#!/bin/bash

# remote backup support-script

# rotate: renames backups: name.03->name.04, name.02->name.03 <etc.>
# prepare: creates new backup directory name.00
# cleanup: removes all backup directories whose numbers exceed a limit

# configuration

backupRoot="/data/backups"

# --- rotate backups --------

rotate() {
  remoteHost="$1"
  backupType="$2"

  backupDir="$backupRoot/$remoteHost"

  find "$backupDir/$backupType."* -type d -maxdepth 0 | sort -r | while read dir; do
    nr="${dir##*.}"
    nr="${nr#0}"
    let nr1=nr+1
    nr1=`printf "%02d" $nr1`
    mv "$dir" "$backupDir/$backupType.$nr1"
  done
}

# --- prepare backup -------

prepare() {
  remoteHost="$1"
  backupType="$2"
  backupDir="$backupRoot/$remoteHost"
  targetDir="$backupDir/$backupType.00"

  mkdir -p "$targetDir"
  echo "$targetDir"
  exit 0
}

# --- delete old backup ------

cleanup() {
  remoteHost="$1"
  backupType="$2"
  maxGen="$3"
  backupDir="$backupRoot/$remoteHost"

  while [ $maxGen -lt 100 ]; do
    nr=`printf "%02d" $maxGen`
    if [ ! -d "$backupDir/$backupType.$nr" ]; then
      exit 0
    else
      rm -fr "$backupDir/$backupType.$nr"
      let maxGen=maxGen+1
    fi
  done
}

# --- main program -------

func="$1"
# check allowed function
grep -qw "$func" <<< "prepare rotate cleanup" || exit 3
shift
eval $func "$@"