#!/bin/bash
export BTRFS_BIN=$(which btrfs)
module_load confirm
module_load helpers

# set this for sudo
# ALL ALL = (root) NOPASSWD:/bin/btrfs

make_subvol() {
  local usesudo
  local uid
  local gid
  [[ $EUID -ne 0 ]] && usesudo=sudo
  uid=${2:-$USER}
  gid=${3:-$uid}
  mkdir -p $(dirname $1) &> /dev/null
  echo $usesudo $BTRFS_BIN subvolume create $1
  $usesudo $BTRFS_BIN subvolume create $1
  echo $usesudo chown $uid:$gid $1
  $usesudo chown $uid:$gid $1
}

del_subvol() {
  local usesudo; local delete
  [[ $1 == "-d" ]] && delete=true && shift
  [[ $EUID -ne 0 ]] && usesudo=sudo
  if $usesudo $BTRFS_BIN subvolume show "$1" &> /dev/null; then
    if [[ -v PS1 && ! $delete ]]; then
     confirm "DELETE the subvolume $(realpath "$1") (pass -d to avoid confirm)" || return 1
    fi
    $usesudo $BTRFS_BIN subvolume delete $1
   else 
    echo "$1 not a btrfs subvolume, nothing to delete"
  fi

}

# make_base_subvols() {
#   svols="shell admin opt data docker images temp"
#   BTRFSDATAROOT=${BTRFSDATAROOT:-/mnt/data}
#   # cd $BTRFSDATAROOT || exit
#   for svol in $svols; do
#     make_subvol $BTRFSDATAROOT/$svol $@
#   done
# }

#ssudo mount -o subvol=opt /dev/sda4 /test

snapshot_restore () {
  local src=$1
  local dest=$2
  local name=${3:-$(echo $src| rev | cut -f 2- -d '.' | rev)}
  local usesudo
  echo copying $src at $PWD to $2 then renaming to $name
  # TODO check for snapshot, strip volume from source path, remove extra snapshot when done
  [[ $EUID -ne 0 ]] && usesudo=sudo
  $usesudo $BTRFS_BIN send $src | $usesudo $BTRFS_BIN -q receive $dest
  # cd $2 || return
  $usesudo $BTRFS_BIN subvolume snapshot $dest/$src $dest/$name  
  # todo check for snapshot then delete transfered one
}



subvolume_size () {
 local all;
 [[ $1 == "-a" ]] && all=true 
 if [[ $all ]]; then 
 sudo $BTRFS_BIN qgroup show "${2:-$PWD}" --kbytes | tail -n +3
 str=$(sudo $BTRFS_BIN qgroup show "${2:-$PWD}" --kbytes | tail -n +3);
else
  sudo $BTRFS_BIN qgroup show "${2:-$PWD}" --kbytes | grep $1
  str=$(sudo $BTRFS_BIN qgroup show "${2:-$PWD}" --kbytes  | grep $1)
fi
# echo $str

subvolumeFolderSize=0;

while read line; do
  FIELDS=( $line )
  thisLineKb="${FIELDS[2]/'.00KiB'/''}";
  # echo $thisLineKb
  subvolumeFolderSize=$((subvolumeFolderSize+thisLineKb));
done <<< "$str"

[[ $all ]] && echo "size of entire filesystem at ${2:-$PWD}" || echo size of subvolumes/snapshots $1 at "${2:-$PWD}"
echo $subvolumeFolderSize KB
echo "~ $((subvolumeFolderSize/1024)) MB"
echo "~ $((subvolumeFolderSize/1024/1024)) GB"

}

# https://unix.stackexchange.com/questions/93324/how-does-this-find-command-using-find-exec-sh-c-sh-work
find_subvolumes() {
  dir=${1:-.}
  dep=${2:-1}
  sudo /bin/find "$dir" -mindepth 1 -maxdepth $dep -type d -exec bash -c '
   for d do
      subv=$(basename $d)
      sudo '$BTRFS_BIN' subvolume show "$d" >/dev/null 2>&1 && printf "%s\n" "$subv"
   done' find-sh {} +
}

folder_snapshot() {
  if [[ $1 == "-r" ]];then 
    readonly=-r
    shift 1
   else 
   readonly=""
  fi 
  for sv in $(find_subvolumes $1 1); do
    if [[ -d $2/$sv ]]; then
      echo snapshot $sv already exists in $2. You must manually delete target snapshots!
    else
      if sudo mkdir -p "$2" > /dev/null; then
      sudo $BTRFS_BIN sub snap $readonly "$1/$sv" "$2/$sv"
      else
      echo unable to make directory $2 so can not make subvolumes therein
      fi
    fi
  done

}


snapshot_send() {
  if [[ $1 == "-e" ]];then 
    dr=""
    shift 1
   else 
    echo "snapshot_send <-e> <souce snapshot path> <destination folder on different partition> <destination extension>"
    echo preface with -e to execute 
    dr="echo"
  fi
  temp="$(dirname $1)/tmp_send"
  name=$(basename $1)
  name=$(echo $name | cut -f 1 -d '.') 
  ext="$(echo $name | cut -s -f 2 -d '.')"
  [[ $ext ]] && ext=".$ext"
  [[ $3 ]] && ext=".$3" 
  sudo mkdir $temp 
  $dr sudo $BTRFS_BIN sub snap -r $1 $temp/$name$ext
  if [[ $dr ]]; then
  $dr "sudo $BTRFS_BIN send $temp/$name$ext | btrfs receive $2"
  else 
  sudo $BTRFS_BIN send $temp/$name$ext | btrfs receive $2
  fi
  $dr sudo $BTRFS_BIN sub del $temp/$name$ext
  ls -la $2
  sudo rm -r $temp
}

mount_subvolume () {
  # echo sudo mount $1 -o subvol=$2 $3
  if mountpoint $3 &> /dev/null; then
  echo $3 already a mountpoint, aborting subvolume mount
  else
  mkdir -p $3 &> /dev/null
  if ! sudo mount $1 -o subvol=$2 $3 > /dev/null ; then echo "failed to mount $2"; return 1; fi
  fi
}

named_snapshot () {
local usage; local subvol; local target; local run; local usesudo
[[ $1 == "-r" ]] && run=true && shift
[[ $EUID -ne 0 ]] && usesudo=sudo
subvol=$(realpath "$1")
usage="usage: named_snapshot <-r> <subvolume/snapshot> <new extension name> <optional target directory>"
if sudo $BTRFS_BIN subvolume show "$1" &> /dev/null; then
    # if [[ -v PS1 && ! $delete ]]; then
[[ ! $2 ]] && echo no extension name for named snapshot && echo $usage && return 1
if [[ $3 ]]; then
  [[ ! -d $3 ]] && echo "target directory $3 does not exist, can not make snapshot" && echo $usage && return 2
  target=$(realpath "$3")/$(basename "$(rm_ext "$subvol")").$2
 else 
  target="$(rm_ext "$subvol").$2"  
fi  
[[ -v PS1 && ! $run ]] && confirm "make snapshot of $subvol to $target (pass -r to avoid confirm )" || return 4  
$usesudo "$BTRFS_BIN" sub snap "$subvol" "$target"
else 
echo "$subvol not a btrfs subvolume, can't make named snapshot"
echo $usage
return 3
fi

}


# finds device and subvolume of a mountpoint (or a mountpoint above the given path)
mp_subvol () {
  module_load filesystem
  local mp; local subvol
  mp=$(find_mountpoint $1)
  path=${1//"$mp"/}
  dev=$(mount | grep "$mp " | cut -f 1 -d ' ')
  IFS=, read -r -a input <<<  $(findmnt -nt btrfs | grep "$mp ") 
  for x in "${input[@]}"; do
    eval $(echo $x | grep subvol=)
    [[ $subvol ]] && echo $dev $subvol$path
   done 
}

btrfs_clone () {
  # btrfs_clone <subvol> <source> <dest> 
  # if [[ $# == "3" ]]; then
  module_load filesystem
  local src; local dest; local dr; local usesudo
  [[ $EUID -ne 0 ]] && usesudo=sudo
  dr="--dry-run"
  [[ $1 == "-r" ]] && dr="" && shift
  subvol=$1
  src=$2
  dest=$3
  $usesudo umount /tmp/source &> /dev/null
  sudo mount $src /tmp/source
  # $usesudo umount /tmp/dest &> /dev/null
  # if mount_subvolume $src $subvol /tmp/source; then
    if ! make_subvol $dest/$(basename $subvol) &> /dev/null; then echo unable to make subvolume $1 at $dest;  return 2; fi
    # $usesudo btrfs subvolume show $dest/$(basename $subvol)
    # if mount_subvolume $(mp_subvol $dest/$(basename $subvol)) /tmp/dest; then
    #   echo cloning now
    # #  echo $usesudo btrfs-clone --toplevel $dr -v /tmp/source /tmp/dest
      cmd="$usesudo btrbk $dr archive /tmp/source/$1 $dest/$1"
      echo "command: $cmd"
      if eval "$cmd"; then
        echo "#########  $dest/$1 #########"
        ls -la /tmp/dest
        echo "#################################"
      else
        echo clone failed
        echo $cmd
      fi
    # else
    #   echo unable to mount a destination subvolume $1 at $3
    # fi
  # else
  #   echo unable to mount source subvolume $1 from $2
  #   return 1
  # fi  
  # confirm press any key to unmount temporary mountpoints /tmp/source, /tmp/dest
  echo unmounting source
  $usesudo umount /tmp/source &> /dev/null
  # $usesudo umount /tmp/dest &> /dev/null
}

# alias
alias btvl="sudo $BTRFS_BIN subvolume list"
alias btrfs="sudo $BTRFS_BIN"
alias btsub="sudo $BTRFS_BIN subvolume"







# sudo find / -type d -exec sh -c '
#    for d do
#       btrfs subvolume show "$d" >/dev/null 2>&1 && printf "%s\n" "$d"
#    done' find-sh {} +
# You may want to exclude paths that are beyond suspicion. The following code excludes /proc, /sys and /dev:

# sudo find / -type d \( \
#      \( -path /proc -prune \) -o \
#      \( -path /sys -prune \) -o \
#      \( -path /dev -prune \) -o \
#      \( -exec sh -c '
#         for d do
#            btrfs subvolume show "$d" >/dev/null 2>&1 && printf "%s\n" "$d"
#         done
#      ' find-sh {} + \) \)