#!/usr/bin/env bash

set -o errexit           # treat errors as fatal
set -o nounset           # treat unset variables as an error
set -o pipefail          # treat errors in pipes as fatal
shopt -s inherit_errexit # inherit errexit

# make it possible to disable the inotify watcher process
ENABLE_RESCAN_ON_FILESYSTEM_CHANGE="${ENABLE_RESCAN_ON_FILESYSTEM_CHANGE:="false"}"
ENABLE_SCHEDULED_RESCAN="${ENABLE_SCHEDULED_RESCAN:="false"}"
ENABLE_SCHEDULED_UPDATE_SWITCH_TITLEDB="${ENABLE_SCHEDULED_UPDATE_SWITCH_TITLEDB:="false"}"

# Set INIT_DEBUG to false if not set by docker env
# (this env var is currently undocumented and usually just needed for development purposes)
INIT_DEBUG="${INIT_DEBUG:="false"}"

# print debug log output if enabled
debug_log() {
	if [[ ${INIT_DEBUG} == "true" ]]; then
		echo "DEBUG:    [RomM][init][$(date +"%Y-%m-%d %T")]" "${@}" || true
	fi
}

info_log() {
	echo "INFO:     [RomM][init][$(date +"%Y-%m-%d %T")]" "${@}" || true
}

warn_log() {
	echo "WARNING:  [RomM][init][$(date +"%Y-%m-%d %T")]" "${@}" || true
}

error_log() {
	echo "ERROR:    [RomM][init][$(date +"%Y-%m-%d %T")]" "${@}" || true
	exit 1
}

wait_for_gunicorn_socket() {
	info_debug "Waiting for gunicorn socket file..."
	while [[ ! -S /tmp/gunicorn.sock ]]; do
		sleep 1
	done
	info_debug "Gunicorn socket file found"
}

# function that runs or main process and creates a corresponding PID file,
start_bin_gunicorn() {
	# cleanup potentially leftover socket
	rm /tmp/gunicorn.sock -f

	# commands to start our main application and store its PID to check for crashes
	info_log "Starting backend"

	# TODO: Remove support for GUNICORN_WORKERS in future version.
	if [[ -n ${GUNICORN_WORKERS-} ]]; then
		warn_log "GUNICORN_WORKERS variable is deprecated, use WEB_CONCURRENCY instead"
		: "${WEB_CONCURRENCY:=${GUNICORN_WORKERS}}"
	fi

	gunicorn \
		--access-logfile - \
		--error-logfile - \
		--worker-class uvicorn.workers.UvicornWorker \
		--bind=0.0.0.0:5000 \
		--bind=unix:/tmp/gunicorn.sock \
		--pid=/tmp/gunicorn.pid \
		--forwarded-allow-ips="*" \
		--workers "${WEB_CONCURRENCY:-2}" \
		main:app &
}

# Commands to start nginx (handling PID creation internally)
start_bin_nginx() {
	wait_for_gunicorn_socket

	info_log "Starting internal nginx"
	if [[ ${EUID} -ne 0 ]]; then
		nginx
	else
		# if container runs as root, drop permissions
		nginx -g 'user romm;'
	fi
}

start_bin_valkey-server() {
	info_log "Starting internal valkey-server"
	# Check if /usr/local/etc/valkey/valkey.conf exists and use it if so
	if [[ -f /usr/local/etc/valkey/valkey.conf ]]; then
		valkey-server /usr/local/etc/valkey/valkey.conf &
	else
		valkey-server --dir /redis-data &
	fi
	VALKEY_PID=$!
	echo "${VALKEY_PID}" >/tmp/valkey-server.pid
}

# function that runs our independent python scripts and creates corresponding PID files,
start_python() {
	SCRIPT="${1}"
	info_log "Starting ${SCRIPT}"
	python3 "${SCRIPT}.py" &
	WATCHER_PID=$!
	echo "${WATCHER_PID}" >"/tmp/${SCRIPT}.pid"
}

watchdog_process_pid() {
	TYPE=$1
	PROCESS=$2
	if [[ -f "/tmp/${PROCESS}.pid" ]]; then
		# check if the pid we last wrote to our state file is actually active
		PID=$(cat "/tmp/${PROCESS}.pid") || true
		if [[ -d "/proc/${PID}" ]]; then
			debug_log "${PROCESS} still running, no need to start"
		else
			if [[ ${TYPE} == "bin" ]]; then
				start_bin_"${PROCESS}"
			elif [[ ${TYPE} == "python" ]]; then
				start_python "${PROCESS}"
			fi
		fi
	else
		if [[ ${TYPE} == "bin" ]]; then
			start_bin_"${PROCESS}"
		elif [[ ${TYPE} == "python" ]]; then
			start_python "${PROCESS}"
		fi
	fi
}

stop_process_pid() {
	PROCESS=$1
	if [[ -f "/tmp/${PROCESS}.pid" ]]; then
		PID=$(cat "/tmp/${PROCESS}.pid") || true
		if [[ -d "/proc/${PID}" ]]; then
			info_log "Stopping ${PROCESS}"
			kill "${PID}" || true
			# wait for process exit
			while [[ -e "/proc/${PID}" ]]; do sleep 0.1; done
		fi
	fi
}

shutdown() {
	# shutdown in reverse order
	stop_process_pid scheduler
	stop_process_pid worker
	stop_process_pid watcher
	stop_process_pid nginx
	stop_process_pid gunicorn
	stop_process_pid valkey-server
}

# switch to backend directory
cd /backend || { error_log "/backend directory doesn't seem to exist"; }

# setup trap handler
exited=0
trap 'exited=1 && shutdown' SIGINT SIGTERM EXIT

# clear any leftover PID files
rm /tmp/*.pid -f

# function definition done, lets start our main loop
while ! ((exited)); do
	# Start Valkey server if we dont have a corresponding PID file
	# and REDIS_HOST is not set (which would mean we're using an external Redis/Valkey)
	if [[ -z ${REDIS_HOST:=""} ]]; then
		watchdog_process_pid bin valkey-server
	else
		warn_log "REDIS_HOST is set, not starting internal valkey-server"
	fi

	# Run needed database migrations on startup,
	# but only if it was not successful since the last full docker container start
	if [[ ${ALEMBIC_SUCCESS:="false"} == "false" ]]; then
		if alembic upgrade head; then
			info_log "Database schema migrations succeeded"
			ALEMBIC_SUCCESS="true"
		else
			error_log "Something went horribly wrong when running the database migrations"
		fi
	else
		debug_log "Database schema already upgraded during current container lifecycle"
	fi

	# start backend if we dont have a corresponding PID file
	watchdog_process_pid bin gunicorn

	# start nginx if we dont have a corresponding PID file
	watchdog_process_pid bin nginx

	# start worker if we dont have a corresponding PID file
	info_log "Starting worker"
	watchdog_process_pid python worker

	# only start the scheduler if enabled
	if [[ ${ENABLE_SCHEDULED_RESCAN} == "true" || ${ENABLE_SCHEDULED_UPDATE_SWITCH_TITLEDB} == "true" ]]; then
		# start scheduler if we dont have a corresponding PID file
		info_log "Starting scheduler"
		watchdog_process_pid python scheduler
	fi

	# only start the watcher if enabled
	if [[ ${ENABLE_RESCAN_ON_FILESYSTEM_CHANGE} == "true" ]]; then
		# start watcher if we dont have a corresponding PID file
		info_log "Starting watcher"
		watchdog_process_pid python watcher
	fi

	# check for died processes every 5 seconds
	sleep 5
done