# -*- mode: sh; sh-basic-offset: 3; indent-tabs-mode: nil; -*-
# vim: set filetype=sh sw=3 sts=3 expandtab autoindent:
#
# rdiff-backup handler script for backupninja
# requires rdiff-backup
#

### FUNCTIONS ###

function test_connection() {
   # given a user and host,
   # tests the connection.
   # if user or host is missing, returns 0
   # (ie, assume it's a local connection).
   if [ $# -lt 2 ]; then
      debug "(local is assumed to be a good connection)"
      return 0
   fi
   local user=$1
   local host=$2
   debug "ssh $sshoptions -o PasswordAuthentication=no $host -l $user 'echo -n 1'"
   local ret=`ssh $sshoptions -o PasswordAuthentication=no $host -l $user 'echo -n host is alive'`
   if echo $ret | grep "host is alive"; then
      debug "Connected to $host as $user successfully"
   else
      fatal "Can't connect to $host as $user."
   fi
}

function get_version() {
   # given no arguments, returns the local version.
   # given a user and host, returns the remote version.
   # if user or host is missing, returns the local version.
   local version
   if [ "$#" -lt 2 ]; then
      debug "$RDIFFBACKUP -V"
      echo `$RDIFFBACKUP -V`
   else
      local user=$1
      local host=$2
      debug "ssh $sshoptions $host -l $user '$RDIFFBACKUP -V'"
      version=`ssh $sshoptions $host -l $user "$RDIFFBACKUP -V"`
      if [ $? = 127 ]; then
         fatal "Unable to execute rdiff-backup on remote server. It probably isn't installed"
      else
         echo "$version" | grep rdiff-backup
      fi
   fi
}

function check_consistency() {
   local section=$1
   local type=$2
   local user=$3
   local host=$4
   if [ "$type" == "local" ]; then
      if [ "$user" != "" ]; then
         warning "User should not be specified for local $section."
      fi
      if [ "$host" != "" ]; then
         warning "Host should not be specified for local $section."
      fi
   fi
   if [ "$type" == "remote" ]; then
      if [ "$user" == "" ]; then
         fatal "User must be specified for remote $section."
      fi
      if [ "$host" == "" ]; then
         fatal "Host must be specified for remote $section."
      fi
   fi
}

function check_cstream() {
   local cstream=$1
   if [ ! -x $cstream ]; then
      fatal "Can't find your cstream binary (trying: $cstream). If you use bwlimit you must have cstream installed."
   fi
}

### GET CONFIG ###

getconf options
getconf testconnect yes
getconf nicelevel 0
getconf ionicelevel
getconf bwlimit
getconf ignore_version no
getconf output_as_info no

setsection source
getconf type; sourcetype=$type
getconf user; sourceuser=$user
getconf host; sourcehost=$host
check_consistency "source" "$type" "$user" "$host"
getconf label
getconf keep 60
getconf include
getconf exclude


setsection dest
getconf directory; destdir=$directory
# strip trailing /
destdir=${destdir%/}
getconf type; desttype=$type
getconf user; destuser=$user
getconf host; desthost=$host
getconf sshoptions
check_consistency "destination" "$type" "$user" "$host"

if [ -n "$sshoptions" ] && echo $options | grep -qv "remote-schema"; then
   options="$options --remote-schema 'ssh -C $sshoptions %s rdiff-backup --server'"
fi

### CHECK CONFIG ###

# Check that the ionicelevel is valid
if [ -n "$ionicelevel" ] && echo "$ionicelevel" | grep -vq "^[0-7]$"; then
   fatal "The value of ionicelevel is expected to be either empty or an integer from 0 to 7. Got: $ionicelevel"
fi

# Only use ionice if ionicelevel is not empty
nice="nice -n $nicelevel"
if [ -n "$ionicelevel" ]; then
   nice="ionice -c2 -n $ionicelevel $nice"
fi

# check the connection at the source and destination
[ -n "$test" ] || test=0
if [ "$testconnect" = "yes" ] || [ "${test}" -eq 1 ]; then
   test_connection $sourceuser $sourcehost
   test_connection $destuser $desthost
fi

if [ "$ignore_version" != "yes" ]; then
   # see that rdiff-backup has the same version at the source and destination
   debug "executing rdiff-backup version checks"
   sourceversion=`get_version $sourceuser $sourcehost`
   destversion=`get_version $destuser $desthost`
   debug "source version: $sourceversion"
   debug "destination version: $destversion"
   if [ "$sourceversion" != "$destversion" ]; then
      fatal "rdiff-backup does not have the same version at the source and at the destination."
   fi
fi

# source specific checks
case $sourcetype in
   remote ) execstr_sourcepart="$sourceuser@$sourcehost::/" ;;
   local  ) execstr_sourcepart="/" ;;
   *      ) fatal "sourcetype '$sourcetype' is neither local nor remote" ;;
esac

# destination specific checks
[ "$destdir" != "" ] || fatal "Destination directory not set"
case $desttype in
   remote ) execstr_destpart="$destuser@$desthost::$destdir/$label" ;;
   local  ) execstr_destpart="$destdir/$label" ;;
   *      ) fatal "desttype '$desttype' is neither local nor remote" ;;
esac

# check keep parameter format
if [ "$keep" != "yes" ] && ! echo "$keep" | grep -qe '^[0-9]\+[smhDWMY]\?$'; then
   fatal "Keep parameter contains an invalid value ($keep)."
fi

### REMOVE OLD BACKUPS ###

if [ "$keep" != yes ]; then

   if [ "`echo $keep | tr -d 0-9`" == "" ]; then
   # add D if no other date unit is specified
      keep="${keep}D"
   fi

   removestr="$RDIFFBACKUP $options --force --remove-older-than $keep "
   if [ "$desttype" == "remote" ]; then
      removestr="${removestr}${destuser}@${desthost}::"
   fi
   removestr="${removestr}${destdir}/${label}";

   debug "executing rdiff-backup --remove-older-than"
   debug "$removestr"
   if [ $test = 0 ]; then
      output="`su -c "$removestr" 2>&1`"
      if [ $? = 0 ]; then
         if [ "$output_as_info" == "yes" ]; then
            info "$output"
         else
            debug "$output"
         fi
         info "Removing backups older than $keep days succeeded."
      else
         warning "$output"
         warning "Failed removing backups older than $keep."
      fi
   fi

fi

# Add cstream

if [ ! -z $bwlimit ]; then
   check_cstream $CSTREAM;
   if [ "$desttype" = "remote" ]; then
      RDIFFBACKUP="$RDIFFBACKUP --remote-schema 'cstream -t $bwlimit | ssh %s \''rdiff-backup --server\'''"
   elif [ "$sourcetype" = "remote" ]; then
      RDIFFBACKUP="$RDIFFBACKUP --remote-schema 'ssh %s \''rdiff-backup --server\'' | cstream -t $bwlimit'"
   else
      fatal "You specified a bandwidth limit but neither your source nor destination types are remote."
   fi
fi

### EXECUTE ###

execstr="$RDIFFBACKUP $options --print-statistics "

set -o noglob

symlinks_warning="Maybe you have mixed symlinks and '*' in this statement, which is not supported."

# TODO: order the includes and excludes
# excludes
SAVEIFS=$IFS
IFS=$(echo -en "\n\b")
for i in $exclude; do
   str="${i//__star__/*}"
   case "$str" in
      @*) execstr="${execstr}--exclude-globbing-filelist '${str#@}' " ;;
      *) execstr="${execstr}--exclude '$str' " ;;
   esac
done
IFS=$SAVEIFS
# includes
SAVEIFS=$IFS
IFS=$(echo -en "\n\b")
for i in $include; do
   [ "$i" != "/" ] || fatal "Sorry, you cannot use 'include = /'"
   str="${i//__star__/*}"
   case "$str" in
   @*) execstr="${execstr}--include-globbing-filelist '${str#@}' " ;;
   *) execstr="${execstr}--include '$str' " ;;
   esac
done
IFS=$SAVEIFS

set +o noglob

# exclude everything else
[ "$include" != "" ] && execstr="${execstr}--exclude '/*' "

# include client-part and server-part
execstr="${execstr}$execstr_sourcepart $execstr_destpart"

debug "executing rdiff-backup"
debug "$nice $execstr"
if [ $test = 0 ]; then
   output=`$nice su -c "$execstr" 2>&1`
   if [ $? = 0 ]; then
      if [ "$output_as_info" == "yes" ]; then
         info "$output"
      else
         debug "$output"
      fi
      info "Successfully finished backing up source $label"
   else
      error "$output"
      fatal "Failed backup up source $label"
   fi
fi

return 0