[Shell command proxy] Lazy initialization of heavy tool (SDKMAN!) + interception of `sdk use java` to fuzzy filter installed versions when none specified. #shell

sdkman.sh

export SDKMAN_DIR="/usr/local/sdkman"

# https://mharrison.org/post/bashfunctionoverride/
copy_function() {
	local orig_fn=$(declare -f $1)
	local new_fn="$2${orig_fn#$1}"
	eval "$new_fn"
}

sdk_fuzzy_find_local_version() {
	local candidate=$1
	__sdkman_build_version_csv $candidate | tr ',' '\n' | sort -r -n | 
    	fzf -d '\.' --nth 1  # filter by major version
}

is_loaded() {
	(( ${+SDKMAN_VERSION} ))
}

init() {
	source "${SDKMAN_DIR}/bin/sdkman-init.sh"
	copy_function sdk sdk_orig   # `sdk` is not actually a shell command but a function
	copy_function sdk_proxy sdk  # reinject proxy after initialization
}

lazy_init() {
	is_loaded || init
}

# https://frederic-hemberger.de/articles/speed-up-initial-zsh-startup-with-lazy-loading/
sdk_proxy() {
	lazy_init
    
	if (( $# == 2 )) && [[ $1 =~ ^(u|use)$ ]]; then  # proxied subcommand
		local candidate=$2
		sdk_orig use $candidate $(sdk_fuzzy_find_local_version $candidate)
	else
    	# every other use of sdk goes through the original command
		sdk_orig "$@"
	fi
}

copy_function sdk_proxy sdk  # inject proxy