#!/bin/bash

# -- net-home-backup -- aka "nfs-backer" v1.6 - July 06, 2025 -- BTA / LOSTGEEK.NET --

# CONFIG
NFS_MOUNT="/mnt/nfs"
NFS_SHARE="$NFS_MOUNT/Share/net-home-bk"
CLIENT_HOSTNAME=$(hostname)
LOCKFILE="/tmp/net-home-backup.lock"
MASTER_LOG="$NFS_SHARE/backup.log"
DATESTAMP=$(date '+%m/%d/%y %H:%M')
FORCE=0
INTERACTIVE=0
ROOTMODE=0

# Show help
show_help() {
  echo "Usage: $0 [options]"
  echo ""
  echo "Options:"
  echo "  -i, --interactive   Prompt before syncing if diff detected"
  echo "  -f, --force         Disable 10GB diff limit check"
  echo "  -r, --root          Backup /root/ instead of /home/ben/"
  echo "  -h, --help          Show this help message"
  exit 0
}

# Parse options
while [ $# -gt 0 ]; do
  case "$1" in
    -i|--i|--interactive) INTERACTIVE=1 ;;
    -f|--f|--force) FORCE=1 ;;
    -r|--r|--root) ROOTMODE=1 ;;
    -h|--h|--help) show_help ;;
    *) echo "Unknown option: $1" && show_help ;;
  esac
  shift
done

# Lockfile to prevent concurrent runs
[ -f "$LOCKFILE" ] && echo "Backup already running." && exit 1
touch "$LOCKFILE"
trap "rm -f $LOCKFILE" EXIT

# Ensure NFS mount exists
if [ ! -d "$NFS_SHARE" ]; then
  echo "Mounting NFS share..."
  sudo mkdir -p "$NFS_MOUNT"
  sudo chown "$USER":"$USER" "$NFS_MOUNT"
  sudo mount -t nfs novo.lan:/mnt/sda1 "$NFS_MOUNT" || { echo "Mount failed"; exit 1; }
fi

# Determine source and destination
if [ "$ROOTMODE" -eq 1 ]; then
  SRC="/root/"
  DEST="$NFS_SHARE/$CLIENT_HOSTNAME/root"
else
  SRC="/home/ben/"
  DEST="$NFS_SHARE/$CLIENT_HOSTNAME"
fi

# Create destination directory if missing
mkdir -p "$DEST"

# Rsync options and include/exclude list
RSYNC_OPTS=(-a -x --delete --stats --info=progress2)

INCLUDES=(
  --include='.bashrc'
  --include='.xinitrc'
  --include='.xsession'
  --include='.ssh/***'
)

EXCLUDES=(
  --exclude='.*'
  --exclude='Downloads/'
  --exclude='VirtualBox VMs/'
)

# Dry-run to estimate transfer size
RSYNC_DRYRUN_OUTPUT=$(rsync "${RSYNC_OPTS[@]}" "${INCLUDES[@]}" "${EXCLUDES[@]}" --dry-run "$SRC" "$DEST")
TOTAL_SIZE_BYTES=$(echo "$RSYNC_DRYRUN_OUTPUT" | awk '/Total transferred file size:/ {print $5}')
TOTAL_SIZE_BYTES=${TOTAL_SIZE_BYTES//,/}
TOTAL_SIZE_MB=$(( TOTAL_SIZE_BYTES / 1048576 ))
TOTAL_SIZE_GB=$(awk "BEGIN {printf \"%.2f\", $TOTAL_SIZE_MB/1024}")

# Interactive check if requested
if [ "$INTERACTIVE" -eq 1 ]; then
  LAST_SYNC_FILE="$DEST/last_backup.txt"
  if [ -f "$LAST_SYNC_FILE" ]; then
    LAST_SYNC=$(cat "$LAST_SYNC_FILE")
  else
    LAST_SYNC="Never"
  fi

  echo "Last sync was: $LAST_SYNC"
  echo "Estimated new data to sync: $TOTAL_SIZE_MB MB ($TOTAL_SIZE_GB GB)"
  read -p "Proceed? (Y/N): " PROCEED
  [[ "$PROCEED" =~ ^[Yy]$ ]] || { echo "Aborting."; exit 0; }
fi

# Bail if diff is over 10GB and no force flag
if [ "$FORCE" -eq 0 ]; then
  if awk "BEGIN {exit !($TOTAL_SIZE_MB > 10240)}"; then
    echo "Sync exceeds 10GB. Use -f or --force to override."
    exit 1
  fi
fi

# Perform actual rsync
echo "Starting sync..."
RSYNC_OUTPUT=$(rsync "${RSYNC_OPTS[@]}" "${INCLUDES[@]}" "${EXCLUDES[@]}" "$SRC" "$DEST")
echo "$RSYNC_OUTPUT" > /tmp/rsync_log.txt

# Extract transfer size from rsync output
ACTUAL_TRANSFER_BYTES=$(grep 'Total transferred file size:' /tmp/rsync_log.txt | awk '{print $5}')
ACTUAL_TRANSFER_BYTES=${ACTUAL_TRANSFER_BYTES//,/}
ACTUAL_TRANSFER_MB=$(( ACTUAL_TRANSFER_BYTES / 1048576 ))
ACTUAL_TRANSFER_GB=$(awk "BEGIN {printf \"%.2f\", $ACTUAL_TRANSFER_MB/1024}")

# Update last backup time
echo "$DATESTAMP" > "$DEST/last_backup.txt"

# Determine if this was an initial or change run
if [ ! -f "$DEST/.initial_done" ]; then
  RUN_TYPE="Initial"
  touch "$DEST/.initial_done"
else
  RUN_TYPE="Change"
fi

# Append to master log
echo "$DATESTAMP $RUN_TYPE backup run on $CLIENT_HOSTNAME -- $ACTUAL_TRANSFER_GB GB" >> "$MASTER_LOG"

# Summary output
echo ""
echo "Backup complete."
echo "Summary for $CLIENT_HOSTNAME:"
echo "----------------------------------------------"
echo "New data transferred: $ACTUAL_TRANSFER_MB MB ($ACTUAL_TRANSFER_GB GB)"
echo ""
echo "Contents of $DEST:"
ls -lh "$DEST"
echo ""
echo "Total size of $CLIENT_HOSTNAME directory on NFS share:"
du -sh "$DEST"
echo "----------------------------------------------"
echo ""

exit 0