# Author: Martin Matusiak <numerodix@gmail.com>
# Licensed under the GNU Public License, version 3
#
# <desc> Detect OS (platform and version) of local machine </desc>
#
# <usage>
# source this file in bash, then run `osdetect`
# </usage>


_concat() {
	local s="$1";shift;
	while [ "$1" ]; do
		s="$s $1"; shift
	done
	echo "$s" | sed "s|^[ \t]*||g" | sed "s|[ \t]*$||g"
}

_glob() {
	local file=
	local glob=
	local lst=
	while [ -z "$file" ] && [ "$1" ]; do
		glob="$1";shift;
		lst=$(ls $glob 2>/dev/null | grep -v /etc/lsb-release)
		if [ "$lst" ]; then
			file=$(echo "$lst" | head -n1)
		fi
	done
	echo "$file"
}

osdetect() {
	# ref: http://linuxmafia.com/faq/Admin/release-files.html

	local os=
	local release=
	local machine=
	if ! which uname &>/dev/null; then
		echo -e "${cred}No uname on system${creset}" >&2
		os="N/A"
	else
		os=$(uname -s)
		release=$(uname -r)
		machine=$(uname -m)
	fi
	if [ "$os" = "SunOS" ]; then
		os="Solaris"
		machine=$(uname -p)
	fi
	local platform="$(_concat "$os" "$release" "$machine")"

	# prefer lsb_release
	if which lsb_release &>/dev/null; then
		local id="$(_concat "$(lsb_release -i | sed "s|.*:||g")")"
		local rel="$(_concat "$(lsb_release -r | sed "s|.*:||g")")"
		local code="$(_concat "$(lsb_release -c | sed "s|.*:||g")")"
	elif [ -f /etc/lsb-release ]; then
		local id="$(_concat "$(grep DISTRIB_ID /etc/lsb-release | sed "s|.*=||g")")"
		local rel="$(_concat "$(grep DISTRIB_RELEASE /etc/lsb-release | sed "s|.*=||g")")"
		local code="$(_concat "$(grep DISTRIB_CODENAME /etc/lsb-release | sed "s|.*=||g")")"

	# find a file or another
	else
		local vfile=$(_glob "/etc/*-rel*" "/etc/*_ver*" "/etc/*-version")
		[ "$vfile" ] && local id=$(cat "$vfile")

		# distro specific
		[ "$vfile" = /etc/debian_version ] && [ "$id" ] && id="Debian $id"
	fi

	[ "$id" = "n/a" ] && id=
	[ "$rel" = "n/a" ] && rel=
	[ "$code" = "n/a" ] && code=

	local version="$(_concat "$id" "$rel" "$code")"
	[ ! -z "$version" ] && version=" ~ ${cyellow}$version${creset}"

	echo -e "Platform: ${ccyan}${platform}${creset}${version}"
}