local function toggle_todo()
  local ln, n = vim.api.nvim_get_current_line(), 0
  ln, n = string.gsub(ln, 'TODO', 'DONE', 1)
  if n > 0 then
    goto set_line
  end
  ln, n = string.gsub(ln, 'DONE', 'TODO', 1)
  if n > 0 then
    goto set_line
  end
  ln, n = string.gsub(ln, '^(-|*) ', '%1 TODO ')
  if n > 0 then
    goto set_line
  end

  goto exit -- skip over set_current_line

  ::set_line::
  vim.api.nvim_set_current_line(ln)

  ::exit::
end
vim.keymap.set('n', '<space><space>', toggle_todo, { desc = 'toggle todo', buffer = true })