feat(picker): allow showing the preview in the main buffer

lua/snacks/picker/config/defaults.lua

@@ -44,7 +44,7 @@ local M = {}
 ---@field reverse? boolean when true, the list will be reversed (bottom-up)
 ---@field fullscreen? boolean open in fullscreen
 ---@field cycle? boolean cycle through the list
----@field preview? boolean show preview window
+---@field preview? boolean|"main" show preview window in the picker or the main window
 ---@field preset? string|fun(source:string):string
 
 ---@class snacks.picker.win.Config

lua/snacks/picker/core/actions.lua

@@ -17,6 +17,9 @@ function M.get(picker)
     ---@param t table<string, snacks.win.Action>
     ---@param k string
     __index = function(t, k)
+      if type(k) ~= "string" then
+        return
+      end
       local p = ref()
       if not p then
         return

lua/snacks/picker/core/picker.lua

@@ -82,9 +82,11 @@ function M.new(opts)
   M._pickers[self] = true
   M._active[self] = true
 
+  local layout = Snacks.picker.config.layout(self.opts)
   self.list = require("snacks.picker.core.list").new(self)
   self.input = require("snacks.picker.core.input").new(self)
-  self.preview = require("snacks.picker.core.preview").new(self.opts)
+  self.preview =
+    require("snacks.picker.core.preview").new(self.opts, layout.preview == "main" and self.parent_win or nil)
 
   M.last = {
     opts = self.opts,
@@ -109,11 +111,10 @@ function M.new(opts)
     end
   end)
 
-  self:init_layout()
+  self:init_layout(layout)
   self.input.win:on("VimResized", function()
     vim.schedule(function()
-      local layout = Snacks.picker.config.layout(self.opts)
-      self:set_layout(layout)
+      self:set_layout(Snacks.picker.config.layout(self.opts))
     end)
   end)
 
@@ -132,6 +133,12 @@ function M:init_layout(layout)
   layout = layout or Snacks.picker.config.layout(self.opts)
   self.resolved_layout = vim.deepcopy(layout)
   local opts = layout --[[@as snacks.layout.Config]]
+  local preview_main = layout.preview == "main"
+  local preview_hidden = layout.preview == false or preview_main
+  local backdrop = nil
+  if preview_main then
+    backdrop = false
+  end
   self.layout = Snacks.layout.new(vim.tbl_deep_extend("force", opts, {
     win = {
       wo = {
@@ -141,13 +148,17 @@ function M:init_layout(layout)
     wins = {
       input = self.input.win,
       list = self.list.win,
-      preview = self.preview.win,
+      preview = not preview_main and self.preview.win or nil,
     },
-    hidden = { layout.preview == false and "preview" or nil },
+    hidden = { preview_hidden and "preview" or nil },
     on_update = function()
       self:update_titles()
     end,
+    layout = {
+      backdrop = backdrop,
+    },
   }))
+  self.preview:update(preview_main and self.parent_win or nil)
   -- apply box highlight groups
   local boxwhl = Snacks.picker.highlight.winhl("SnacksPickerBox")
   for _, win in pairs(self.layout.box_wins) do
@@ -246,6 +257,9 @@ function M:show()
   end
   self.shown = true
   self.layout:show()
+  if self.preview.main then
+    self.preview.win:show()
+  end
   self.input.win:focus()
 end
 
@@ -290,6 +304,7 @@ function M:close()
   if (current == self.input.win.win or current == self.list.win.win) and vim.api.nvim_win_is_valid(self.parent_win) then
     vim.api.nvim_set_current_win(self.parent_win)
   end
+  self.preview.win:close()
   self.layout:close()
   self.updater:stop()
   M._active[self] = nil

lua/snacks/picker/core/preview.lua

@@ -3,6 +3,8 @@
 ---@field win snacks.win
 ---@field previewer snacks.picker.Previewer
 ---@field state table<string, any>
+---@field main? number
+---@field win_opts {main: snacks.win.Config, layout: snacks.win.Config, win: snacks.win.Config}
 local M = {}
 M.__index = M
 
@@ -18,26 +20,45 @@ local ns = vim.api.nvim_create_namespace("snacks.picker.preview")
 local ns_loc = vim.api.nvim_create_namespace("snacks.picker.preview.loc")
 
 ---@param opts snacks.picker.Config
-function M.new(opts)
+---@param main? number
+function M.new(opts, main)
   local self = setmetatable({}, M)
-  self.win = Snacks.win(Snacks.win.resolve(
+  local win_opts = Snacks.win.resolve(
     {
       title_pos = "center",
     },
     opts.win.preview,
     {
       show = false,
+      enter = false,
+      width = 0,
+      height = 0,
       fixbuf = false,
-      wo = {
-        winhighlight = Snacks.picker.highlight.winhl("SnacksPickerPreview"),
-      },
       bo = { filetype = "snacks_picker_preview" },
       on_win = function()
         self.item = nil
         self:reset()
       end,
     }
-  ))
+  )
+  self.win_opts = {
+    main = {
+      relative = "win",
+      backdrop = false,
+      wo = {
+        winhighlight = "NormalFloat:Normal",
+      },
+    },
+    layout = {
+      backdrop = win_opts.backdrop == true,
+      relative = "win",
+      wo = {
+        winhighlight = Snacks.picker.highlight.winhl("SnacksPickerPreview"),
+      },
+    },
+  }
+  self.win = Snacks.win(win_opts)
+  self:update(main)
   self.state = {}
 
   self.win:on("WinClosed", function()
@@ -51,6 +72,16 @@ function M.new(opts)
   return self
 end
 
+---@param main? number
+function M:update(main)
+  self.main = main
+  self.win_opts.main.win = main
+  self.win.opts = vim.tbl_deep_extend("force", self.win.opts, main and self.win_opts.main or self.win_opts.layout)
+  if self.win:valid() then
+    self.win:update()
+  end
+end
+
 ---@param picker snacks.Picker
 function M:preview(picker)
   local item = picker:current()

lua/snacks/win.lua

@@ -522,6 +522,9 @@ end
 ---@param title string
 ---@param pos? "center"|"left"|"right"
 function M:set_title(title, pos)
+  if not self:has_border() then
+    return
+  end
   title = vim.trim(title)
   if title ~= "" then
     -- HACK: add extra space when last char is non word