GVM version switcher for Grails 2.x and 3.x

grails-switcher.sh

if [ `basename $SHELL` = "zsh" ]; then
    if which gvm >/dev/null 2>&1; then
        __gvm_switch_grails_griffon() {
            # for 2.x
            if [ -s "application.properties" ]; then
                local array candidate target current
                array=($(cat application.properties | grep --color=never 'app.\(grails\|griffon\).version' | sed -E "s|app.(.*).version=(.*)|\1 \2|g" | tr -d "\r\n"))
                candidate=${array[1]}
                target=${array[2]}
                current=$((gvm offline enable >/dev/null && gvm current ${candidate} && gvm offline disable > /dev/null) | awk '{ print $4 }')
                if [[ $current != $target ]]; then
                    echo "Switching to $candidate $target from $current..."
                    gvm use $candidate $target
                fi
            fi
            # for 3.x
            if [ -s "gradle.properties" ] && [ -d "grails-app" ]; then
                local array candidate target current
                array=($(cat gradle.properties | grep --color=never 'grailsVersion=' | sed -E "s|grailsVersion=(.*)|\1|g" | tr -d "\r\n"))
                candidate=grails
                target=${array[1]}
                current=$((gvm offline enable >/dev/null && gvm current ${candidate} && gvm offline disable > /dev/null) | awk '{ print $4 }')
                if [[ $current != $target ]]; then
                    echo "Switching to $candidate $target from $current..."
                    gvm use $candidate $target
                fi
            fi
        }
        add-zsh-hook chpwd __gvm_switch_grails_griffon
    fi
fi