#!/usr/bin/env nuxr-nuxsh

nux.use nux/fs
@prefix fs nux.fs.

VFS_SOURCES_FILE=".vfs.sources"

CURRENT_SOURCES_FILE=$(nux.fs.closest "$VFS_SOURCES_FILE");

if fs:exists "$CURRENT_SOURCES_FILE" {
  CURRENT_MOUNT="${CURRENT_SOURCES_FILE%/*}";
  declare -gA CURRENT_SOURCES
  nux.log debug "Current VFS mount: ${CURRENT_MOUNT%/*}";

  while read name path; do
    CURRENT_SOURCES[${name}]="$path"
  done < "$CURRENT_SOURCES_FILE"
}

function vfs.path name {
  echo ${CURRENT_SOURCES[$name]};
}

function vfs.path.real file {
  for root in "${CURRENT_SOURCES[@]}" ; do
    nux.log trace "Testing $root$file"
    if fs:exists "${root}${file}" {
      echo ${root}${file};
      return 0;
    }
  done
}


##   list::
##     Lists all **mergerfs** based virtual filesystems managed by **vfs** tool
@command list {
  echo "1"
}

##   info::
##     Displays info about current path
@command info {
  nux.log debug "VFS mount: ${CURRENT_MOUNT}";
  echo "path:" $CURRENT_MOUNT;
  echo "sources:"
  for key in "${!CURRENT_SOURCES[@]}"; do
    echo "  $key: ${CURRENT_SOURCES[$key]}";
  done
}

##   switch:: <storage> <path+>
##     Moves specified **paths** to named **storage** for particular **vfs**.
##     This is ideal for marking files as keep or migrating them to remote,
##     rather then local.

###
###     The switch uses **.vfs.sources** file to determine location of target
###     directory and creates necessary directory structures in target directory
###     to preserve local rooted path.
###
###     FIXME: Switch does not support merging of directories


  @command switch storage {
    target="$(vfs.path "$storage")"
    if [ -z "$target" ] {
      nux.fatal "$storage does not exists."
    }
    nux.log debug "Target path $target"
    for arg_path in "$@" ; do
      rooted_path="/$(realpath -m --relative-to="$CURRENT_MOUNT" ${arg_path%/})";
      target_dir="${target}${rooted_path%/*}"
      real_file="$(vfs.path.real "$rooted_path")"
      nux.log trace "Rooted path:   $rooted_path";
      nux.log trace "Real file:     $real_file";
      nux.log trace "Target dir:    $target_dir";
      if [ -n "$real_file" ]; then
        fs:stage mkdir -p "$target_dir";
        fs:info "$arg_path" moving from "$NC_LightPurple${real_file}$NC_No" to "$NC_LightPurple$target_dir"
        fs:stage mv "$real_file" "$target_dir";
      else
        fs:error $arg_path does not exists.
      fi
    done
  }

##   mount:: <target> <name:path> [<name:path>+]
##     Mounts **mergerfs** on **target**. The mount is merge of specified pairs
##     of storage **name** and **path**.
##

@command mount target {
  local mount_paths="";
  nux.log debug "MergerFS mount: $target"

  source_tempfs="$(mktemp -d)"
  for source in "$@" ; do
    source_name="${source%%:*}"
    source_path="$(realpath "${source#*:}")"
    source_path="${source_path%/}"
    nux.log debug "  Source: $source_name Path: $source_path";
    mount_paths="$mount_paths:${source_path}"
    echo "$source_name $source_path" >> "$source_tempfs/.vfs.sources"
  done
  echo "temp $source_tempfs" >> "$source_tempfs/$VFS_SOURCES_FILE="

  mergerfs_mounts="$source_tempfs:${mount_paths}"
  nux.log debug "MergerFS command:" $mergerfs_mounts;
  mergerfs "$mergerfs_mounts" "$target"
  (cd $target; vfs info )
  }
##   unmount:: <target>
##     Unmounts target VFS filesystem.
@command :unmount target {
  fusermount -u "$target"
  fs:info "${CURRENT_SOURCES[temp]}" removing temporary metadata.
  fs:stage rm -rf "${CURRENT_SOURCES[temp]}"

}