PHP version switcher for macOS & homebrew

sphp.sh

# Switch PHP version
function sphp {
    # Option defaults
    INSTALL=0

    ARGS=()
    for i in "$@"; do
        case ${i} in
            -i|--install)
                INSTALL=1
                shift
                ;;
            *)
                if [[ $1 != -* ]]; then
                    ARGS+=("$1")
                fi

                shift
                ;;
        esac
    done
    set -- "${ARGS[@]}"

    current="$(php -r 'echo phpversion();' | cut -c1-3)"
    versions=("5.6" "7.0" "7.1" "7.2" "7.3");
    brewed=`brew info --installed --json | php -r '$json = json_decode(file_get_contents("php://stdin")); $php = array_map(function ($f) { foreach ($f->aliases as $a) { if (preg_match("/^php@(.+)/", $a, $m)) { return $m[1]; } } if (preg_match("/^php@(.+)/", $f->name, $m)) { return $m[1]; } }, $json); $php = array_filter($php); echo implode(" ", $php);'`
    brewable=`brew search '/^php@/' | grep php | php -r '$php = array_filter(preg_split("/[\\s\\n]+/", file_get_contents("php://stdin")), function ($f) { return substr($f, 0, 3) === "php"; }); $php = array_map(function ($f) { return str_replace("php@", "", $f); }, $php); echo implode(" ", $php);'`
    available=()
    installable=()
    unavailable=()

    for v in "${versions[@]}"; do
        skip=0

        for i in ${brewed}; do
            if [[ ${v} == ${i} ]]; then
                skip=1
                available+=(${v})

                break
            fi
        done

        for i in ${brewable}; do
            if [[ ${v} == ${i} ]]; then
                skip=1
                installable+=(${v})

                break
            fi
        done

        if [[ ${skip} == 0 ]]; then
            unavailable+=(${v})
        fi
    done

    if [[ -z "$1" ]]; then
        requested=${available[@]:(-1)}
        echo "Switching to the latested installed php formula: php@$requested"
    elif [[ "$1" == "latest" ]]; then
        requested=${installable[@]:(-1)}
    else
        requested="$1"
    fi

    if [[ ${requested} == ${current} ]]; then
        echo "$requested is already the current version"
        return
    fi

    for version in "${available[@]}"; do
        if [[ ${version} == ${requested} ]]; then
            brew unlink "php@$current" 2> /dev/null
            brew link --force "php@$requested"

            return
        fi
    done

    for version in "${installable[@]}"; do
        if [[ ${version} == ${requested} ]]; then
            if [[ ${INSTALL} == 1 ]]; then
                echo "Installing php@$requested"
                brew install "php@$requested"
                echo "Installed php@$requested"

                brew unlink "php@$current" 2> /dev/null
                brew link --force "php@$requested"

                return
            fi

            echo "php@$requested is not installed" >&2
            echo "Automatically install this version by running:" >&2
            echo "  sphp $requested --install" >&2
            return 1
        fi
    done

    echo "Could not find the formula php@$requested, make sure you have the required repository tapped" >&2
    return 1
}