#!/bin/sh -e

tag_file="$(mktemp)"
trap 'rm "${tag_file}"' EXIT

add_tag() {
	for tag in "$@"; do
		if ! has_tags "$tag"; then
			echo "Adding detected tag: $tag"
			echo "${tag}" >> "${tag_file}"
		fi
	done
}

has_tags() {
	for req in "$@"; do
		printf "Checking for tag: $req... "
		local detected=0
		while IFS= read -r line; do
			if [ "$line" = "$req" ]; then
				echo "yes"
				detected=1
				break
			fi
		done < "$tag_file"
		if [ "$detected" -eq 0 ]; then
			echo "no"
			return 1
		fi
	done
	return 0
}

has_binary() {
	printf "Checking for binary: $1... "
	if ! command -v "$1" >/dev/null 2>&1; then
		echo "no"
		return 1
	fi
	echo "yes"
	return 0
}

# arch linux

if [ -f /etc/arch-release ]; then
	add_tag os:arch
	add_tag os_like:archlinux
fi

# os-release

if [ -f /etc/os-release ]; then
	(
		source /etc/os-release
		add_tag "os:${ID}"
		if [ ! -z "${ID_LIKE}" ]; then
			add_tag "os_like:${ID_LIKE}"
		fi
		if [ ! -z "${VERSION_ID}" ]; then
			add_tag "version:${VERSION_ID}"
		fi
		if [ ! -z "${VERSION_CODENAME}" ]; then
			add_tag "version:${VERSION_CODENAME}"
		fi
		if [ ! -z "${UBUNTU_CODENAME}" ]; then
			add_tag "version:${UBUNTU_CODENAME}"
		fi
	)
fi

# package manager detection

for pm in \
	pacaur \
	pacman \
	pip \
	npm \
	yaourt \
	yarn \
	yay \
	; do
	if has_binary "$pm"; then
		add_tag "pm:$pm"
	fi
done

# graphics UI detection
# basically just checks if an X server is running on the machine and if yes, we just assume it's a desktop, not a server
# grep will be always returned as a process with Xorg in the command line, so assume there must be a second process for this to succeed
if [ $(ps aux | grep Xorg | wc -l) -gt 1 ]; then
	add_tag "xorg_running" "desktop"
fi