#!/usr/bin/env bash
#shellcheck disable=SC2164

# this script will uninstall netdata

# Variables needed by script:
#  - PATH
#  - CFLAGS
#  - NETDATA_CONFIGURE_OPTIONS
#  - REINSTALL_COMMAND
#  - NETDATA_TARBALL_URL
#  - NETDATA_TARBALL_CHECKSUM_URL
#  - NETDATA_TARBALL_CHECKSUM


# Usually stored in /etc/netdata/.environment
: "${ENVIRONMENT_FILE:=THIS_SHOULD_BE_REPLACED_BY_INSTALLER_SCRIPT}"

# shellcheck source=/dev/null
source "${ENVIRONMENT_FILE}" || exit 1

if [ "${INSTALL_UID}" != "$(id -u)" ]; then
	echo >&2 "You are running this script as user with uid $(id -u). We recommend to run this script as root (user with uid 0)"
	exit 1
fi

# signal netdata to start saving its database
# this is handy if your database is big
pids=$(pidof netdata)
do_not_start=
if [ -n "${pids}" ]; then
	#shellcheck disable=SC2086
	kill -USR1 ${pids}
else
	# netdata is currently not running, so do not start it after updating
	do_not_start="--dont-start-it"
fi

tmp=
if [ -t 2 ]; then
	# we are running on a terminal
	# open fd 3 and send it to stderr
	exec 3>&2
else
	# we are headless
	# create a temporary file for the log
	tmp=$(mktemp /tmp/netdata-updater.log.XXXXXX)
	# open fd 3 and send it to tmp
	exec 3>"${tmp}"
fi

info() {
	echo >&3 "$(date) : INFO: " "${@}"
}

error() {
	echo >&3 "$(date) : ERROR: " "${@}"
}

# this is what we will do if it fails (head-less only)
failed() {
	error "FAILED TO UPDATE NETDATA : ${1}"

	if [ -n "${tmp}" ]; then
		cat >&2 "${tmp}"
		rm "${tmp}"
	fi
	exit 1
}

update() {
	[ -z "${tmp}" ] && info "Running on a terminal - (this script also supports running headless from crontab)"

	# Check if tmp is mounted as noexec
	if grep -Eq '^[^ ]+ /tmp [^ ]+ ([^ ]*,)?noexec[, ]' /proc/mounts; then
		pattern="/opt/netdata-updater-XXXXXX"
	else
		pattern="/tmp/netdata-updater-XXXXXX"
	fi

	dir=$(mktemp -d "$pattern")

	cd "$dir"

	wget "${NETDATA_TARBALL_CHECKSUM_URL}" -O sha256sum.txt >&3 2>&3
	if grep "${NETDATA_TARBALL_CHECKSUM}" sha256sum.txt >&3 2>&3; then
		info "Newest version is already installed"
		exit 0
	fi

	wget "${NETDATA_TARBALL_URL}" -O netdata-latest.tar.gz >&3 2>&3
	if ! grep netdata-latest.tar.gz sha256sum.txt | sha256sum --check - >&3 2>&3; then
		failed "Tarball checksum validation failed. Stopping netdata upgrade and leaving tarball in ${dir}"
	fi
	NEW_CHECKSUM="$(sha256sum netdata-latest.tar.gz 2>/dev/null| cut -d' ' -f1)"
	tar -xf netdata-latest.tar.gz >&3 2>&3
	rm netdata-latest.tar.gz >&3 2>&3
	cd netdata-*

	info "Re-installing netdata..."
	${REINSTALL_COMMAND} --dont-wait ${do_not_start} >&3 2>&3 || failed "FAILED TO COMPILE/INSTALL NETDATA"
	sed -i '/NETDATA_TARBALL/d' "${ENVIRONMENT_FILE}"
	cat <<EOF >>"${ENVIRONMENT_FILE}"
NETDATA_TARBALL_URL="$NETDATA_TARBALL_URL"
NETDATA_TARBALL_CHECKSUM_URL="$NETDATA_TARBALL_CHECKSUM_URL"
NETDATA_TARBALL_CHECKSUM="$NEW_CHECKSUM"
EOF

	rm -rf "${dir}" >&3 2>&3
	[ -n "${tmp}" ] && rm "${tmp}" && tmp=
	return 0
}

# the installer updates this script - so we run and exit in a single line
update && exit 0