feat: layout actions (#1383)

Co-authored-by: johnybx <johnybx@users.noreply.github.com>

4 files changed, 171 insertions, 34 deletions

diff --git a/lua/telescope/actions/layout.lua b/lua/telescope/actions/layout.lua
new file mode 100644
index 0000000..f40151f
--- /dev/null
+++ b/lua/telescope/actions/layout.lua
@@ -0,0 +1,140 @@
+---@tag telescope.actions.layout
+
+---@brief [[
+--- The layout actions are actions to be used to change the layout of a picker.
+---@brief ]]
+
+local action_state = require "telescope.actions.state"
+local state = require "telescope.state"
+local layout_strats = require "telescope.pickers.layout_strategies"
+
+local action_layout = {}
+
+--- Toggle preview window.
+--- - Note: preview window can be toggled even if preview is set to false.
+---
+--- This action is not mapped by default.
+---@param prompt_bufnr number: The prompt bufnr
+action_layout.toggle_preview = function(prompt_bufnr)
+  local picker = action_state.get_current_picker(prompt_bufnr)
+  local status = state.get_status(picker.prompt_bufnr)
+
+  if picker.previewer and status.preview_win then
+    picker.hidden_previewer = picker.previewer
+    picker.previewer = nil
+  elseif picker.hidden_previewer and not status.preview_win then
+    picker.previewer = picker.hidden_previewer
+    picker.hidden_previewer = nil
+  else
+    return
+  end
+  picker:full_layout_update()
+end
+
+-- TODO IMPLEMENT (mentored project available, contact @l-kershaw)
+action_layout.toggle_padding = function(prompt_bufnr)
+  local picker = action_state.get_current_picker(prompt_bufnr)
+  -- if padding ~= 0
+  --    1. Save `height` and `width` of picker
+  --    2. Set both to `{padding = 0}`
+  -- else
+  --    1. Lookup previous `height` and `width` of picker
+  --    2. Set both to previous values
+  picker:full_layout_update()
+end
+
+--- Toggles the `prompt_position` option between "top" and "bottom".
+--- Checks if `prompt_position` is an option for the current layout.
+---
+--- This action is not mapped by default.
+---@param prompt_bufnr number: The prompt bufnr
+action_layout.toggle_prompt_position = function(prompt_bufnr)
+  local picker = action_state.get_current_picker(prompt_bufnr)
+  picker.layout_config = picker.layout_config or {}
+  picker.layout_config[picker.layout_strategy] = picker.layout_config[picker.layout_strategy] or {}
+  -- flex layout is weird and needs handling separately
+  if picker.layout_strategy == "flex" then
+    picker.layout_config.flex.horizontal = picker.layout_config.flex.horizontal or {}
+    picker.layout_config.flex.vertical = picker.layout_config.flex.vertical or {}
+    local old_pos = picker.layout_config.flex[picker.__flex_strategy].prompt_position
+    local new_pos = old_pos == "top" and "bottom" or "top"
+    picker.layout_config[picker.__flex_strategy].prompt_position = new_pos
+    picker.layout_config.flex[picker.__flex_strategy].prompt_position = new_pos
+    picker:full_layout_update()
+  elseif layout_strats._configurations[picker.layout_strategy].prompt_position then
+    if picker.layout_config.prompt_position == "top" then
+      picker.layout_config.prompt_position = "bottom"
+      picker.layout_config[picker.layout_strategy].prompt_position = "bottom"
+    else
+      picker.layout_config.prompt_position = "top"
+      picker.layout_config[picker.layout_strategy].prompt_position = "top"
+    end
+    picker:full_layout_update()
+  end
+end
+
+--- Toggles the `mirror` option between `true` and `false`.
+--- Checks if `mirror` is an option for the current layout.
+---
+--- This action is not mapped by default.
+---@param prompt_bufnr number: The prompt bufnr
+action_layout.toggle_mirror = function(prompt_bufnr)
+  local picker = action_state.get_current_picker(prompt_bufnr)
+  -- flex layout is weird and needs handling separately
+  if picker.layout_strategy == "flex" then
+    picker.layout_config.flex.horizontal = picker.layout_config.flex.horizontal or {}
+    picker.layout_config.flex.vertical = picker.layout_config.flex.vertical or {}
+    local new_mirror = not picker.layout_config.flex[picker.__flex_strategy].mirror
+    picker.layout_config[picker.__flex_strategy].mirror = new_mirror
+    picker.layout_config.flex[picker.__flex_strategy].mirror = new_mirror
+    picker:full_layout_update()
+  elseif layout_strats._configurations[picker.layout_strategy].mirror then
+    picker.layout_config = picker.layout_config or {}
+    local new_mirror = not picker.layout_config.mirror
+    picker.layout_config.mirror = new_mirror
+    picker.layout_config[picker.layout_strategy] = picker.layout_config[picker.layout_strategy] or {}
+    picker.layout_config[picker.layout_strategy].mirror = new_mirror
+    picker:full_layout_update()
+  end
+end
+
+-- Helper function for `cycle_layout_next` and `cycle_layout_prev`.
+local get_cycle_layout = function(dir)
+  return function(prompt_bufnr)
+    local picker = action_state.get_current_picker(prompt_bufnr)
+    if picker.__layout_index then
+      picker.__layout_index = ((picker.__layout_index + dir - 1) % #picker.__cycle_layout_list) + 1
+    else
+      picker.__layout_index = 1
+    end
+    local new_layout = picker.__cycle_layout_list[picker.__layout_index]
+    if type(new_layout) == "string" then
+      picker.layout_strategy = new_layout
+      picker.layout_config = nil
+      picker.previewer = picker.all_previewers and picker.all_previewers[1] or nil
+    elseif type(new_layout) == "table" then
+      picker.layout_strategy = new_layout.layout_strategy
+      picker.layout_config = new_layout.layout_config
+      picker.previewer = (new_layout.previewer == nil and picker.all_previewers[picker.current_previewer_index])
+        or new_layout.previewer
+    else
+      error("Not a valid layout setup: " .. vim.inspect(new_layout) .. "\nShould be a string or a table")
+    end
+
+    picker:full_layout_update()
+  end
+end
+
+--- Cycles to the next layout in `cycle_layout_list`.
+---
+--- This action is not mapped by default.
+---@param prompt_bufnr number: The prompt bufnr
+action_layout.cycle_layout_next = get_cycle_layout(1)
+
+--- Cycles to the previous layout in `cycle_layout_list`.
+---
+--- This action is not mapped by default.
+---@param prompt_bufnr number: The prompt bufnr
+action_layout.cycle_layout_prev = get_cycle_layout(-1)
+
+return action_layout
diff --git a/lua/telescope/config.lua b/lua/telescope/config.lua
index 127307b..a96bc0b 100644
--- a/lua/telescope/config.lua
+++ b/lua/telescope/config.lua
@@ -190,6 +190,23 @@ append(
 append("layout_config", layout_config_defaults, layout_config_description)
 
 append(
+  "cycle_layout_list",
+  { "horizontal", "vertical", { layout_strategy = "horizontal", previewer = false } },
+  [[
+  Determines the layouts to cycle through when using `actions.cycle_layout_next`
+  and `actions.cycle_layout_prev`.
+  Should be a list of "layout setups".
+  Each "layout setup" can take one of two forms:
+  1. string <br>
+      This is interpreted as the name of a `layout_strategy`
+  2. table <br>
+      A table with possible keys `layout_strategy`, `layout_config` and `previewer`
+
+  Default: TODO
+  ]]
+)
+
+append(
   "winblend",
   0,
   [[
diff --git a/lua/telescope/pickers.lua b/lua/telescope/pickers.lua
index 76e6136..b626c46 100644
--- a/lua/telescope/pickers.lua
+++ b/lua/telescope/pickers.lua
@@ -104,6 +104,8 @@ function Picker:new(opts)
     layout_strategy = layout_strategy,
     layout_config = config.smarter_depth_2_extend(opts.layout_config or {}, config.values.layout_config or {}),
 
+    __cycle_layout_list = get_default(opts.cycle_layout_list, config.values.cycle_layout_list),
+
     window = {
       winblend = get_default(
         opts.winblend,
@@ -330,6 +332,7 @@ function Picker:find()
   end
 
   local results_win, results_opts, results_border_win = self:_create_window("", popup_opts.results, true)
+
   local results_bufnr = a.nvim_win_get_buf(results_win)
 
   self.results_bufnr = results_bufnr
@@ -572,9 +575,9 @@ function Picker:recalculate_layout()
   -- self.max_results = popup_opts.results.height
 end
 
-local update_scroll = function(win, oldinfo, oldcursor, strategy, max_results)
+local update_scroll = function(win, oldinfo, oldcursor, strategy, buf_maxline)
   if strategy == "ascending" then
-    vim.api.nvim_win_set_cursor(win, { max_results, 0 })
+    vim.api.nvim_win_set_cursor(win, { buf_maxline, 0 })
     vim.api.nvim_win_set_cursor(win, { oldinfo.topline, 0 })
     vim.api.nvim_win_set_cursor(win, oldcursor)
   elseif strategy == "descending" then
@@ -586,34 +589,15 @@ local update_scroll = function(win, oldinfo, oldcursor, strategy, max_results)
   end
 end
 
-function Picker:toggle_preview()
-  local status = state.get_status(self.prompt_bufnr)
-
-  if self.previewer and status.preview_win then
-    self.hidden_previewer = self.previewer
-    self.previewer = nil
-  elseif self.hidden_previewer and not status.preview_win then
-    self.previewer = self.hidden_previewer
-    self.hidden_previewer = nil
-  else
-    return
-  end
-
-  local oldinfo = vim.fn.getwininfo(status.results_win)[1]
-  local oldcursor = vim.api.nvim_win_get_cursor(status.results_win)
-
+function Picker:full_layout_update()
+  local oldinfo = vim.fn.getwininfo(self.results_win)[1]
+  local oldcursor = vim.api.nvim_win_get_cursor(self.results_win)
   self:recalculate_layout()
   self:refresh_previewer()
-  update_scroll(status.results_win, oldinfo, oldcursor, self.sorting_strategy, self.max_results)
-end
 
-function Picker:toggle_padding()
-  -- if padding ~= 0
-  --    1. Save `height` and `width` of picker
-  --    2. Set both to `{padding = 0}`
-  -- else
-  --    1. Lookup previous `height` and `width` of picker
-  --    2. Set both to previous values
+  -- update scrolled position
+  local buf_maxline = #vim.api.nvim_buf_get_lines(self.results_bufnr, 0, -1, false)
+  update_scroll(self.results_win, oldinfo, oldcursor, self.sorting_strategy, buf_maxline)
 end
 
 -- TODO: update multi-select with the correct tag name when available
@@ -1310,13 +1294,7 @@ function pickers.on_resize_window(prompt_bufnr)
   local status = state.get_status(prompt_bufnr)
   local picker = status.picker
 
-  local oldinfo = vim.fn.getwininfo(status.results_win)[1]
-  local oldcursor = vim.api.nvim_win_get_cursor(status.results_win)
-  picker:recalculate_layout()
-  picker:refresh_previewer()
-
-  -- update scrolled position
-  update_scroll(status.results_win, oldinfo, oldcursor, picker.sorting_strategy, picker.max_results)
+  picker:full_layout_update()
 end
 
 --- Get the prompt text without the prompt prefix.
diff --git a/lua/telescope/pickers/layout_strategies.lua b/lua/telescope/pickers/layout_strategies.lua
index 411b7fc..271fc72 100644
--- a/lua/telescope/pickers/layout_strategies.lua
+++ b/lua/telescope/pickers/layout_strategies.lua
@@ -707,8 +707,10 @@ layout_strategies.flex = make_documented_layout(
     local flip_lines = if_nil(layout_config.flip_lines, 20)
 
     if max_columns < flip_columns and max_lines > flip_lines then
+      self.__flex_strategy = "vertical"
       return layout_strategies.vertical(self, max_columns, max_lines, layout_config.vertical)
     else
+      self.__flex_strategy = "horizontal"
       return layout_strategies.horizontal(self, max_columns, max_lines, layout_config.horizontal)
     end
   end