#!/bin/sh
# shellcheck disable=SC2154

echo "INFO  [init] Gazebo simulator"

# Enforce minimum gz version as Harmonic (gz-sim8)
MIN_GZ_VERSION="8.0.0"
GZ_SIM_VERSION=$(gz sim --versions 2>/dev/null | head -n 1 | tr -d ' ')

if [ -z "$GZ_SIM_VERSION" ]; then
    echo "ERROR [init] Gazebo gz sim not found. Please install gz-harmonic"
    exit 1
fi

# Use sort compare, check that MIN_GZ_VERSION is ordered last
if [ "$(printf '%s\n' "$GZ_SIM_VERSION" "$MIN_GZ_VERSION" | sort -V | head -n1)" = "$MIN_GZ_VERSION" ]; then
	gz_command="gz"
	gz_sub_command="sim"

	# Specify render engine if `GZ_SIM_RENDER_ENGINE` is set
	# (for example, if you want to use Ogre 1.x instead of Ogre 2.x):
	if [ -n "${PX4_GZ_SIM_RENDER_ENGINE}" ]; then
		echo "INFO  [init] Setting Gazebo render engine to '${PX4_GZ_SIM_RENDER_ENGINE}'!"
		gz_sub_command="${gz_sub_command} --render-engine ${PX4_GZ_SIM_RENDER_ENGINE}"
	fi
else
    echo "ERROR [init] Gazebo gz sim version is too old ($GZ_SIM_VERSION). Minimum required version is $MIN_GZ_VERSION"
    exit 1
fi

# Look for an already running world
get_gz_world() {
	gz_world=$( ${gz_command} topic -l | grep -m 1 -e "^/world/.*/clock" | sed 's/\/world\///g; s/\/clock//g' )
}

# If not standalone
if [ -z "${PX4_GZ_STANDALONE}" ]; then

	get_gz_world

	# shellcheck disable=SC2153
	if [ -z "${gz_world}" ] && [ -n "${PX4_GZ_WORLD}" ]; then

		# Setup gz environment variables
		if [ -f ./gz_env.sh ]; then
			. ./gz_env.sh

		elif [ -f ../gz_env.sh ]; then
			. ../gz_env.sh
		fi

		echo "INFO  [init] Starting gazebo with world: ${PX4_GZ_WORLDS}/${PX4_GZ_WORLD}.sdf"

		${gz_command} ${gz_sub_command} --verbose=${GZ_VERBOSE:=1} -r -s "${PX4_GZ_WORLDS}/${PX4_GZ_WORLD}.sdf" &

		if [ -z "${HEADLESS}" ]; then
			echo "INFO  [init] Starting gz gui"
			${gz_command} ${gz_sub_command} -g > /dev/null 2>&1 &
		fi

	else
		# Gazebo is already running
		echo "INFO  [init] gazebo already running world: ${gz_world}"
		PX4_GZ_WORLD=${gz_world}
	fi

else
	echo "INFO  [init] Standalone PX4 launch, waiting for Gazebo"
fi

# Wait for Gazebo world to be ready before proceeding
check_scene_info() {

	get_gz_world

	if [ -n "${PX4_GZ_STANDALONE}" ] && [ -n "${gz_world}" ]; then
		PX4_GZ_WORLD=${gz_world}
	fi

	SERVICE_INFO=$(${gz_command} service -i --service "/world/${PX4_GZ_WORLD}/scene/info" 2>&1)
	if echo "$SERVICE_INFO" | grep -q "Service providers"; then
		return 0
	else
		return 1
	fi
}

ATTEMPTS=30
while [ $ATTEMPTS -gt 0 ]; do
	if check_scene_info; then
		echo "INFO  [init] Gazebo world is ready"
		break
	fi
	ATTEMPTS=$((ATTEMPTS-1))
	if [ $ATTEMPTS -eq 0 ]; then
		echo "ERROR [init] Timed out waiting for Gazebo world"
		exit 1
	fi
	echo "INFO  [init] Waiting for Gazebo world..."
	sleep 1
done

# Start gz_bridge - either spawn a model or connect to existing one
if [ -n "${PX4_SIM_MODEL#*gz_}" ] && [ -z "${PX4_GZ_MODEL_NAME}" ]; then
	# Spawn a model
	MODEL_NAME="${PX4_SIM_MODEL#*gz_}"
	MODEL_NAME_INSTANCE="${MODEL_NAME}_${px4_instance}"

	POSE_ARG=""
	if [ -n "${PX4_GZ_MODEL_POSE}" ]; then
		pos_x=$(echo "${PX4_GZ_MODEL_POSE}" | awk -F',' '{print $1}')
		pos_y=$(echo "${PX4_GZ_MODEL_POSE}" | awk -F',' '{print $2}')
		pos_z=$(echo "${PX4_GZ_MODEL_POSE}" | awk -F',' '{print $3}')
		pos_x=${pos_x:-0}
		pos_y=${pos_y:-0}
		pos_z=${pos_z:-0}

		POSE_ARG=", pose: { position: { x: ${pos_x}, y: ${pos_y}, z: ${pos_z} } }"
		echo "INFO  [init] Spawning model at position: ${pos_x} ${pos_y} ${pos_z}"
	fi

	echo "INFO  [init] Spawning model"

	# Spawn model
	${gz_command} service -s "/world/${PX4_GZ_WORLD}/create" --reqtype gz.msgs.EntityFactory \
			--reptype gz.msgs.Boolean --timeout 5000 \
			--req "sdf_filename: \"${PX4_GZ_MODELS}/${MODEL_NAME}/model.sdf\", name: \"${MODEL_NAME_INSTANCE}\", allow_renaming: false${POSE_ARG}" > /dev/null 2>&1

	# Wait for model to spawn
	sleep 1

	# Start gz_bridge
	if ! gz_bridge start -w "${PX4_GZ_WORLD}" -n "${MODEL_NAME_INSTANCE}"; then
		echo "ERROR [init] gz_bridge failed to start and spawn model"
		exit 1
	fi

	# Set physics parameters for faster-than-realtime simulation if needed
	if [ -n "${PX4_SIM_SPEED_FACTOR}" ]; then
		echo "INFO  [init] Setting simulation speed factor: ${PX4_SIM_SPEED_FACTOR}"
		${gz_command} service -s "/world/${PX4_GZ_WORLD}/set_physics" --reqtype gz.msgs.Physics \
					--reptype gz.msgs.Boolean --timeout 5000 \
					--req "real_time_factor: ${PX4_SIM_SPEED_FACTOR}" > /dev/null 2>&1
	fi

	# Set up camera to follow the model if requested
	if [ -n "${PX4_GZ_FOLLOW}" ]; then

		echo "INFO  [init] Setting camera to follow ${MODEL_NAME_INSTANCE}"

		# Set camera to follow the model
		${gz_command} service -s "/gui/follow" --reqtype gz.msgs.StringMsg \
				--reptype gz.msgs.Boolean --timeout 5000 \
				--req "data: \"${MODEL_NAME_INSTANCE}\"" > /dev/null 2>&1

		# Set default camera offset if not specified
		follow_x=${PX4_GZ_FOLLOW_OFFSET_X:--2.0}
		follow_y=${PX4_GZ_FOLLOW_OFFSET_Y:--2.0}
		follow_z=${PX4_GZ_FOLLOW_OFFSET_Z:-2.0}

		# Set camera offset
		${gz_command} service -s "/gui/follow/offset" --reqtype gz.msgs.Vector3d \
				--reptype gz.msgs.Boolean --timeout 5000 \
				--req "x: ${follow_x}, y: ${follow_y}, z: ${follow_z}" > /dev/null 2>&1

		echo "INFO  [init] Camera follow offset set to ${follow_x}, ${follow_y}, ${follow_z}"
	fi

elif [ -n "${PX4_GZ_MODEL_NAME}" ]; then
	# Connect to existing model
	echo "INFO  [init] PX4_GZ_MODEL_NAME set, PX4 will attach to existing model"
	if ! gz_bridge start -w "${PX4_GZ_WORLD}" -n "${PX4_GZ_MODEL_NAME}"; then
		echo "ERROR [init] gz_bridge failed to start and attach to existing model"
		exit 1
	fi
else
	echo "ERROR [init] failed to pass either PX4_GZ_MODEL_NAME or PX4_SIM_MODEL"
	exit 1
fi

# NOTE: Only for rover_mecanum and spacecraft_2d. All other models have
# the magnetometer sensor in the model.sdf.
if param compare -s SENS_EN_MAGSIM 1
then
	sensor_mag_sim start
fi
# NOTE: new gz has airspeed sensor, remove once added
if param compare -s SENS_EN_ARSPDSIM 1
then
	sensor_airspeed_sim start
fi