#!/usr/bin/env bash

set -e

NODE_VERSION=${NODE_VERSION:-v12.16.1}

PREFIX_DIR=/usr/local
BIN_DIR=${PREFIX_DIR}/bin

NODE_PREFIX_DIR=${PREFIX_DIR}/node
NODE_DEST_DIR=${NODE_PREFIX_DIR}/${NODE_VERSION}
NODE_DEST_BIN_DIR=${NODE_DEST_DIR}/bin
NODE_CURRENT=${NODE_PREFIX_DIR}/current

OS=
if [[ $OSTYPE =~ linux ]]; then
    OS=linux
elif [[  $OSTYPE =~ darwin ]]; then
    OS=darwin
else
    echo unknown os: $OSTYPE
    exit 1
fi

ARCH=
if [[ $(uname -m) == x86_64 ]]; then
    ARCH=x64
else
    echo arch not yet supported: $(uname -m)
    exit 1
fi

[[ -d ${NODE_DEST_DIR} ]] || sudo mkdir -p ${NODE_DEST_DIR}

TMP_DIR=
if [[ ! -d ${NODE_DEST_BIN_DIR} ]]; then
    TMP_DIR=$(mktemp --directory)
    DEST_FILE=$TMP_DIR/node.tar.xz
    URL=https://nodejs.org/dist/${NODE_VERSION}/node-${NODE_VERSION}-${OS}-${ARCH}.tar.xz
    echo downloading node $NODE_VERSION to temp directory ${TMP_DIR}
    curl --silent --output ${DEST_FILE} ${URL}

    sudo tar xf ${DEST_FILE} --directory ${NODE_DEST_DIR} --strip-components 1
    sudo chown --recursive root:root ${NODE_DEST_DIR}
else
    echo node $NODE_VERSION already installed
fi

cd ${NODE_PREFIX_DIR}
sudo unlink current
sudo ln --symbolic ${NODE_VERSION} current
echo current version set to ${NODE_VERSION}
cd ${BIN_DIR}
for bin in $(ls ${NODE_CURRENT}/bin); do
    [[ -s $bin ]] || sudo ln --symbolic ${NODE_CURRENT}/bin/$bin
done

if [[ $TMP_DIR != "" ]]; then
    rm -rf ${TMP_DIR}
    echo removed up temp directory ${TMP_DIR}
fi