Using 'dropdown' preset for grep - how do I switch the position of the preview and result?

[idelice]

Using the dropdown layout, I want the preview be at the bottom and the result on the top.

How do I accomplish this?

Config

    picker = {
      formatters = {
        file = {
          filename_first = true,
          truncate = 80,
        },
      },
      sources = {
        explorer = {
          include = { "*" },
          hidden = true,
        },
        files = {
          layout = {
            preview = false,
            layout = {
              backdrop = false,
              row = 1,
              width = 0.5,
              min_width = 80,
              height = 0.5,
              border = "none",
              box = "vertical",
              { win = "input", height = 1, border = "rounded", title = "{source} {live}", title_pos = "center" },
              { win = "list", border = "hpad" },
              { win = "preview", border = "rounded" },
            },
          },
        },
        grep = {
          layout = {
            preset = "dropdown",
            fullscreen = true,
          },
        },
      },
    },

[drowning-cat]

snacks.nvim/lua/snacks/picker/config/layouts.lua

Lines 106 to 125 in bc0630e

	M.dropdown = {
	layout = {
	backdrop = false,
	row = 1,
	width = 0.4,
	min_width = 80,
	height = 0.8,
	border = "none",
	box = "vertical",
	{ win = "preview", title = "{preview}", height = 0.4, border = "rounded" },
	{
	box = "vertical",
	border = "rounded",
	title = "{title} {live} {flags}",
	title_pos = "center",
	{ win = "input", height = 1, border = "bottom" },
	{ win = "list", border = "none" },
	},
	},
	}

layout = {
  -- Base on `dropdown` layout
  -- https://github.com/folke/snacks.nvim/blob/bc0630e43be5699bb94dadc302c0d21615421d93/lua/snacks/picker/config/layouts.lua#L106-L125
  fullscreen = true,
  layout = {
    backdrop = false,
    row = 1,
    width = 0.4,
    min_width = 80,
    height = 0.8,
    border = "none",
    box = "vertical",
    {
      box = "vertical",
      border = "rounded",
      title = "{title} {live} {flags}",
      title_pos = "center",
      { win = "input", height = 1, border = "bottom" },
      { win = "list", border = "none" },
    },
    -- NOTE: Swapped
    { win = "preview", title = "{preview}", height = 0.4, border = "rounded" },
  },
},

Technically, the upper layout for sources can be a function, so you could do something like this:

layout = function()
  local layout = vim.deepcopy(require('snacks.picker.config.layouts').dropdown)
  -- Config
  layout.fullscreen = true
  -- Swap
  local preview = layout.layout[1]
  layout.layout[1] = layout.layout[2]
  layout.layout[2] = preview
  return layout
end,

But I don't recommend this approach. It might behave differently in other contexts. For example, you can’t do this kind of thing in layouts. It also hurts readability and is harder to understand. Just copy and paste like our senior grandmas used to — at least it's more maintainable.