feat(form): add form:redraw() method

Author: chenasraf

README.md

@@ -106,6 +106,37 @@ end)
 | `form:submit()`  | Gather values, close, and invoke `on_submit(results)`.                 |
 | `form:cancel()`  | Close and invoke `on_cancel()` if provided.                            |
 | `form:results()` | Return `{ [name] = value }` without closing.                           |
+| `form:redraw()`  | Tear down and re-open the form in place, preserving focus and values.  |
+
+#### `form:redraw()`
+
+Use after a callback (`on_activate`, autocommand, external code) has mutated the form — added or
+removed inputs, changed a label, swapped styling — and you want the on-screen layout to catch up.
+No-op if the form isn't currently visible.
+
+Preserved across the redraw:
+
+- Focused input index (if it's still in range; otherwise wraps).
+- Cached input values (each input flushes its current value during `unmount()` before the window is
+  destroyed, so text/multiline content is not lost).
+- The original window + editor mode captured on `:show()`, so a subsequent `:hide()` / `:cancel()` /
+  `:submit()` still restores the user's original state.
+- Help popup open/closed state.
+
+```lua
+local form
+form = require("input-form").create_form({
+  inputs = {
+    { name = "first", label = "First", type = "text" },
+    { type = "button", label = "Add field", on_activate = function(f)
+        table.insert(f._inputs, require("input-form.inputs").build({
+          name = "extra", label = "Extra", type = "text",
+        }))
+        f:redraw()
+      end },
+  },
+}):show()
+```
 
 ### Input spec reference
 

lua/input-form/form.lua

@@ -147,8 +147,14 @@ function M:show()
   -- who was in normal mode before opening the form stays in insert mode after
   -- the form closes (because the form's text inputs leave the editor in
   -- insert mode when they're focused).
-  self._prev_win = vim.api.nvim_get_current_win()
-  self._prev_mode = vim.api.nvim_get_mode().mode
+  --
+  -- Skip the capture if we already have it (e.g. `redraw()` tore the windows
+  -- down and is calling us back in), so we restore to the user's ORIGINAL
+  -- window/mode rather than to the now-torn-down form window.
+  if self._prev_mode == nil then
+    self._prev_win = vim.api.nvim_get_current_win()
+    self._prev_mode = vim.api.nvim_get_mode().mode
+  end
 
   -- Lazy: teach known UI plugins (nvim-scrollbar, satellite, ...) to skip
   -- form buffers. Runs once per nvim session.
@@ -270,11 +276,10 @@ function M:_apply_highlights()
   end
 end
 
---- Hide the form (close windows) but keep state so `:show()` can reopen it.
-function M:hide()
-  if not self._visible then
-    return
-  end
+--- Tear down every window/buffer owned by the form. Shared by `hide()` and
+--- `redraw()`. Does NOT touch `_prev_win` / `_prev_mode` — the caller decides
+--- whether to restore the editor's prior state.
+function M:_teardown_windows()
   self:_close_help()
   for _, input in ipairs(self._inputs) do
     input:unmount()
@@ -288,10 +293,45 @@ function M:hide()
   self._parent_win = nil
   self._parent_buf = nil
   self._visible = false
+end
 
+--- Hide the form (close windows) but keep state so `:show()` can reopen it.
+function M:hide()
+  if not self._visible then
+    return
+  end
+  self:_teardown_windows()
   self:_restore_editor_state()
 end
 
+--- Tear the form down and re-open it in place. Use when callbacks mutate the
+--- form (input list, labels, styles, ...) and you need the layout to catch
+--- up. No-op if the form is not currently visible.
+---
+--- Preserves: focused-input index, the captured editor state used by
+--- `:hide()`'s mode restoration, and whether the help popup was open.
+--- Cached input values survive because each input's `unmount()` flushes
+--- them onto the input object before the window goes away.
+function M:redraw()
+  if not self._visible then
+    return
+  end
+  local saved_focus = self._focus_idx
+  local help_was_open = self._help_win and vim.api.nvim_win_is_valid(self._help_win) and true
+    or false
+
+  self:_teardown_windows()
+  self:show()
+
+  -- `show()` focuses the first focusable input; put focus back where it was.
+  if saved_focus then
+    self:_focus(saved_focus)
+  end
+  if help_was_open then
+    self:_open_help()
+  end
+end
+
 --- Restore the window + mode that were active before `show()` was called.
 --- Closing the form's floating windows would otherwise leave the editor in
 --- whatever mode the focused input had it in (typically insert for text /