#!/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

# use virtualenvs
# shellcheck disable=SC1091
source /backend/bin/activate

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

# 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 [[ ${INIT_DEBUG} == "true" ]]; then
		echo "DEBUG:    [init][$(date +"%Y-%m-%d %T")]" "${@}" || true
	fi
}

# print debug log output if enabled
info_log() {
	echo "INFO:     [init][$(date +"%Y-%m-%d %T")]" "${@}" || true
}

# print error log output if enabled
error_log() {
	echo "ERROR:    [init][$(date +"%Y-%m-%d %T")]" "${@}" || true
	exit 1
}

# 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 gunicorn"
	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 \
		--workers "${GUNICORN_WORKERS:=2}" \
		main:app &
}

# Commands to start nginx (handling PID creation internally)
start_bin_nginx() {
	info_log "starting nginx"
	if [[ ${EUID} -ne 0 ]]; then
		nginx
	else
		# if container runs as root, drop permissions
		nginx -g 'user romm;'
	fi
}

start_bin_redis-server() {
	info_log "starting redis-server"

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

# function that runs our independent python scripts and creates corresponding PID files,
start_python() {
	SCRIPT="${1}"
	info_log "starting ${SCRIPT}.py"
	python3 "${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
}

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

info_log "Starting up, please wait..."

# function definition done, lets start our main loop
while true; do
	# check for died processes every 5 seconds
	sleep 5

	# Start redis server if we dont have a corresponding PID file
	# and REDIS_HOST is not set (which would mean we're using an external redis)
	if [[ -z ${REDIS_HOST:=""} ]]; then
		watchdog_process_pid bin redis-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
			debug_log "database schema migrations suceeded"
			ALEMBIC_SUCCESS="true"
		else
			error_log "Something went horribly wrong with our database"
		fi
	else
		debug_log "database schema already upgraded during current container lifecycle"
	fi

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

	# Start uvicorn if we dont have a corresponding PID file
	watchdog_process_pid bin gunicorn

	# only start the watcher.py if we actually want to use the rescan on fs change feature
	if [[ ${ENABLE_RESCAN_ON_FILESYSTEM_CHANGE} == "true" ]]; then
		# Start watcher if we dont have a corresponding PID file
		watchdog_process_pid python watcher
	fi

	# Start background worker processes
	debug_log "Starting worker and scheduler"
	# Start worker if we dont have a corresponding PID file
	watchdog_process_pid python worker
	# Start scheduler if we dont have a corresponding PID file
	watchdog_process_pid python scheduler
done