#!/bin/sh
# vim:set filetype=sh:

set -e

if [ -n "${DEBUG}" ]; then
	set -x
fi

_fetch() {
	if [ "$CURL" != "no" ] && command -v "$CURL" >/dev/null 2>&1; then
		"$CURL" -sSLf "$@"
	elif [ "$WGET" != "no" ] && command -v "$WGET" >/dev/null 2>&1; then
		"$WGET" -q -O - "$@"
	else
		echo "Error: neither curl nor wget is available" >&2
		exit 1
	fi
}

_k0s_latest() {
	_fetch "https://docs.k0sproject.io/stable.txt"
}

_detect_binary() {
	os="$(uname)"
	case "$os" in
		Linux) echo "k0s" ;;
		*) echo "Unsupported operating system: $os" 1>&2; return 1 ;;
	esac
	unset os
}

_detect_arch() {
	arch="$(uname -m)"
	case "$arch" in
		amd64|x86_64) echo "amd64" ;;
		arm64|aarch64) echo "arm64" ;;
		armv7l|armv8l|arm) echo "arm" ;;
		*) echo "Unsupported processor architecture: $arch" 1>&2; return 1 ;;
	esac
	unset arch
}

_download_url() {
	echo "https://github.com/k0sproject/k0s/releases/download/$K0S_VERSION/$k0sBinary-$K0S_VERSION-$K0S_ARCH"
}

main() {
	: "${CURL:=curl}"
	: "${WGET:=wget}"
	: "${K0S_VERSION:=$(_k0s_latest)}"
	: "${K0S_INSTALL_PATH:=/usr/local/bin}"
	[ -n "${K0S_ARCH:-}" ] || K0S_ARCH=$(_detect_arch)

	k0sBinary=$(_detect_binary)
	k0sDownloadUrl="$(_download_url)"

	mkdir -p -- "$K0S_INSTALL_PATH"

	echo "Downloading k0s from URL: $k0sDownloadUrl"

	_fetch "$k0sDownloadUrl" >"$K0S_INSTALL_PATH/$k0sBinary"
	chmod 755 -- "$K0S_INSTALL_PATH/$k0sBinary"

	echo "k0s is now executable in $K0S_INSTALL_PATH"
	echo "You can use it to complete the installation of k0s on this node, "
	echo "see https://docs.k0sproject.io/stable/install/ for more information."
}

main