feat: improve Telescope as action palette provider (olimorris#1195)

Author: petobens

lua/codecompanion/providers/actions/telescope.lua

@@ -2,10 +2,54 @@ local finders = require("telescope.finders")
 local pickers = require("telescope.pickers")
 local conf = require("telescope.config").values
 local action_state = require("telescope.actions.state")
+local entry_display = require("telescope.pickers.entry_display")
+local previewers = require("telescope.previewers")
 local telescope_actions = require("telescope.actions")
 
 local log = require("codecompanion.utils.log")
 
+local function wrap_text_to_table(text, max_line_length)
+  local lines = {}
+
+  for line in (text .. "\n"):gmatch("(.-)\n") do
+    local tmp_line = ""
+    for word in line:gmatch("%S+") do
+      if #tmp_line + #word + (tmp_line == "" and 0 or 1) > max_line_length then
+        table.insert(lines, tmp_line)
+        tmp_line = word
+      else
+        tmp_line = tmp_line == "" and word or tmp_line .. " " .. word
+      end
+    end
+    if tmp_line ~= "" then
+      table.insert(lines, tmp_line)
+    end
+  end
+
+  return lines
+end
+
+local action_previewer = previewers.new_buffer_previewer({
+  define_preview = function(self, entry)
+    local width = vim.api.nvim_win_get_width(self.state.winid)
+    entry.preview_command(entry, self.state.bufnr, width)
+  end,
+})
+
+local function preview_command(entry, bufnr, width)
+  vim.api.nvim_buf_call(bufnr, function()
+    local preview
+    if entry.value.prompts and entry.value.prompts[1] then
+      local content = entry.value.prompts[1].content
+      if type(content) == "string" then
+        preview = content
+      end
+    end
+    preview = preview or entry.value.description
+    vim.api.nvim_buf_set_lines(bufnr, 0, -1, true, wrap_text_to_table(preview, width))
+  end)
+end
+
 ---@class CodeCompanion.Actions.Provider.Telescope: CodeCompanion.SlashCommand.Provider
 local Provider = {}
 
@@ -22,20 +66,42 @@ end
 function Provider:picker(items, opts)
   opts = opts or {}
 
+  local max_name = 1
+  for _, item in ipairs(items) do
+    max_name = math.max(max_name, #item.name)
+  end
+
+  local displayer = entry_display.create({
+    separator = " ",
+    items = {
+      { width = max_name + 1 },
+      { remaining = true },
+    },
+  })
+
+  local function make_display(entry)
+    local columns = { entry.value.name }
+    if entry.value.strategy then
+      columns[2] = { entry.value.strategy, "Comment" }
+    end
+    return displayer(columns)
+  end
+
   return pickers
     .new(opts, {
       prompt_title = opts.prompt or "CodeCompanion actions",
       finder = finders.new_table({
         results = items,
         entry_maker = function(entry)
-          local description = entry.description and " - " .. entry.description or ""
           return {
             value = entry,
-            display = entry.name .. description,
+            display = make_display,
             ordinal = entry.name,
+            preview_command = preview_command,
           }
         end,
       }),
+      previewer = action_previewer,
       sorter = conf.generic_sorter(opts),
       attach_mappings = function(bufnr, _)
         telescope_actions.select_default:replace(function()