#!/bin/bash

# dry run by default
# >btrbk_run <conf name> <btrbk run options>
# with -e exectue
# >btrbk_run -e <conf name>  <btrbk run options>
# to only create the links
# >btrbk_run -e <conf name>  -n

# sudo -E bash -c 'source $BASH_SHELL_BASE/module.base; module_load btrbk; btrbk_run toot'


btrbk_scripts_dir="$(dirname $(realpath "${BASH_SOURCE:-$0}"))"

# will try to find a conf file with out without .conf extension in a few places
btrbk_conf () {
 local file=${1:-btrbk.conf}
 [[ -f $file ]] && echo $file && return    
 [[ -f $file.conf ]] && echo $file.conf && return   
 BTRBK_CONF_DIR=${BTRBK_CONF_DIR:-/snapshots/conf}
#  echo $btrbk_scripts_dir
#  echo $BTRBK_CONF_DIR
 [[ -f $BTRBK_CONF_DIR/$file ]] && echo $BTRBK_CONF_DIR/$file && return   
 [[ -f $BTRBK_CONF_DIR/$file.conf ]] && echo $BTRBK_CONF_DIR/$file.conf && return  
 [[ -f /etc/btrbk/$file ]] && echo  /etc/btrbk/$file && return   
 [[ -f /etc/btrbk/$file.conf ]] && echo /etc/btrbk/$file.conf && return    
 [[ -f /etc/btrbk.conf ]] && echo /etc/btrbk.conf && return  
 return 1
}

btrbk_clean () {
  local file=$(btrbk_conf $1)
  [[ ! $file ]] && return 1
  sudo btrbk -c $file clean $2
}

btrbk_src () {
  local file=$(btrbk_conf $1)
  [[ ! $file ]] && return 1
  sudo btrbk -c $file list config  --format col:h:source_subvolume
}

btrbk_dests () {
local file=$(btrbk_conf $1)
[[ ! $file ]] && return 1
local dests=$(sudo btrbk -c $file list config  --format col:h:snapshot_path | tail -1)
dests+=" $(sudo btrbk -c $file list target  --format col:h:target_path)"
echo $dests
}

btrbk_latest_links () {

local dry_run="echo"
[[ $1 == "-e" ]] && dry_run="" && shift 

local file=$(btrbk_conf $1)    
[[ ! $file ]] && echo unable to find conf file for ${1:-btrbk.conf} && return 1
shift

local latest=$(sudo btrbk -c $file list latest --format col:h:snapshot_subvolume | xargs -I % sh -c 'basename %' | sed '$!N; /^\(.*\)\n\1$/!P; D')
[[ ( ! $latest ) || $latest == "-" ]] && echo "no latest snapshots so can't make .latest links" && return 3
local dests=$(btrbk_dests $file)

if [[ $dry_run ]]; then
 echo dry run for making latest links for following destinations, NOTE: use -e to actually make them
 echo $dests
 echo "-------------------"
fi

echo making .latest symlinks in each destination 
for dest in $dests; do
for snap in $latest; do
# [[ -e $dest/${snap%%.*}.latest ]] && $dry_run_echo sudo rm $dest/${snap%%.*}.latest
local cmd="sudo ln -srfn  $dest/$snap $dest/${snap%%.*}.latest"
echo $cmd
[[ ! $dry_run ]] && $cmd
done
done

}

btrbk_run () {

local dry_run="-n"
[[ $1 == "-e" ]] && dry_run="" && shift  

local file=$(btrbk_conf $1)    
[[ ! $file ]] && echo unable to find conf file for ${1:-btrbk.conf} && return 1
shift

local src=$(btrbk_src $file)

local snaps=$(sudo btrbk -c $file list source  --format col:h:snapshot_name) 

local dests=$(sudo btrbk -c $file list config  --format col:h:snapshot_path | tail -1)
local dests+=" $(btrbk -c $file list target  --format col:h:target_path)"

# todo distinguish local from remote destinations and deal with differently for latest link

# any pre snap tasks
# for dest in $dests; do
#    if [[ ! -d $dest ]]; then
#      if confirm directory $dest does not exist, create; then
#          sudo mkdir -p $dest
#       else
#        echo destination $dest directory MUST exist aborting brtbk run
#        return 2
#      fi
#     fi 
# done

echo using configuration file: $file
echo creating snapshots: $snaps 
echo from $src
echo at these destinations $dests
echo additional passed arguments: $@

# do snaps and backups
[[ $dry_run ]] && echo backup dry run || echo Taking snapshost and making backups now...
sudo btrbk -c $file run $dry_run --progress $@

# post snap/backup

btrbk_latest_links $([[ $dry_run ]] || printf "%s" -e) $file

}

(return 0 2>/dev/null) || btrbk_run $@


latest_clone () {

   local src=$(realpath $1)
   local dest=$(realpath $2)
   shift 2
   module_load confirm
   if [[ ! -d $dest ]]; then
    if confirm "destination directory $dest does not exist, create it"; then
        sudo mkdir -p $dest
        else 
        return 1
    fi
   fi
   local snaps=$(ls $src | grep latest | sed 's/.\{1\}$//' | xargs -I % realpath $src/%)  
   [[ ! $snaps ]] && echo no latest snapshots in $src && ls -la $src && return 1
   if confirm create snapshots for $snaps in $dest; then
    local destsnap
    for snap in $snaps; do
    destsnap="$dest/$(basename $snap | cut -f 1 -d '.' )"
    if [[ -d $destsnap ]]; then
     if confirm -s snapshot $destsnap already exists do you want to over write it; then
       sudo btrfs subvolume delete $destsnap
      else
       return 2
     fi
    fi  
    sudo btrfs subvolume snapshot $@ $snap $destsnap
    done
    echo $dest  
    ls -la $dest
   fi

}

# use snapshot to then snap latest to another location, have it edit the fstab file
# #!/bin/bash
# [[ $# -lt 2 ]] && echo "need to supply a <root instance dir> and a snapshot name" && exit
# # echo sed 's/$name/'$name'/g' named.conf.tmpl  > $subvoldir-$name.conf
# # echo sed -i 's/$subvoldir/'$subvoldir'/g' $subvoldir-$name.conf 

# named="$2"
# src=/mnt/linuxpart
# dest=/mnt/linuxpart

# echo sudo mkdir -p $dest/$named
# echo sudo btrfs subvolume snapshot $src/$1/@root $dest/$named/@root
# echo sudo btrfs subvolume snapshot $src/$1/@opt $dest/$named/@opt
# echo sudo btrfs subvolume snapshot $src/$1/@home $dest/$named/@home
# echo sudo btrfs subvolume snapshot $src/@shell $dest/$named/@shell

# sudo mkdir -p $dest/$named
# sudo btrfs subvolume snapshot $src/$1/@root $dest/$named/@root
# sudo btrfs subvolume snapshot $src/$1/@opt $dest/$named/@opt
# sudo btrfs subvolume snapshot $src/$1/@home $dest/$named/@home
# sudo btrfs subvolume snapshot $src/@shell $dest/$named/@shell

# echo to edit:  bfs_vscode $dest/$named