#!/bin/bash

# Read the server list from the specified file
SERVER_LIST_FILE="servers.conf"
SERVER_LIST=()
while IFS= read -r SERVER || [[ -n "$SERVER" ]]; do
  SERVER_LIST+=("$SERVER")
done < "$SERVER_LIST_FILE"

# Loop through the server list
for SERVER in "${SERVER_LIST[@]}"
do
  echo "Checking for updates on server: ${SERVER}"
  
  # Establish SSH connection to remote server and run commands to check for updates
  SSH_RESULT=$(ssh root@${SERVER} "sudo apt-get update > /dev/null && apt list --upgradable")

  # If updates are available, inform the user
  if [ -n "${SSH_RESULT}" ]; then
    echo "Updates available on server ${SERVER}:"
    echo "${SSH_RESULT}"
    echo ""
  else
    echo "No updates available on server ${SERVER}"
    echo ""
  fi
done

# Prompt user to confirm if they want to update the listed servers
read -p "Do you want to update the listed servers? (Yes/No): " UPDATE_CONFIRMATION

# If the user confirms with "Yes", update the servers and store the update status for each server in a list
if [[ $UPDATE_CONFIRMATION == "Yes" ]]; then
  UPDATE_STATUS=()
  for SERVER in "${SERVER_LIST[@]}"
  do
    echo "Updating server: ${SERVER}"
  
    # Establish SSH connection to remote server and run commands to update
    ssh root@${SERVER} "sudo apt-get update > /dev/null && sudo apt-get upgrade -y" > /dev/null 2>&1
  
    # Check the return value of ssh to determine if the update was successful
    if [[ $? -eq 0 ]]; then
      UPDATE_STATUS+=("${SERVER}: Update successful")
      echo "Server ${SERVER} updated."
    else
      UPDATE_STATUS+=("${SERVER}: Update failed")
      echo "Failed to update server ${SERVER}."
    fi
  done

  # Summary of update status
  echo ""
  echo "Summary of update status:"
  for STATUS in "${UPDATE_STATUS[@]}"
  do
    echo "${STATUS}"
  done
else
  echo "Updates cancelled."
fi