#!/bin/sh

arg1() { echo "$1" ; }
getmnts() { sed '-es|_|/|g' ; }
getmnt() { echo "$1" | getmnts ; }
getstatus() { cat "$CTL/$1"/status ; }

getstate() {
  ctls="$(ls "$CTL")"
  for ctl in $ctls ; do
    st="$(getstatus "$ctl")"
    [ "$st" = "$1" ] && echo "$ctl"
  done
}

# Resync while write blocked and reanabe this copy
# before unblocking so that all further changes stay
# in sync.   Args are mount points.
msync() { # GOOD_MNT  BAD_MNT  BAD_STATUS
  if [ -z "$1" ] ; then
    usage
    echo "ERROR: You must specify the good mount point" >&2
    echo "" >&2
    exit
  fi
  if [ -z "$2" ] ; then
    usage
    echo "ERROR: You must specify the bad mount point" >&2
    echo "" >&2
    exit
  fi
  if [ -z "$3" ] ; then
    usage
    echo "ERROR: You must specify the bad status ctl file" >&2
    echo "" >&2
    exit
  fi

  echo "Resyncing with write block from $1  to  $2 (STAT:$3, RSYNC_OPTS:$RSYNC_OPTS)" >&2
  echo B > "$3"
  if  rsync $RSYNC_OPTS "$1/" "$2" ; then
    echo 0 > "$3"
    echo U > "$3"
    return
  fi
  echo U > "$3"
  return 1
}

presync() {
  typeset -i sw_num=1  n=0
  case "$1" in  -*) sw_num="${1:1}" ; shift ;;  esac
  good="$1" bad="$2"
  stg="$(getstatus "$good")"
  stb="$(getstatus "$bad")"

  [ "$stg" != "0" ] && return 1
  [ "$stb" != "2" ] && return 2

  mntg="$(getmnt "$good")"
  mntb="$(getmnt "$bad")"

  # Bring it up to date without blocking first since there
  # may be major changes from when the sync was lost
  while [ $n -lt $sw_num ] ; do
    n=$(($n +1))
    echo "Resyncing($n of $sw_num) from $mntg  to  $mntb (RSYNC_OPTS:$RSYNC_OPTS
)" >&2
    rsync $RSYNC_OPTS "$mntg/" "$mntb" || return 3
  done

  # Ensure 100% sync while write blocked (changes may have
  # already occured since the first sync!) and reenable this
  # copy before unblocking so that all further changes stay
  # in sync.  Hopefully there will be very few changes during
  # the write block since we just did a sync without
  # blocking to catch up.
  msync "$mntg" "$mntb" "$CTL/$bad/status"
}

usage()
{
  cat - >&2 <<EOF

  Usage(v1.0):

    $0 [options] [--ctl path_to_ctl_fs]

    Sync all outdated FSes

  OR

    $0 [options] [--sync good_mnt outdated_mnt outdated_ctl_fs]

    Sync a specific outdated FS


  Options:

  --rsyncopts <opts>   Flags for rsync.
                       The default are: $RSYNC_OPTS

  -1                   Only rysnc once (during write block)
  -2                   Presync before write blocking

EOF
}

RSYNC_OPTS='-a -A -H -X --numeric-ids --delete -S -c'
SW_NUM='-2'
READ=''
while [ $# -gt 0 ] ; do
  case "$1" in
    -h|-u|--help) usage ; exit ;;
    --ctl) shift ; CTL="$1" ;;
    --rsyncopts) shift ; RSYNC_OPTS="$1" ;;
    --sync) shift ; GMNT="$1" ; BMNT="$2" ; BCTL="$3" ; shift 2 ;;
    -1) SW_NUM="$1" ;;
    -2) SW_NUM="$1" ;;
    --read) shift ; READ="$READ $1" ;;

  esac
  shift
done

[ ! -z "$GMNT$BMNT$BCTL" ] && { msync "$GMNT" "$BMNT" "$BCTL" ; exit ; }

if [ -z "$CTL" ] ; then
  usage 
  echo "ERROR: You must provide the location of the CHIRCTL filesystem" >&2
  echo "" >&2
  exit
fi


debug() {
  for ctl in $CTLS ; do
    mnt="$(getmnt "$ctl")"
    st="$(getstatus "$ctl")"
    echo "MNT: $mnt, STATUS: $st" 
  done
}

GOOD="$(getstate 0)"
BAD="$(getstate 2)"

[ ! -z "$GOOD" ] && echo "GOOD: " $GOOD
[ ! -z "$BAD" ]  && echo "BAD: " $BAD

[ -z "$BAD" ] && exit

# which good one should we use (not :), but we don't have this info"

G="$(arg1 $GOOD)"

for bad in $BAD ; do
  presync $SW_NUM "$G" "$bad"
done


GOOD="$(getstate 0)"
BAD="$(getstate 2)"

[ ! -z "$GOOD" ] && echo "GOOD: " $GOOD
[ ! -z "$BAD" ]  && echo "BAD: " $BAD

[ ! -z "$BAD" ] && exit 1