#!/bin/bash
 
echo "Installing snap package"
# helper function to set error output
function error_exit
{
  echo "$1" 1>&2
  exit 1
}
 
# check parameters for registering managed instance
DO_REGISTER=false
if [ "$1" == "register-managed-instance" ]; then
  if [ $# -eq 4 ]; then
		DO_REGISTER=true
		RMI_CODE=$2
		RMI_ID=$3
		RMI_REGION=$4
  else
		error_exit '[ERROR] Not enough parameters for RegisterManagedInstance.'
  fi
fi

if [[ "$(cat /proc/1/comm)" == "systemd" ]]; then
 
  if [[ "$(systemctl is-active snap.amazon-ssm-agent.amazon-ssm-agent.service)" == "active" ]]; then
    echo "detected snap amazon-ssm-agent running on the system, installing new snaps..."
    # stop the current agent
    systemctl stop snap.amazon-ssm-agent.amazon-ssm-agent.service
    echo 'SSM Agent uninstalled'
  else
    echo "-> Agent is not running in the instance "
  fi

  if [[ ! -f amazon-ssm-agent.snap || ! -f amazon-ssm-agent.assert ]]; then
    echo '[ERROR] Snap is not available for this version. Please uninstall the snap and install a debian if this agent version is required.'
    exit 1
  fi

  # acknowledge the signature pulled from the s3 distro
  snap ack amazon-ssm-agent.assert
  # install snap in classic mode
  echo 'installing snap'
  snap install --classic amazon-ssm-agent.snap
  pmExit=$?

  # register onprem instance
  if [ "$DO_REGISTER" = true ]; then
    snap stop amazon-ssm-agent
    SNAP_BIN=/snap/amazon-ssm-agent/current
    "$SNAP_BIN"/amazon-ssm-agent -register -code "$RMI_CODE" -id "$RMI_ID" -region "$RMI_REGION"
  fi

  echo "Starting agent..."
  snap start amazon-ssm-agent

  if [ "$pmExit" -ne 0 ]; then
    echo "Package manager failed with exit code '$pmExit'"
    exit 125
  fi

else
  echo '[ERROR] Snap install is not supported on this instance. Please uninstall the snap agent and try again' 1>&2
  exit 124
fi