#!/usr/bin/env bash

# version - MUST be exactly 7 characters!
UPDATE="2025v01"

#----------------------------------------------------------------------
# The intention of this script is that it should be able to be run
# multiple times WITHOUT doing any harm. If you propose changes, please
# make sure you test the script in both a "green fields" system AND on
# a working system where docker, docker-compose and IOTstack are already
# installed.
#----------------------------------------------------------------------

# overuse of sudo is a very common problem among new IOTstack users
[ "$EUID" -eq 0 ] && echo "This script should NOT be run using sudo" && exit 1

# where is this script is running?
WHERE=$(dirname "$(realpath "$0")")

# if this script looks like it is running in a clone (or unzip) of
# IOTstack then base operations there, otherwise default to the
# standard location of ~/IOTstack. Either way, permit override by
# prepending IOTSTACK=path to the script call.
[ -d "$WHERE/.templates" -a -d "$WHERE/docs" ] && PROJECT="$WHERE" || PROJECT="$HOME/IOTstack"
IOTSTACK=${IOTSTACK:-"$PROJECT"}

# derived path(s) - note that the menu knows about most of these so
# they can't just be changed without a lot of care.
IOTSTACK_ENV="$IOTSTACK/.env"
IOTSTACK_MENU_REQUIREMENTS="$IOTSTACK/requirements-menu.txt"
IOTSTACK_MENU_VENV_DIR="$IOTSTACK/.virtualenv-menu"
IOTSTACK_INSTALLER_HINT="$IOTSTACK/.new_install"

# git cloning options which can be overridden
# (needs special handling for the null case)
if [[ ! -v GIT_CLONE_OPTIONS ]] ; then
	GIT_CLONE_OPTIONS="--filter=tree:0"
fi

# the expected installation location of docker-compose-plugin is
COMPOSE_PLUGIN_PATH="/usr/libexec/docker/cli-plugins/docker-compose"

# the default location of a symlink in the PATH pointing to the above is
COMPOSE_SYMLINK_PATH="/usr/local/bin/docker-compose"

# add these to /boot/cmdline.txt (if it exists)
CMDLINE_OPTIONS="cgroup_memory=1 cgroup_enable=memory"

# dependencies installed via apt
APT_DEPENDENCIES="curl git jq pwgen python3-pip python3-dev python3-virtualenv uuid-runtime whiptail"

# minimum version requirements
DOCKER_VERSION_MINIMUM="24"
COMPOSE_VERSION_MINIMUM="2.20"
PYTHON_VERSION_MINIMUM="3.9"

# best-practice for group membership
DESIRED_GROUPS="docker bluetooth dialout"

# what to do at script completion (reboot takes precedence)
REBOOT_REQUIRED=false
LOGOUT_REQUIRED=false

#----------------------------------------------------------------------
# versioning functions
#----------------------------------------------------------------------

# version_json()
#
# Arguments
#    $1 exit code
# Returns:
#    JSON string with version, commit ID and exit code
# Note:
#    If $0 is not under Git control (eg a zip download of IOTstack) then
#    the commit field will be an empty string.
#
version_json() {
	echo "{\"version\": \"${UPDATE}\", \"commit\": \"$(git log -n 1 --pretty=format:%H -- "${0}" 2>/dev/null)\", \"exitCode\": ${1}}"
}


# should_run_installer()
#
# Arguments
#    none
# Returns
#    "false" or "true"
# Theory:
#    Under normal conditions, running install.sh will result in the
#    hint file (.new_install) having the JSON string returned by
#    version_json(), which contains the current version number and
#    current commit ID of install.sh, plus an exit code of zero.
#
#    If IOTstack is downloaded as a zip rather than a clone, the commit
#    ID will be null but, other than placing a heavier reliance on the
#    version number **changing**, that does not actually matter.
#
#    Historically, .new_install has evolved through three generations:
#
#    Gen 1: A touch file where its mere existence signalled that
#           install.sh had been run.
#    Gen 2: A file recording the exit code of the most-recent run. The
#           menu has never actually taken advantage of this.
#    Gen 3: The JSON string returned by version_json().
#
#    This function will return "true" if any of the following is true:
#
#    1. install.sh has never been run to perform an installation (or
#       PiBuilder has not faked things on this script's behalf). In
#       other words, this is the situation where .new_install is absent.
#    2. The last run of install.sh either produced a Gen 2 file
#       (irrespective of the exit code value) or a Gen 3 file with a
#       non-zero exit code.
#    3. Either/both the embedded version number or commit ID have
#       changed as a result of an update.
#
should_run_installer() {
	# does the hint file exist and is it non-empty?
	if [ -s "${IOTSTACK_INSTALLER_HINT}" ] ; then
		# yes! compare content
		if [ "$(cat "${IOTSTACK_INSTALLER_HINT}")" = "$(version_json 0)" ] ; then
			echo "false"
			return
		fi
	fi
	echo "true"
}


#----------------------------------------------------------------------
# arguments
#----------------------------------------------------------------------

# any arguments passed on command-line?
if [ $# -gt 0 ] ; then

	# vector on command verb
	case "${1}" in

		"version" )
			echo "$(version_json 0)"
		;;

		"should_run_installer" )
			echo "$(should_run_installer)"
		;;

		*)
			cat <<-HELP

				Usage:
				  ${SCRIPT} (with no arguments runs the installer)
				  ${SCRIPT} version - returns JSON version string
				  ${SCRIPT} should_run_installer - returns "false" or "true"
				  ${SCRIPT} help - displays this menu

			HELP
		;;

	esac

	# normal exit (ie does not fall through to the menu)
	exit 0

fi


#----------------------------------------------------------------------
# main installer code
#----------------------------------------------------------------------

echo "                                         "
echo "  _____ ____ _______  _  installer  _    "
echo " |_   _/ __ \\__   __|| |  $UPDATE  | |  "
echo "   | || |  | | | |___| |_ __ _  ___| | __"
echo "   | || |  | | | / __| __/ _\` |/ __| |/ /"
echo "  _| || |__| | | \\__ \\ || (_| | (__|   < "
echo " |_____\\____/  |_|___/\\__\\__,_|\\___|_|\\_\\"
echo "                                         "
echo "                                         "

#----------------------------------------------------------------------
#						Check script dependencies
#----------------------------------------------------------------------

echo -e -n "\nChecking operating-system environment - "
# This script assumes apt and dpkg are available. That's more-or-less
# the same as saying Debian oe Debian-derived. If apt and/or dpkg are
# missing then there's not much that can be done.
if [ -z $(which apt) -o -z $(which dpkg) ] ; then
	echo "fail"
	unset ID
	[ -f "/etc/os-release" ] && eval $(grep "^ID=" /etc/os-release)
	if [ "$ID" = "debian" ] ; then
		echo "This system looks like it is based on Debian but seems to be missing"
		echo "some key utilities (apt and/or dpkg). That suggests something is wrong."
		echo "This script can't proceed until those issues are resolved."
	else
		echo "Some key utilities that are needed by this script seem to be missing"
		echo "from this system. Both the Advanced Package Tool (apt) and the Debian"
		echo "Package Manager (dpkg) are core components of Debian and Debian-derived"
		echo "distributions like Raspberry Pi OS (aka Raspbian). It looks like you"
		echo "might be trying to install IOTstack on a system which isn't based on"
		echo "Debian. IOTstack has only ever been tested on Debian-based distributions"
		echo "and is not qualified for other Linux or Unix distributions. This script"
		echo "can't proceed."
	fi
	# direct exit - not via handle_exit()
	exit 1
else
	echo "pass"
fi


#----------------------------------------------------------------------
#					script memory (exit conditions)
#----------------------------------------------------------------------

function handle_exit() {

	# record the exit condition (if possible)
	[ -d "$IOTSTACK" ] && echo "$(version_json $1)" >"$IOTSTACK_INSTALLER_HINT"

	# inform the user
	echo -n "install.sh completed"

	# advise if should be re-run
	[ $1 -ne 0 ] && echo -n " - but should be re-run"

	# reboot takes precedence over logout
	if [ "$REBOOT_REQUIRED" = "true" ] ; then
		echo " - a reboot is required."
		sleep 2
		sudo reboot
	elif [ "$LOGOUT_REQUIRED" = "true" ] ; then
		echo " - a logout is required."
		sleep 2
		# iterate ancestor processes
		for ANCESTOR in $(ps -o ppid=) ; do
			# find first process belonging to current user
			if [ "$(ps -p $ANCESTOR -o user=)" = "$USER" ] ; then
				# kill it
				kill -HUP $ANCESTOR
			fi
		done
		# should not reach this
		sleep 2
	fi

	# exit as instructed
	echo ""
	exit $1

}


#----------------------------------------------------------------------
#				IOTstack dependencies installed via apt
#----------------------------------------------------------------------

echo -e "\nUpdating Advanced Package Tool (apt) caches"
sudo apt update

echo -e "\nInstalling/updating IOTstack dependencies"
sudo apt install -y $APT_DEPENDENCIES


#----------------------------------------------------------------------
#						docker + compose installation
#----------------------------------------------------------------------

# is docker installed?
if [ -z $(which docker) ] ; then
	# no! use the convenience script
	echo -e "\nInstalling docker and docker-compose-plugin using the 'convenience script'"
	echo "from https://get.docker.com ..."
	curl -fsSL https://get.docker.com | sudo sh
	if [ $? -eq 0 ] ; then
		echo -e "\nInstallation of docker and docker-compose-plugin completed normally."
		REBOOT_REQUIRED=true
	else
		echo -e "\nThe 'convenience script' returned an error. Unable to proceed."
		handle_exit 1
	fi
else
	echo -e -n "\nDocker is already installed - checking your version - "
	DOCKER_VERSION_INSTALLED="$(docker version -f "{{.Server.Version}}")"
	if dpkg --compare-versions "$DOCKER_VERSION_MINIMUM" "gt" "$DOCKER_VERSION_INSTALLED" ; then
		echo "fail"
		echo "You have an obsolete version of Docker installed:"
		echo "      Minimum version required: $DOCKER_VERSION_MINIMUM"
		echo "   Version currently installed: $DOCKER_VERSION_INSTALLED"
		echo "Try updating your system by running:"
		echo "   \$ sudo apt update && sudo apt upgrade -y"
		echo "   \$ docker version -f {{.Server.Version}}"
		echo "If the version number changes, try re-running this script. If the"
		echo "version number does not change, you may need to uninstall both"
		echo "docker and docker-compose. If any containers are running, stop"
		echo "them, then run:"
		echo "   \$ sudo systemctl stop docker.service"
		echo "   \$ sudo systemctl disable docker.service"
		echo "   \$ sudo apt -y purge docker-ce docker-ce-cli containerd.io docker-compose"
		echo "   \$ sudo apt -y autoremove"
		echo "   \$ sudo reboot"
		echo "and then re-run this script after the reboot."
		handle_exit 1
	else
		echo "pass"
	fi
fi


#----------------------------------------------------------------------
#							group memberships
#----------------------------------------------------------------------

function should_add_user_to_group()
{
	# sense group does not exist
	grep -q "^$1:" /etc/group || return 1
	# sense group exists and user is already a member
	groups | grep -q "\b$1\b" && return 1
	# group exists, user should be added
	return 0
}

# check group membership
echo -e -n "\nChecking group memberships"
for GROUP in $DESIRED_GROUPS ; do
	echo -n " - $GROUP "
	if should_add_user_to_group $GROUP ; then
		echo -n "adding $USER"
		sudo /usr/sbin/usermod -G $GROUP -a $USER
		LOGOUT_REQUIRED=true
	else
		echo -n "pass"
	fi
done
echo ""

#----------------------------------------------------------------------
#					docker-compose setup/verification
#----------------------------------------------------------------------

# Correct installation of docker-compose is defined as the result of
# `which docker-compose` (typically $COMPOSE_SYMLINK_PATH) being a
# symlink pointing to the expected location of docker-compose-plugin as
# it is installed by the convenience script ($COMPOSE_PLUGIN_PATH).
# Alternatively, if `which docker-compose` returns null but the plugin
# is in the expected location, the necessary symlink can be created by
# this script and then docker-compose will be installed "correctly".

function is_python_script() {
	[ $(file -b "$1" | grep -c "^Python script") -gt 0 ] && return 0
	return 1
}

# presume docker-compose not installed correctly
COMPOSE_INSTALLED_CORRECTLY=false

# search for docker-compose in the PATH
COMPOSE_CMD_PATH=$(which docker-compose)

# is docker-compose in the PATH?
echo -e -n "\nChecking whether docker-compose is installed correctly - "
if [ -n "$COMPOSE_CMD_PATH" ] ; then
	# yes! is it a symlink and does the symlink point to a file?
	if [ -L "$COMPOSE_CMD_PATH" -a -f "$COMPOSE_CMD_PATH" ] ; then
		# yes! fetch the inode of what the link points to
		COMPOSE_CMD_INODE=$(stat -c "%i" -L "$COMPOSE_CMD_PATH")
		# does the plugin exist at the expected path?
		if [ -f "$COMPOSE_PLUGIN_PATH" ] ; then
			# yes! fetch the plugin's inode
			COMPOSE_PLUGIN_INODE=$(stat -c "%i" "$COMPOSE_PLUGIN_PATH")
			# are the inodes the same?
			if [ $COMPOSE_CMD_INODE -eq $COMPOSE_PLUGIN_INODE ] ; then
				# yes! thus docker-compose is installed correctly
				COMPOSE_INSTALLED_CORRECTLY=true
			fi
		fi
	fi
else
	# no! does the plugin exist at the expected location?
	if [ -f "$COMPOSE_PLUGIN_PATH" ] ; then
		# yes! so, no command, but plugin present. Fix with symlink
		sudo ln -s "$COMPOSE_PLUGIN_PATH" "$COMPOSE_SYMLINK_PATH"
		# and now compose is installed correctly
		COMPOSE_INSTALLED_CORRECTLY=true
	else
		echo "fail"
		echo "Your system has docker installed but doesn't seem to have either"
		echo "docker-compose or docker-compose-plugin. Try running:"
		echo "   \$ sudo apt install -y docker-compose-plugin"
		echo "and then try re-running this script."
		handle_exit 1
	fi
fi

# is docker-compose installed correctly?
if [ "$COMPOSE_INSTALLED_CORRECTLY" = "true" ] ; then
	echo "pass"
	echo -e -n "\nChecking your version of docker-compose - "
	COMPOSE_VERSION_INSTALLED="$(docker-compose version --short)"
	if dpkg --compare-versions "$COMPOSE_VERSION_MINIMUM" "gt" "$COMPOSE_VERSION_INSTALLED" ; then
		echo "fail"
		echo "You have an obsolete version of docker-compose installed:"
		echo "      Minimum version required: $COMPOSE_VERSION_MINIMUM"
		echo "   Version currently installed: $COMPOSE_VERSION_INSTALLED"
		echo "Try updating your system by running:"
		echo "   \$ sudo apt update && sudo apt upgrade -y"
		echo "and then try re-running this script."
		handle_exit 1
	else
		echo "pass"
	fi
else
	echo "fail"
	echo "docker-compose is not installed correctly. The most common reason is"
	echo "having installed docker and docker-compose without using the official"
	echo "'convenience script'. You may be able to solve this problem by running"
	if is_python_script "$COMPOSE_CMD_PATH" ; then
		echo "   \$ export PIP_BREAK_SYSTEM_PACKAGES=1"
		echo "   \$ pip3 uninstall -y docker-compose"
		echo "   \$ sudo pip3 uninstall -y docker-compose"
		echo "   (ignore any errors from those commands)"
	else
		echo "   \$ sudo apt purge -y docker-compose"
	fi
	echo "and then try re-running this script."
	handle_exit 1
fi


#----------------------------------------------------------------------
#							Clone IOTstack repo
#----------------------------------------------------------------------

# does the IOTstack folder already exist?
if [ ! -d "$IOTSTACK" ] ; then
	# no! clone from GitHub
	if [ -n "$GIT_CLONE_OPTIONS" ] ; then
		echo -e "\nCloning the IOTstack repository from GitHub using options $GIT_CLONE_OPTIONS"
		git clone "$GIT_CLONE_OPTIONS" https://github.com/SensorsIot/IOTstack.git "$IOTSTACK"
	else
		echo -e "\nCloning the full IOTstack repository from GitHub"
		git clone https://github.com/SensorsIot/IOTstack.git "$IOTSTACK"
	fi
	if [ $? -eq 0 -a -d "$IOTSTACK" ] ; then
		echo "IOTstack cloned successfully into $IOTSTACK"
	else
		echo "Unable to clone IOTstack (likely a git or network error)"
		handle_exit 1
	fi
else
	echo -e "\n$IOTSTACK already exists - no need to clone from GitHub"
fi

# ensure backups and services directories exist and are owned by $USER
# https://github.com/SensorsIot/IOTstack/issues/651#issuecomment-2525347511
mkdir -p "$IOTSTACK/backups" "$IOTSTACK/services"
sudo chown -R "$USER:$USER" "$IOTSTACK/backups" "$IOTSTACK/services"
# but, if the influxdb backup dir already exists, put it back to root
[ -d "$IOTSTACK/backups/influxdb" ] && sudo chown -R "root:root" "$IOTSTACK/backups/influxdb"

# initialise docker-compose global environment file with system timezone
# see https://git.gsi.de/chef/cookbooks/sys/-/issues/54
if [ ! -f "$IOTSTACK_ENV" ] || [ $(grep -c "^TZ=" "$IOTSTACK_ENV") -eq 0 ] ; then
	echo "TZ=$(timedatectl show --value --property=Timezone)" >>"$IOTSTACK_ENV"
fi

#----------------------------------------------------------------------
#								Python support
#----------------------------------------------------------------------

# make sure "python" invokes "python3"
PYTHON_INVOKES=$(update-alternatives --list python 2>/dev/null)
PYTHON3_PATH=$(which python3)
if [ "$PYTHON_INVOKES" != "$PYTHON3_PATH" ] ; then
	echo -e "\nMaking python3 the default"
	sudo update-alternatives --install /usr/bin/python python "$PYTHON3_PATH" 1
fi

echo -e -n "\nChecking your version of Python - "
PYTHON_VERSION_INSTALLED="$(python --version)"
PYTHON_VERSION_INSTALLED="${PYTHON_VERSION_INSTALLED#*Python }"
if dpkg --compare-versions "$PYTHON_VERSION_MINIMUM" "gt" "$PYTHON_VERSION_INSTALLED" ; then
	echo "fail"
	echo "You have an obsolete version of python installed:"
	echo "      Minimum version required: $PYTHON_VERSION_MINIMUM"
	echo "   Version currently installed: $PYTHON_VERSION_INSTALLED"
	echo "Try updating your system by running:"
	echo "   \$ sudo apt update && sudo apt upgrade -y"
	echo "   \$ python --version"
	echo "If the version number changes, try re-running this script. If not, you"
	echo "may need to reinstall python3-pip, python3-dev and python3-virtualenv."
	handle_exit 1
else
	echo "pass"
fi

# implement menu requirements
if [ -e "$IOTSTACK_MENU_REQUIREMENTS" ] ; then
	echo -e "\nChecking and updating IOTstack dependencies (pip)" 
	echo "Note: pip3 installs bypass externally-managed environment check"
	PIP_BREAK_SYSTEM_PACKAGES=1 pip3 install -U -r "$IOTSTACK_MENU_REQUIREMENTS"
fi

# trigger re-creation of venv on next menu launch. Strictly speaking,
# sudo is not required for this but it protects against accidental prior
# use of sudo when the venv was created
sudo rm -rf "$IOTSTACK_MENU_VENV_DIR"


#----------------------------------------------------------------------
#						Raspberry Pi boot options
#----------------------------------------------------------------------

# set cmdline options (if possible - Raspberry Pi dependency)
TARGET="/boot/firmware/cmdline.txt"
[ -e "$TARGET" ] || TARGET="/boot/cmdline.txt"
if [ -e "$TARGET" ] ; then
	echo -e -n "\nChecking Raspberry Pi boot-time options - "
	unset APPEND
	for OPTION in $CMDLINE_OPTIONS ; do
		if [ $(grep -c "$OPTION" "$TARGET") -eq 0 ] ; then
			APPEND="$APPEND $OPTION"
		fi
	done
	if [ -n "$APPEND" ] ; then
		echo "appending$APPEND"
		sudo sed -i.bak "s/$/$APPEND/" "$TARGET"
		REBOOT_REQUIRED=true
	else
		echo "no modifications needed"
	fi
fi


#----------------------------------------------------------------------
#							normal exit
#----------------------------------------------------------------------

handle_exit 0