#!/usr/bin/env bash

set -e

NODE_VERSION=${NODE_VERSION:-v12.16.2}

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 ${NODE_PREFIX_DIR}
[[ -s current ]] && sudo unlink current
sudo ln --symbolic "${NODE_VERSION}" current
echo current version set to "${NODE_VERSION}"
cd ${BIN_DIR}
for bin in "${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