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

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

is_subvol () {
  if [[ $1 == "-r" ]]; then
    if ! btrfs subvolume show "$2" 2> /dev/null | grep readonly &> /dev/null; then return 1; fi
   else  
    btrfs subvolume show "$1" &> /dev/null
  fi  
}

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() {

    # Show usage and exit with status
    help () {
        echo 'usage: snapshot_send -h,-r <source_path, full or relative> <destination_parent_dir> <optional, alternate directory name>'
    }

    if [[ $1 == "-h" ]]; then help; return; fi

    local dr="echo " 
    if [[ $1 == "-r" ]]; then 
      unset dr; shift; 
      else
      echo this will be a dry run, use -r to actually run the command
    fi

    if [[ $# -lt 2 ]]; then  help; return 1; fi

    # Check for directories
    if ! is_subvol "$1"; then
    echo source "$1" not a subvolume
    help
    return 2
    fi  

    if [[ ! -d "$2" ]]; then
    echo destination "$2" not a valid directory
    help; return 3
    fi  

      # Get paths
  local src=$(abs_path "${1%/}")
  local psrc="$(dirname "$src")"
  local dest=$(abs_path "${2%/}")
  local snap=$(basename "$src")
  local ext="$(echo "$snap" | cut -s -f 2 -d '.')"
  local name=$(echo "$snap" | cut -f 1 -d '.') 
  [[ $ext ]] && ext=".$ext"
  [[ $3 ]] && ext=".$3" 
 
  local tsnap 
  if ! is_subvol -r "$src"; then
   tsnap=$psrc/$name.tmp 
   $dr sudo "$BTRFS_BIN" sub snap -r "$src" "$tsnap"
  fi

 if [[ $dr ]]; then
   echo "sudo $BTRFS_BIN send $([[ $tsnap ]] && echo "$tsnap" || echo "$src") | btrfs receive $dest"
   echo "sudo mv $dest/$name.tmp $dest/$name$ext"
   echo "[[ ""$tsnap"" ]] && sudo $BTRFS_BIN sub del $tsnap"
  else 
   sudo "$BTRFS_BIN" send $([[ $tsnap ]] && echo "$tsnap" || echo "$src") | btrfs receive "$dest"
   sudo mv "$dest"/"$name".tmp "$dest"/"$name"$ext
   [[ "$tsnap" ]] && sudo "$BTRFS_BIN" sub del "$tsnap"
   echo transfer is complete
   ls -la "$dest"
   ls -la "$dest"/"$name"$ext
  fi  

}

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"



dir2subvol () {
 # Directory to convert into BTRFS subvolume

dirPath="$1"

getfacl -R "$dirPath" > /tmp/_perms

# Rename original dierctory
sudo mv "${dirPath}" "${dirPath}_original"

# Create btrfs subvolume
sudo "$BTRFS_BIN" subvolume create "${dirPath}"

# Copy as "reflink" for speed and save space
sudo cp --archive --one-file-system --reflink=always \
  "${dirPath}_original/." "${dirPath}"

# Remove old directory
sudo rm -rf --one-file-system "${dirPath}_original"

setfacl --restore=/tmp/_perms 

rm -f /tmp/_perms

}



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