check_version() {
  nvm_use_v "$opt_version" "(-v $opt_version)" && return
  nvm_use_v "$NODE_VERSION" "(NODE_VERSION $NODE_VERSION)" && return

  local nvmrc
  nvmrc=$(nvm which 2>&1 | grep ^Found | grep -o "\'.*\.nvmrc\'")
  [ -n "$nvmrc" ] && nvm_use "" "with $nvmrc file" && return

  nvm which default >& /dev/null && nvm_use_v default default && return
  nvm which current >& /dev/null && nvm_use_v current current && return

  nvm_fail "No -v option or NODE_VERSION provided; no .nvmrc file, no default, and no current found"
}

# shellcheck disable=SC1090
\. "$DIR/nvm.sh" --no-use

if [ "$1" == "nvm" ]; then
  eval "$@"
else
  check_version
  exec "$@"
fi