#!/bin/bash

source /mnt/hdd/raspiblitz.conf

# command info
if [ $# -eq 0 ] || [ "$1" = "-h" ] || [ "$1" = "-help" ]; then
 echo "# small rescue script to to backup or restore LND data"
 echo "# -> backup all LND data in a tar.gz file for download:"
 echo "# lnd.rescue.sh backup [?no-download]"
 echo "# -> upload a LND data tar.gz file to replace LND data:"
 echo "# lnd.rescue.sh restore"
 echo "# -> download the LND channel.backup file from SD card:"
 echo "# lnd.rescue.sh scb-down"
 echo "# -> upload the LND channel.backup to recover wallet:"
 echo "# lnd.rescue.sh scb-up"
 exit 1
fi

localip=$(ip addr | grep 'state UP' -A2 | egrep -v 'docker0|veth' | grep 'eth0\|wlan0\|enp0' | tail -n1 | awk '{print $2}' | cut -f1 -d'/')

mode="$1"
if [ ${mode} = "backup" ]; then

  ################################
  # BACKUP
  ################################

  echo "# *** LND.RESCUE --> BACKUP"

  # stop LND
  echo "# Stopping lnd..."
  sudo systemctl stop lnd
  sleep 5
  echo "# OK"
  echo 

  # zip it
  sudo tar -zcvf /home/admin/lnd-rescue.tar.gz /mnt/hdd/lnd 1>&2
  sudo chown admin:admin /home/admin/lnd-rescue.tar.gz 1>&2

  # delete old backups
  rm /home/admin/lnd-rescue-*.tar.gz 2>/dev/null 1>/dev/null

  # name with md5 checksum
  md5checksum=$(md5sum /home/admin/lnd-rescue.tar.gz | head -n1 | cut -d " " -f1)
  mv /home/admin/lnd-rescue.tar.gz /home/admin/lnd-rescue-${md5checksum}.tar.gz 1>&2
  echo "file='lnd-rescue-${md5checksum}.tar.gz'"
  echo "path='/home/admin/'"

  byteSize=$(ls -l /home/admin/lnd-rescue-${md5checksum}.tar.gz | awk '{print $5}')
  echo "size=${byteSize}"

  if [ ${byteSize} -lt 100 ]; then
    echo "error='backup is empty'"
    echo
    echo "# *****************************"
    echo "# * BACKUP ERROR              *"
    echo "# *****************************"
    echo "# The byte size of the created rescue-file is too small (${byteSize}) - might be empty!"
    echo "# If you plan any update or recovery please stop and report this error to dev team. Thx."
    exit 0
  fi

  # stop here in case of 'no-download' option
  if [ "${2}" == "no-download" ]; then
    echo "# No download of LND data requested."
    exit 0
  fi

  # offer SCP for download
  clear
  echo
  echo "****************************"
  echo "* DOWNLOAD THE RESCUE FILE *"
  echo "****************************"
  echo 
  echo "ON YOUR MAC & LINUX LAPTOP - RUN IN NEW TERMINAL:"
  echo "scp -r 'admin@${localip}:/home/admin/lnd-rescue-*.tar.gz' ./"
  echo "ON WINDOWS USE:"
  echo "scp -r admin@${localip}:/home/admin/lnd-rescue-*.tar.gz ./"
  echo ""
  echo "Use password A to authenticate file transfer."
  echo "Check for correct file size after transfer: ${byteSize} byte"
  echo
  echo "BEWARE: Your Lightning node is now stopped. It's safe to backup the data and"
  echo "restore it on a fresh RaspiBlitz. But once this Lightning node gets started"
  echo "again or rebooted, it's not advised to restore the backup file because"
  echo "it would contain outdated channel data and can lead to loss of channel funds."

elif [ ${mode} = "restore" ]; then

  ################################
  # RESTORE
  ################################

  echo "# LND.RESCUE --> RESTORE"
  echo ""

  # delete old backups
  rm /home/admin/lnd-rescue-*.tar.gz

  filename=""
  while [ ${#filename} -eq 0 ]
    do
      countZips=$(sudo ls /home/admin/lnd-rescue-*.tar.gz 2>/dev/null | grep -c 'lnd-rescue')
      if [ ${countZips} -lt 1 ]; then
        echo "**************************"
        echo "* UPLOAD THE RESCUE FILE *"
        echo "**************************"
        echo "If you have a lnd-rescue backup file on your laptop you can now"
        echo "upload it and restore the your latest LND state."
        echo
        echo "CAUTION: Dont restore old LND states - risk of loosing funds!"
        echo
        echo "To make upload open a new terminal on your laptop,"
        echo "change into the directory where your lnd-rescue file is and"
        echo "COPY, PASTE AND EXECUTE THE FOLLOWING COMMAND:"
        echo "scp -r ./lnd-rescue-*.tar.gz admin@${localip}:/home/admin/"
        echo ""
        echo "Use password A to authenticate file transfer."
        echo "PRESS ENTER when upload is done."
      fi
      if [ ${countZips} -gt 1 ]; then
        echo "!! WARNING !!"
        echo "There are multiple lnd-rescue files in directory /home/admin."
        echo "Make sure you upload only one tar.gz-file and start again."
        echo 
        echo "PRESS ENTER to continue."
        read key
        exit 1
      fi
      if [ ${countZips} -eq 1 ]; then
        
        clear
        echo
        echo "**************************"
        echo "* RESTORING BACKUP FILE  *"
        echo "**************************"
        echo

        filename=$(sudo ls /home/admin/lnd-rescue-*.tar.gz)
        echo "OK -> found file to restore: ${filename}"

        # checksum test
        md5checksum=$(md5sum ${filename} | head -n1 | cut -d " " -f1)
        isCorrect=$(echo ${filename} | grep -c ${md5checksum})
        if [ ${isCorrect} -eq 1 ]; then
          echo "OK -> checksum looks good: ${md5checksum}"
        else
          echo "!!! FAIL -> Checksum not correct."
          echo "Maybe transfer failed? Continue at your own risk!"
          echo "It is recommended to abort and upload again!"
        fi

        # overrride test
        oldWalletExists=$(sudo ls /mnt/hdd/lnd/data/chain/${network}/${chain}net/wallet.db 2>/dev/null | grep -c "wallet.db")
        if [ ${oldWalletExists} -gt 0 ]; then
          echo
          echo "WARNING: This will delete/overwrite the LND state/funds of this RaspiBlitz."
        fi
        echo
        echo "PRESS ENTER to start restore. Enter x & ENTER to cancel."
      fi
      read key
      if [ "${key}" == "x" ]; then
        exit 1
      fi
    done

  # stop LND
  echo "Stopping lnd..."
  sudo systemctl stop lnd
  sleep 5
  echo "OK"
  echo 

  # clean DIR
  echo "Cleaning LND data ..."
  sudo rm -r /mnt/hdd/lnd/*
  echo "OK"
  echo 

  # unpack zip
  echo "Restoring LND data from ${filename} ..."
  sudo tar -xf ${filename} -C /
  sudo chown -R bitcoin:bitcoin /mnt/hdd/lnd
  echo "OK"
  echo

  # check if LND needs update
  # (if RaspiBlitz has an optional LND version update, then install it
  # the newer LND version can always handle older data)
  echo "Checking LND version ..."
  source <(sudo -u admin /home/admin/config.scripts/lnd.update.sh info)
  if [ ${lndUpdateInstalled} -eq 0 ]; then
    echo "Installing available LND update ... (newer version can handle more wallet formats)"
    sudo -u admin /home/admin/config.scripts/lnd.update.sh verified
  else
    echo "OK"
  fi
  echo

  # start LND
  echo "Starting lnd..."
  sudo systemctl start lnd
  echo "OK"
  echo

  echo "DONE - please check if LND starts up correctly with restored state and funds."
  echo "Keep in mind that some channels maybe forced closed in the meanwhile."
  echo 

elif [ ${mode} = "scb-down" ]; then

  echo
  echo "****************************"
  echo "* DOWNLOAD THE BACKUP FILE *"
  echo "****************************"
  echo 
  echo "RUN THE FOLLOWING COMMAND ON YOUR LAPTOP IN NEW TERMINAL:"
  echo "scp -r admin@${localip}:/home/admin/.lnd/data/chain/${network}/${chain}net/channel.backup ./"
  echo ""
  echo "Use password A to authenticate file transfer."
  echo
  echo "NOTE: Use this file when setting up a fresh RaspiBlitz by choosing" 
  echo "option OLD WALLET and then SCB+SEED -> Seed & channel.backup file" 
  echo "Will just recover on-chain & channel-funds, but closing all channels" 

elif [ ${mode} = "scb-up" ]; then

  gotFile=-1
  while [ ${gotFile} -lt 1 ]
  do

    # show info
    clear
    sleep 1
    echo "**********************************"
    echo "* UPLOAD THE channel.backup FILE *"
    echo "**********************************"
    echo
    if [ ${gotFile} -eq -1 ]; then
      echo "If you have the channel.backup file on your laptop or on"
      echo "another server you can now upload it to the RaspiBlitz."
    elif [ ${gotFile} -eq 0 ]; then
      echo "NO channel.backup FOUND IN /home/admin"
      echo "Please try upload again."
    fi
    echo
    echo "To make upload open a new terminal and change,"
    echo "into the directory where your lnd-rescue file is and"
    echo "COPY, PASTE AND EXECUTE THE FOLLOWING COMMAND:"
    echo "scp ./channel.backup admin@${localip}:/home/admin/"
    echo ""
    echo "Use password A to authenticate file transfer."
    echo "PRESS ENTER when upload is done. Enter x & ENTER to cancel."

    # wait user interaction
    echo "Please upload file. Press ENTER to try again or (x & ENTER) to cancel."
    read key
    if [ "${key}" == "x" ]; then
      # EXIT with CODE 1 --> USER CANCEL
      echo "# CANCEL upload"
      exit 1
    fi

    # test upload
    gotFile=$(ls /home/admin/channel.backup | grep -c 'channel.backup')

  done

  # EXIT with CODE 1 --> FILE UPLOADED
  echo
  echo "# OK channel.backup uploaded"
  sleep 2
  exit 0

else
  echo "unknown parameter '${mode}' - exit"
fi