tmpmv

#!/bin/bash

CONFIG_NAME=tmpmv source "$(dirname "$0")/lib/common.sh"

function show_usage() {
  msg "$script_name <cmd>"
  msg "Temporarily moves and restores files"
  msg
  msg '• list                  — lists the temporary files'
  msg '• rm <path> [...paths]  – temporarily remove a path (or multiple)'
  msg '• restore <idx>         – restore a file, specified by the same index that list showed'
  msg "• permanent-rm <idx>    — rm's the file permanently"
  msg "• cat <idx>             — cats the file's contents to stdout"
}

# takes no args; returns a list of all the temporary ids, in chronological order
function list_tmp_ids() {
  {
    for file in $(ls "$config_dir" | grep '\.link\.json$' || true); do
      local without_extension="${file%.link.json}"
      cat "$config_dir/$file" | jq -r '"\(.moved_epoch_secs) \($file)"' --arg file "$without_extension"
    done
  } | # output: "<epoch timestamp> <uuid>"
    sort --reverse --numeric-sort | # sort descending by timestamp
    cut -d ' ' -f 2 # get just the uuid
}

function do_list() {
  if [ $# -ne 0 ]; then
    err 'list does not take any arguments'
  fi
  local idx=1
  for id in $(list_tmp_ids); do
    local file="$(config_file "${id}.link.json")"
    local original_path="$(cat "$file" | jq -r '.original_path')"
    local original_time="$(cat "$file" | jq -r '.moved_epoch_secs | todateiso8601')"
    printf '%d: %s (%s)\n' "$idx" "$original_path" "$original_time"
    idx=$(( $idx + 1 ))
  done
}

function do_rm() {
  [ $# -ge 1 ] || err 'rm takes at least one argument'
  for file in "$@"; do 
    [ -e "$file" ] || { msg "No such file: $file" ; msg ; err 'No files were moved.' ; }
  done
  for file in "$@"; do
    local file_path="$(readlink -f "$file")"
    local tmp_name="$(uuidgen)"
    local tmp_json="$(config_file "$tmp_name.link.json")"
    local tmp_path="$(config_file "$tmp_name")"
    echo '{}' | jq '{original_path: $original_path, moved_epoch_secs: now}' --arg original_path "$file_path" > "$tmp_json"
    mv "$file_path" "$tmp_path"
  done
}

function list_tmp_ids_by_idx() {
  [ $# -eq 1 ] || err 'restore takes exactly one argument'
  # todo can loop if we want later, but for now this is simpler.  
  local ids="$(list_tmp_ids)"
  local idx="$1"
  echo "$idx" | grep -Eq '^[0-9]+$' || err "Invalid index (must be integer): $idx"
  if [ -z "$ids" ]; then
    # handle empty IDs as a special case, since "echo '' | wc -l" is 1 (not 0)
    err "Invalid index (out of range): $idx"
  fi
  if [ "$idx" -lt 1 ] || [ "$idx" -gt "$(echo "$ids" | wc -l)" ]; then
    err "Invalid index (out of range): $idx"
  fi
  echo "$ids" | sed -n "${idx}p" # sed: https://stackoverflow.com/a/6022441/1076640
}

function do_restore() {
  local id
  for id in $(list_tmp_ids_by_idx "$@"); do
    local link_file="$(config_file "$id.link.json")"
    local original_path="$(cat "$link_file" | jq -r '.original_path')"

    [ -e "$original_path" ] && err "Can't restore file, because there's already a file at that path: $original_path"

    mv "$(config_file "$id")" "$original_path"
    rm "$link_file"

    msg "restored $original_path"
  done
}

function do_permanent_rm() {
  local id
  for id in $(list_tmp_ids_by_idx "$@"); do
    cat "$(config_file "$id.link.json")" | jq -r '"Deleting: \(.original_path) (\(.moved_epoch_secs | todateiso8601))"' >&2
    rm -rf "$(config_file "$id")"
    rm "$(config_file "$id.link.json")"
  done
}

function do_cat() {
  local id
  for id in $(list_tmp_ids_by_idx "$@"); do
    cat "$(config_file "$id")"
  done
}

do_main() {
  if [ $# -lt 1 ]; then
    show_usage
    exit 1
  fi
  local cmd_name="$1"
  shift
  case "$cmd_name" in
    list)
      do_list "$@"
      ;;
    rm)
      do_rm "$@"
      ;;
    restore)
      do_restore "$@"
      ;;
    permanent-rm)
      do_permanent_rm "$@"
      ;;
    cat)
      do_cat "$@"
      ;;
    *)
      msg "Unrecognized command: $cmd_name"
      show_usage
      exit 1
      ;;
  esac
}

do_main "$@"