function nvm --description "Node version manager"

    for silent in --silent -s

        if set --local index (contains --index -- $silent $argv)

            set --erase argv[$index] && break

        end

        set --erase silent

    end

    set --local cmd $argv[1]

    set --local ver $argv[2]

    if set --query silent && ! set --query cmd[1]

        echo "nvm: Version number not specified (see nvm -h for usage)" >&2

        return 1

    end

    if ! set --query ver[1] && contains -- "$cmd" install use

        for file in .nvmrc .node-version

            set file (_nvm_find_up $PWD $file) && read ver <$file && break

        end

        if ! set --query ver[1]

            echo "nvm: Invalid version or missing \".nvmrc\" file" >&2

            return 1

        end

    end

    set --local their_version $ver

    switch "$cmd"

        case -v --version

            echo "nvm, version 2.2.13"

        case "" -h --help

            echo "Usage: nvm install <version>    Download and activate the specified Node version"

            echo "       nvm install              Install the version specified in the nearest .nvmrc file"

            echo "       nvm use <version>        Activate the specified Node version in the current shell"

            echo "       nvm use                  Activate the version specified in the nearest .nvmrc file"

            echo "       nvm list                 List installed Node versions"

            echo "       nvm list-remote          List available Node versions to install"

            echo "       nvm list-remote <regex>  List Node versions matching a given regex pattern"

            echo "       nvm current              Print the currently-active Node version"

            echo "       nvm uninstall <version>  Uninstall the specified Node version"

            echo "Options:"

            echo "       -s, --silent             Suppress standard output"

            echo "       -v, --version            Print the version of nvm"

            echo "       -h, --help               Print this help message"

            echo "Variables:"

            echo "       nvm_arch                 Override architecture, e.g. x64-musl"

            echo "       nvm_mirror               Use a mirror for downloading Node binaries"

            echo "       nvm_default_version      Set the default version for new shells"

            echo "       nvm_default_packages     Install a list of packages every time a Node version is installed"

            echo "Examples:"

            echo "       nvm install latest       Install the latest version of Node"

            echo "       nvm use 14.15.1          Use Node version 14.15.1"

            echo "       nvm use system           Activate the system's Node version"

        case install

            _nvm_index_update

            string match --entire --regex -- (_nvm_version_match $ver) <$nvm_data/.index | read ver alias

            if ! set --query ver[1]

                echo "nvm: Invalid version number or alias: \"$their_version\"" >&2

                return 1

            end

            if test ! -e $nvm_data/$ver

                set --local os (command uname -s | string lower)

                set --local ext tar.gz

                set --local arch (command uname -m)

                switch $os

                    case aix

                        set arch ppc64

                    case sunos

                    case linux

                    case darwin

                    case {MSYS_NT,MINGW\*_NT}\*

                        set os win

                        set ext zip

                    case \*

                        echo "nvm: Unsupported operating system: \"$os\"" >&2

                        return 1

                end

                switch $arch

                    case i\*86

                        set arch x86

                    case x86_64

                        set arch x64

                    case arm64

                        string match --regex --quiet "v(?<major>\d+)" $ver

                        if test "$os" = darwin -a $major -lt 16

                            set arch x64

                        end

                    case armv6 armv6l

                        set arch armv6l

                    case armv7 armv7l

                        set arch armv7l

                    case armv8 armv8l aarch64

                        set arch arm64

                end

                set --query nvm_arch && set arch $nvm_arch

                set --local dir "node-$ver-$os-$arch"

                set --local url $nvm_mirror/$ver/$dir.$ext

                command mkdir -p $nvm_data/$ver

                if ! set --query silent

                    echo -e "Installing Node \x1b[1m$ver\x1b[22m $alias"

                    echo -e "Fetching \x1b[4m$url\x1b[24m\x1b[7m"

                end

                if ! command curl $silent --progress-bar --location $url |

                        command tar --extract --gzip --directory $nvm_data/$ver 2>/dev/null

                    command rm -rf $nvm_data/$ver

                    echo -e "\033[F\33[2K\x1b[0mnvm: Invalid mirror or host unavailable: \"$url\"" >&2

                    return 1

                end

                set --query silent || echo -en "\033[F\33[2K\x1b[0m"

                if test "$os" = win

                    command mv $nvm_data/$ver/$dir $nvm_data/$ver/bin

                else

                    command mv $nvm_data/$ver/$dir/* $nvm_data/$ver

                    command rm -rf $nvm_data/$ver/$dir

                end

            end

            if test $ver != "$nvm_current_version"

                set --query nvm_current_version && _nvm_version_deactivate $nvm_current_version

                _nvm_version_activate $ver

                set --query nvm_default_packages[1] && npm install --global $silent $nvm_default_packages

            end

            set --query silent || printf "Now using Node %s (npm %s) %s\n" (_nvm_node_info)

        case use

            test $ver = default && set ver $nvm_default_version

            _nvm_list | string match --entire --regex -- (_nvm_version_match $ver) | read ver __

            if ! set --query ver[1]

                echo "nvm: Can't use Node \"$their_version\", version must be installed first" >&2

                return 1

            end

            if test $ver != "$nvm_current_version"

                set --query nvm_current_version && _nvm_version_deactivate $nvm_current_version

                test $ver != system && _nvm_version_activate $ver

            end

            set --query silent || printf "Now using Node %s (npm %s) %s\n" (_nvm_node_info)

        case uninstall

            if test -z "$ver"

                echo "nvm: Not enough arguments for command: \"$cmd\"" >&2

                return 1

            end

            test $ver = default && test ! -z "$nvm_default_version" && set ver $nvm_default_version

            _nvm_list | string match --entire --regex -- (_nvm_version_match $ver) | read ver __

            if ! set -q ver[1]

                echo "nvm: Node version not installed or invalid: \"$their_version\"" >&2

                return 1

            end

            set --query silent || printf "Uninstalling Node %s %s\n" $ver (string replace ~ \~ "$nvm_data/$ver/bin/node")

            _nvm_version_deactivate $ver

            command rm -rf $nvm_data/$ver

        case current

            _nvm_current

        case ls list

            _nvm_list | _nvm_list_format (_nvm_current) $argv[2]

        case lsr {ls,list}-remote

            _nvm_index_update || return

            _nvm_list | command awk '

                FILENAME == "-" && (is_local[$1] = FNR == NR) { next } {

                    print $0 (is_local[$1] ? " ✓" : "")

                }

            ' - $nvm_data/.index | _nvm_list_format (_nvm_current) $argv[2]

        case \*

            echo "nvm: Unknown command or option: \"$cmd\" (see nvm -h for usage)" >&2

            return 1

    end

end

function _nvm_find_up --argument-names path file

    test -e "$path/$file" && echo $path/$file || begin

        test ! -z "$path" || return

        _nvm_find_up (string replace --regex -- '/[^/]*$' "" $path) $file

    end

end

function _nvm_version_match --argument-names ver

    string replace --regex -- '^v?(\d+|\d+\.\d+)$' 'v$1.' $ver |

        string replace --filter --regex -- '^v?(\d+)' 'v$1' |

        string escape --style=regex || string lower '\b'$ver'(?:/\w+)?$'

end

function _nvm_list_format --argument-names current regex

    command awk -v current="$current" -v regex="$regex" '

        $0 ~ regex {

            aliases[versions[i++] = $1] = $2 " " $3

            pad = (n = length($1)) > pad ? n : pad

        }

        END {

            if (!i) exit 1

            while (i--)

                printf((current == versions[i] ? " ▶ " : "   ") "%"pad"s %s\n",

                    versions[i], aliases[versions[i]])

        }

    '

end

function _nvm_current

    command --search --quiet node || return

    set --query nvm_current_version && echo $nvm_current_version || echo system

end

function _nvm_node_info

    set --local npm_path (string replace bin/npm-cli.js "" (realpath (command --search npm)))

    test -f $npm_path/package.json || set --local npm_version_default (command npm --version)

    command node --eval "

        console.log(process.version)

        console.log('$npm_version_default' ? '$npm_version_default': require('$npm_path/package.json').version)

        console.log(process.execPath)

    " | string replace -- ~ \~

end