nvt

#!/usr/bin/env zsh
setopt errexit nounset pipefail extendedglob

readonly SOCKET_DIR="${XDG_RUNTIME_DIR:-/tmp}"
readonly MAX_TTY_DEPTH=20

check_requirements() {
  local missing=0
  local required_cmds=(nvim lsof)
  
  if [[ -n "$TMUX" ]]; then
    required_cmds+=(tmux)
  fi
  
  for cmd in "${required_cmds[@]}"; do
    if ! command -v "$cmd" &> /dev/null; then
      echo "Error: Required command '$cmd' not found" >&2
      missing=1
    fi
  done
  if [[ $missing -eq 1 ]]; then
    exit 1
  fi
}

get_pipe() {
  local dir
  local servername

  if [[ -n "$TMUX" && -n "$TMUX_PANE" ]]; then
    servername="t$(tmux list-panes -t "$TMUX_PANE" -F '#S' | head -n1)"
  else
    dir="$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
    servername="s${dir//\//__}"
  fi

  echo "${SOCKET_DIR}/nvt-${servername}.pipe"
}

get_tty() {
  local pid="${1}"
  local depth="${2:-0}"

  if [[ "$pid" == "1" ]] || [[ $depth -ge $MAX_TTY_DEPTH ]]; then
    return 1
  fi

  local tty
  if ! tty=$(ps -p "$pid" -o "tty" 2>/dev/null | tail -1); then
    return 1
  fi

  tty="${tty## #}"
  tty="${tty%% #}"

  if [[ "$tty" == "??" || "$tty" == "?" ]]; then
    local ppid
    if ! ppid=$(ps -p "$pid" -o "ppid" 2>/dev/null | tail -1); then
      return 1
    fi
    ppid="${ppid## #}"
    ppid="${ppid%% #}"
    get_tty "$ppid" $((depth + 1))
    return
  fi

  echo "$tty"
}

go_to_instance() {
  if [[ -n "$TMUX" && -n "$TMUX_PANE" ]]; then
    local socket="${1}"
    local pid
    pid="$(lsof -t "$socket" 2>/dev/null | head -1)"
    if [[ -z "$pid" ]]; then
      return 0
    fi

    local tty
    if ! tty=$(get_tty "$pid" 2>/dev/null); then
      return 0
    fi

    if [[ -z "$tty" ]]; then
      return 0
    fi

    local tmux_path
    if ! tmux_path=$(tmux list-panes -s -F'#I.#P,#{pane_tty}' 2>/dev/null | grep "${tty}\$" | cut -d ',' -f1); then
      return 0
    fi

    if [[ -z "$tmux_path" ]]; then
      return 0
    fi

    tmux select-pane -t "$tmux_path" 2>/dev/null && tmux select-window -t "${tmux_path%%.*}" 2>/dev/null
  fi
  return 0
}

make_absolute() {
  local path="$1"
  [[ "$path" = /* ]] && echo "$path" || echo "$PWD/$path"
}

resolve_absolute_path() {
  local path="$1"
  local result

  if [[ -e "$path" ]]; then
    if result=$(realpath -s "$path" 2>/dev/null); then
      echo "$result"
    else
      make_absolute "$path"
    fi
  else
    make_absolute "$path"
  fi
}

is_socket_alive() {
  local socket="$1"
  [[ -e "$socket" ]] && lsof -t "$socket" &>/dev/null
}

cleanup() {
  local exit_code=$?
  if [[ $exit_code -ne 0 ]] && [[ -e "$socket" ]] && ! is_socket_alive "$socket"; then
    rm -f "$socket" 2>/dev/null
  fi
}

check_requirements

readonly socket="$(get_pipe)"

trap cleanup EXIT INT TERM

if is_socket_alive "$socket"; then
  if [[ $# -gt 0 ]]; then
    typeset -a abs_paths
    for arg in "$@"; do
      abs_paths+=("$(resolve_absolute_path "$arg")")
    done

    if ! nvim --server "$socket" --remote-silent "${abs_paths[@]}" 2>/dev/null; then
      echo "Error: Failed to send files to nvim server" >&2
      exit 1
    fi
  else
    echo "NVIM already running on $socket"
    echo "Usage: $0 <file1> [file2 ...]"
  fi

  go_to_instance "$socket"
elif [[ -e "$socket" ]]; then
  echo "Warning: Stale socket found at $socket, removing it" >&2
  rm -f "$socket"
  nvim --listen "$socket" "$@"
else
  nvim --listen "$socket" "$@"
fi