feat(exteionsion): recognize avante "todo" and "code" sections (#1448)

In addition to input, output, and "selected files" windows Avante may
be using a window for "todos" and a window to show a snippet of code
selected by the user. Recognize them.

Author: dtor

lua/lualine/extensions/avante.lua

@@ -1,5 +1,8 @@
 -- MIT license, see LICENSE for more details.
 -- Extension for avante.nvim
+
+local avante_ok, avante_config = pcall(require, 'avante.config')
+
 local M = {}
 
 local function ft_info()
@@ -8,13 +11,30 @@ local function ft_info()
     return 'Output'
   elseif ft == 'AvanteInput' then
     return require('lualine.utils.mode').get_mode()
+  elseif ft == 'AvanteSelectedCode' then
+    local max_shown = vim.api.nvim_win_get_height(0)
+    if avante_config.windows.sidebar_header.enabled then
+      max_shown = max_shown - 1
+    end
+    local num_lines = vim.api.nvim_buf_line_count(0)
+    return string.format('Code Fragment: %s%d lines', max_shown < num_lines and (max_shown .. '/') or '', num_lines)
   elseif ft == 'AvanteSelectedFiles' then
     return 'Total Files: ' .. vim.api.nvim_buf_line_count(0)
+  elseif ft == 'AvanteTodos' then
+    local todos = vim.api.nvim_buf_get_lines(0, 0, -1, false)
+    local completed = vim.iter(todos):fold(0, function(counter, todo)
+      if todo:sub(1, 3) == '[x]' then
+        counter = counter + 1
+      end
+      return counter
+    end)
+    return string.format('Todos: %d/%d', completed, #todos)
   end
 end
 
 M.sections = { lualine_a = { ft_info } }
 
-M.filetypes = { 'Avante', 'AvanteInput', 'AvanteSelectedFiles' }
+M.filetypes = avante_ok and { 'Avante', 'AvanteInput', 'AvanteSelectedCode', 'AvanteSelectedFiles', 'AvanteTodos' }
+  or {}
 
 return M