#! /usr/bin/env sh

while [ $# -gt 0 ]; do
	case "$1" in
		--dry-run)
			DRY_RUN=1
			shift
		;;
		--*)
			echo "Illegal Operation"
		;;
	esac
done

is_dry_run() {
	if [ -z "$DRY_RUN" ]; then
		return 1
	else 
		return 0
	fi
}

command_exists() {
	command -v "$@" > /dev/null 2>&1
}

to_lower() {
	echo "$@" | tr '[:upper:]' '[:lower:]'
}


check_distro() {
	distro=""
	if [ -r /etc/os-release ]; then
		distro="$(. /etc/os-release && echo "$ID")"
	fi
	echo "$distro"
}

detect_debian_version() {
	version=""
	vers_num="$(sed 's/\/.*//' /etc/debian_version | sed 's/\..*//')"
	case "$vers_num" in
		12 | trixie)
			version="bookworm"
		;;
		11)
			version="bullseye"
		;;
		10)
			version="buster"
		;;
		9)
			version="stretch"
		;;
		8)
			version="jessie"
		;;
		esac
		echo "$version"
}

exec_command() {
	uid="$(id -u 2>/dev/null || true)"
	sh_c="sh -c"
	if [ "$uid" != 0 ]; then
		if command_exists sudo; then
			sh_c="sudo -E sh -c"
		elif command_exists su; then
			sh_c="su -c"
		else
			cat >&2 <<-'EOF'
			Error: no method for command elevation found, but thats needed for this setup script
			EOF
			exit 1
		fi
	fi
	if is_dry_run; then
		sh_c="echo"
	fi
	echo $sh_c
}

install_docker_apt() {
	pre_reqs="apt-transport-https ca-certificates curl"
	rem_pkgs="docker.io docker-doc docker-compose podman-docker containerd runc"
	inst_pkgs="docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin"
	apt_repo="deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] $download_url/linux/$distro $version $channel"
	(
		if ! is_dry_run; then
			set -x
		fi
		$sh_c 'apt-get update -qq >/dev/null'
		$sh_c "DEBIAN_FRONTEND=noninteractive apt-get remove -y -qq $rem_pkgs >/dev/null"
		$sh_c "DEBIAN_FRONTEND=noninteractive apt-get install -y -qq $pre_reqs >/dev/null"
		$sh_c 'install -m 0755 -d /etc/apt/keyrings'
		$sh_c "curl -fsSL \"$download_url/linux/$distro/gpg\" -o /etc/apt/keyrings/docker.asc"
		$sh_c "chmod a+r /etc/apt/keyrings/docker.asc"
		$sh_c "echo \"$apt_repo\" > /etc/apt/sources.list.d/docker.list"
		$sh_c 'apt-get update -qq >/dev/null'
		$sh_c "DEBIAN_FRONTEND=noninteractive apt-get install -y -qq $inst_pkgs >/dev/null"
	)
}

install_acl_apt() {
	inst_pkgs="acl"
	(
		if ! is_dry_run; then
			set -x
		fi
		$sh_c 'apt-get update -qq >/dev/null'
		$sh_c "DEBIAN_FRONTEND=noninteractive apt-get install -y -qq $inst_pkgs >/dev/null"
	)
}

group_add_docker() {
	sh_c="$( exec_command )"
	if [ -f /sbin/usermod ]; then
		$sh_c "usermod -aG docker $(id -un)"
	else
		cat >&2 <<-'EOF'
		Error: no command for group editing found
		EOF
		exit 1
	fi
}

start_docker_boot() {
	sh_c="$( exec_command )"
	if command_exists systemctl; then
		$sh_c 'systemctl enable --now docker.service'
	else 
		cat >&2 <<-'EOF'
		Error: no supported init system found
		EOF
		exit 1
	fi
}

mk_docker_dir() {
	docker_root="/opt"
	sh_c="$( exec_command )"
	if ! command_exists setfacl; then
		install_acl_apt
	fi
	(
		if ! is_dry_run; then
			set -x
		fi
		$sh_c "mkdir -p $docker_root/docker/ $docker_root/docker/compose $docker_root/docker/data"
		$sh_c "chgrp -R docker $docker_root/docker"
		$sh_c "chmod -R g+s $docker_root/docker"
		$sh_c "setfacl -R -m u::rwx,g::rwx $docker_root/docker"
		$sh_c "setfacl -R -d --set u::rwx,g::rwx,o::r-x $docker_root/docker"
	)
}

install_docker() {
	sh_c="$( exec_command )"
	distro="$( check_distro )"
	version=""
	channel="stable"
	download_url="https://download.docker.com"
	case "$distro" in
		debian)
			echo " Debian detected"
			version="$( detect_debian_version )"
			install_docker_apt
			echo "󰡨 Docker successfully installed"
		;;
		*)
			echo "Sorry currently only debian is supported"
	esac
}

read -p "Install docker? (y/N) " if_docker_group
case $(to_lower $if_docker_group) in
	"yes" | "y" | "yeah" | 1)
		install docker
	;;
esac
read -p "Add $(id -un) to docker group? (y/N) " if_docker_group
case $(to_lower $if_docker_group) in
	"yes" | "y" | "yeah" | 1)
		group_add_docker
	;;
esac
read -p "Start Docker at boot? (y/N)" if_start_docker_boot
case $(to_lower $if_start_docker_boot) in
	"yes" | "y" | "yeah" | 1)
		start_docker_boot
	;;
esac
read -p "Create Docker dir with ACL permissions? (y/N)" if_mk_docker_dir
case $(to_lower $if_mk_docker_dir) in
	"yes" | "y" | "yeah" | 1)
		mk_docker_dir
	;;
esac