wnv

#!/bin/bash

########### what-node-version #################
#
# Script for automatically switch node versions based on the configured engine in the package.json
# Author: Luis Beu
#
####################################################

# print usage page
usage() {
    cat <<EOF
Usage: wnv [NPPM OPTIONS...]
  -h  --help                      Show this usage summary and exit

NO_CACHE=1 wnv [NPPM OPTIONS...]
  pulls the node version cache again
EOF
    exit 0
}

# TODO: verbose and silence nvm

# if no args print usage
if [ $# -eq 0 ]; then
    usage
fi

# loop over flags
while test $# -gt 0; do
    case "$1" in
    -h | --help)
        usage
        ;;
    *)
        break
        ;;
    esac
done

if [ ! -f /usr/local/opt/nvm/nvm.sh ]; then
    echo "nvm not found please install it. brew install nvm"
    exit 1
fi

# source nvm
source /usr/local/opt/nvm/nvm.sh

padding=10000
script_dir=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
version_dir="$script_dir/versions.txt"

if [[ ! -e 'package.json' ]]; then
    npm "$@"
    exit 0
fi

engines=$(jq '.engines.node' -r package.json)

# no configuration found dont switch version
if [[ -z $engines ]] || [[ $engines == "null" ]] ; then
    npm "$@"
    exit 0
fi

if [[ ! -e $version_dir ]]; then
    NO_CACHE=1
fi

# get engine config from package.json
node_version=($(grep -Eo '[0-9]+\.[0-9]+\.[0-9]+' <<<"$engines"))

# read versions new if file is older then 24h or no_cache is set
if [[ -n $NO_CACHE ]] || test "$(find "$version_dir" -mmin +1440)"; then
    echo "Fetch node versions. This takes a little..."

    # curl version list from nodejs dist index
    version_list=($(curl --silent https://nodejs.org/dist/ | grep -o 'href=".*">' | sed 's/href="//;s/v//;s/\///;s/">//'))

    for index in "${!version_list[@]}"; do
        # test if it is version
        if [[ "${version_list[index]}" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
            # split version into subversions
            read -ra split <<<$(
                IFS="."
                echo ${version_list[index]}
            )
            # add padding for right sorting
            for i in "${!split[@]}"; do
                split[$i]=$((${split[$i]} + $padding))
            done

            # put array back together
            version_list[$index]=$(printf "%s." "${split[@]}" | cut -d "." -f 1-${#split[@]})
        else
            # unset all that is not considered a version
            unset -v 'version_list[$index]'
        fi
    done

    # sort array
    version_list=("${version_list[@]}")
    IFS=$'\n' version_list=($(sort <<<"${version_list[*]}"))
    unset IFS

    for index in "${!version_list[@]}"; do
        # split version into subversions
        read -ra split <<<$(
            IFS="."
            echo ${version_list[index]}
        )
        # remove padding
        for i in "${!split[@]}"; do
            split[$i]=$((${split[$i]} - $padding))
        done
        # put array back together
        version_list[$index]=$(printf "%s." "${split[@]}" | cut -d "." -f 1-${#split[@]})
    done

    # write to file to be a little faster
    printf "%s\n" "${version_list[@]}" >"$version_dir"
else
    # usign cached version
    version_list=($(cat "$version_dir" | tr '\n' ' '))
fi

# check if specified version is a legit version
if [[ ! " ${version_list[*]} " =~ ${node_version[0]} ]]; then
    echo "Unkonw node version specefied in package.json"
    exit 1
fi

# check what to do and which version to use/install
case $engines in

*">"*)
    node_versio_majorn=($(grep -Eo '^\d+' <<<"${node_version[0]}"))
    nvm install "${node_versio_majorn[0]}"
    npm "$@"
    ;;

*"<"*)
    if [[ $engines == *"="* ]]; then
        nvm install "${node_version[0]}"
        npm "$@"
        exit 0
    fi
    # get index from version
    for index in "${!version_list[@]}"; do
        [[ "${version_list[$index]}" = "${node_version[0]}" ]] && break
    done

    # use the version previous to specified
    nvm install "${version_list[$index - 1]}"
    npm "$@"
    ;;

*"="*)
    nvm install "${node_version[0]}"
    npm "$@"
    ;;

*)
    nvm install "${node_version[0]}"
    npm "$@"
    ;;
esac

# exit script successful
exit 0