#!/bin/sh

set -e

# Path that initial installation files are copied to
INIT_JAR_PATH=/opt/greengrassv2

# Allow the root user to execute commands as other users
modify_sudoers() {

	# Grab the line number for the root user entry
	ROOT_LINE_NUM=$(grep -n "^root" /etc/sudoers | cut -d : -f 1)

	# Check if the root user is already configured to execute commands as other users
	if sudo sed -n "${ROOT_LINE_NUM}p" /etc/sudoers | grep -q "ALL=(ALL:ALL)" ; then
		echo "Root user is already configured to execute commands as other users."
		return 0
  	fi

	echo "Attempting to safely modify /etc/sudoers..."

  	# Take a backup of /etc/sudoers
	sudo cp /etc/sudoers /tmp/sudoers.bak

	# Replace `ALL=(ALL)` with `ALL=(ALL:ALL)` to allow the root user to execute commands as other users
	sudo sed -i "$ROOT_LINE_NUM s/ALL=(ALL)/ALL=(ALL:ALL)/" /tmp/sudoers.bak

	# Validate syntax of backup file
	sudo visudo -cf /tmp/sudoers.bak
	if [ $? -eq 0 ]; then
		# Replace the sudoers file with the new only if syntax is correct.
		sudo mv /tmp/sudoers.bak /etc/sudoers
		echo "Successfully modified /etc/sudoers. Root user is now configured to execute commands as other users."
	else
		echo "Error while trying to modify /etc/sudoers, please edit manually."
		exit 1
	fi
}

OPTIONS="-Droot=${GGC_ROOT_PATH} -Dlog.store=FILE -Dlogging.outputDirectory=/logs -Dlog.level=${LOG_LEVEL} -jar ${INIT_JAR_PATH}/lib/Greengrass.jar --provision ${PROVISION} --deploy-dev-tools ${DEPLOY_DEV_TOOLS} --start true"

echo "Using the following option: $OPTIONS"

# If provision is true
if [ ${PROVISION} = "true" ]; then

	if [ ! -f "/root/.aws/credentials" ]; then
		echo "Provision is set to true, but credentials file does not exist at /root/.aws/credentials . Please mount to this location and retry."
		exit 1
	fi

	# If thing name is specified, add optional argument
	# If not specified, reverts to default of "GreengrassV2IotThing_" plus a random UUID.
	if [ ${THING_NAME} != default_thing_name ]; then
	    OPTIONS="${OPTIONS} --thing-name ${THING_NAME}"

	    # If thing group name is specified, add optional argument
	    if [ ${THING_GROUP_NAME} != default_thing_group_name ]; then
	    	OPTIONS="${OPTIONS} --thing-group-name ${THING_GROUP_NAME}"
		fi
	fi
fi

# If TES role name is specified, add optional argument
# If not specified, reverts to default of "GreengrassV2TokenExchangeRole"
if [ ${TES_ROLE_NAME} != default_tes_role_name ]; then
	OPTIONS="${OPTIONS} --tes-role-name ${TES_ROLE_NAME}"
fi

# If TES role name is specified, add optional argument
# If not specified, reverts to default of "GreengrassV2TokenExchangeRoleAlias"
if [ ${TES_ROLE_ALIAS_NAME} != default_tes_role_alias_name ]; then
	OPTIONS="${OPTIONS} --tes-role-alias-name ${TES_ROLE_ALIAS_NAME}"
fi

# If component default user is specified, add optional argument
# If not specified, reverts to ggc_user:ggc_group 
if [ ${COMPONENT_DEFAULT_USER} != default_component_user ]; then
	OPTIONS="${OPTIONS} --component-default-user ${COMPONENT_DEFAULT_USER}"
fi

# Use optional init config argument
# If this option is specified, the config file must be mounted to this location
if [ ${INIT_CONFIG} != default_init_config ]; then
	if [ -f ${INIT_CONFIG} ]; then
		echo "Using specified init config file at ${INIT_CONFIG}"
		OPTIONS="${OPTIONS} --init-config ${INIT_CONFIG}"
    else
    	echo "WARNING: Specified init config file does not exist at ${INIT_CONFIG} !"
    fi
fi

echo "Running Greengrass with the following options: ${OPTIONS}"

# If we have not already installed Greengrass
if [ ! -d $GGC_ROOT_PATH/alts/current/distro ]; then
	# Install Greengrass via the main installer, but do not start running
	echo "Installing Greengrass for the first time..."
	modify_sudoers
	java ${OPTIONS}
else
	echo "Reusing existing Greengrass installation..."
fi

#Make loader script executable
echo "Making loader script executable..."
chmod +x $GGC_ROOT_PATH/alts/current/distro/bin/loader

echo "Starting Greengrass..."

# Start greengrass kernel via the loader script and register container as a thing
sh $GGC_ROOT_PATH/alts/current/distro/bin/loader