#!/usr/bin/zsh
#
# goto.zsh, a tool for bookmarking directories

function _awk {
  if command -v gawk &>/dev/null; then
    gawk "${@}"
  elif command -v awk &>/dev/null; then
    awk "${@}"
  else
    echo "Unable to find an awk!" >&2; return 1
  fi
}

function _sed {
  # MacOS support - prefer GNU sed eg. from Homebrew to 'sed'
  if command -v gsed &>/dev/null; then
    gsed "$@"
  elif command -v sed &>/dev/null; then
    sed "$@"
  else
    echo "Unable to find a sed!" >&2; return 1
  fi
}

function _goto_file {
  echo "${GOTO_FILE:-${HOME}/.labels.tsv}"
}

####################################################################################################

function goto {
  : "${1:=--help}"

  case "$1" in
    -h|--help|help)
      cat <<EOF
Usage:
  $ goto [label]

Change directory to a labeled location.
See label for label control operations
EOF
      ;;

    *)
      cd "$(label get "$1")"
      ;;
  esac
}

function _goto {
  for label in $(label ls)
  do
    compadd "$@" "${label}"
  done
}

compdef _goto goto

####################################################################################################

function label {
  : "${1:=--help}"

  case "$1" in
    -h|--help|help)
      cat <<EOF
Usage:
  $ label [add | get | rm | ls]

Set, list or manipulate configured labeles.
Note: the words 'help' and 'ls' among others are reserved, and cannot be labeled.
EOF
      ;;

    add)
      label rm "$2"
      _sed -i '' -e '$a\' `_goto_file` # Fix potentially missing last newline
      printf '%s %s\n' "${1}" $(echo "$2" | _sed "s^${HOME}^~^g") >> `_goto_file`
      ;;

    get)
      realpath "$(_awk "/^$2\s/ {print \$2;exit}" `_goto_file` | _sed "s|^~|$HOME|")"
      ;;

    rm)
      _sed -i "^$2^d" `_goto_file`
      ;;

    ls)
      _awk '{print $1;}' `_goto_file`
      ;;

    *)
      echo "Unknown command: $@" >&2
      return 1
      ;;
  esac
}

_label() {
    local line state

    _arguments -C \
               "1: :->cmds" \
               "*::arg:->args"
    case "$state" in
        cmds)
            _values "label command" \
                    "add[Create or overwrite a label.]" \
                    "ls[List existing labels.]" \
                    "get[Fetch the location of a label.]" \
                    "rm[Delete a label.]"
            ;;
        args)
            case "$line[1]" in
                rm|get)
                  _labels
                  ;;
            esac
            ;;
    esac
}

compdef _label label