feat: experimental inline buffer chat (sudo-tee#142)

lua/opencode/ui/input_window.lua

@@ -400,10 +400,8 @@ function M.toggle()
   end
 
   if M._hidden then
-    -- Show: recreate the input window
     M._show()
   else
-    -- Hide: close the input window
     M._hide()
   end
 end
@@ -421,21 +419,18 @@ function M._hide()
   M._hidden = true
   M._toggling = true
 
-  -- Close the input window (but keep the buffer)
   pcall(vim.api.nvim_win_close, windows.input_win, false)
   windows.input_win = nil
 
-  -- Reset toggling flag after the WinClosed event has been processed
   vim.schedule(function()
     M._toggling = false
   end)
 
-  -- Focus output window
   output_window.focus_output(true)
 
   if was_at_bottom then
     vim.schedule(function()
-      require('opencode.ui.renderer').scroll_to_bottom()
+      require('opencode.ui.renderer').scroll_to_bottom(true)
     end)
   end
 end
@@ -456,15 +451,13 @@ function M._show()
   local output_window = require('opencode.ui.output_window')
   local was_at_bottom = output_window.viewport_at_bottom
 
-  -- Create a new split for the input window
   local output_win = windows.output_win
   vim.api.nvim_set_current_win(output_win)
 
   local input_position = config.ui.input_position or 'bottom'
   vim.cmd((input_position == 'top' and 'aboveleft' or 'belowright') .. ' split')
   local input_win = vim.api.nvim_get_current_win()
 
-  -- Set the buffer
   vim.api.nvim_win_set_buf(input_win, windows.input_buf)
   windows.input_win = input_win
 
@@ -478,7 +471,7 @@ function M._show()
 
   if was_at_bottom then
     vim.schedule(function()
-      require('opencode.ui.renderer').scroll_to_bottom()
+      require('opencode.ui.renderer').scroll_to_bottom(true)
     end)
   end
 end

lua/opencode/ui/renderer.lua

@@ -215,13 +215,18 @@ end
 
 ---Auto-scroll to bottom if user was already at bottom
 ---Respects cursor position if user has scrolled up
-function M.scroll_to_bottom()
+---@param force? boolean If true, scroll regardless of current position
+function M.scroll_to_bottom(force)
   if not state.windows or not state.windows.output_buf or not state.windows.output_win then
     return
   end
 
+  if not vim.api.nvim_win_is_valid(state.windows.output_win) then
+    return
+  end
+
   local ok, line_count = pcall(vim.api.nvim_buf_line_count, state.windows.output_buf)
-  if not ok then
+  if not ok or line_count == 0 then
     return
   end
 
@@ -233,18 +238,24 @@ function M.scroll_to_bottom()
   trigger_on_data_rendered()
 
   -- Determine if we should scroll to bottom
-  local should_scroll = false
-
-  -- Always scroll on initial render
-  if prev_line_count == 0 then
-    should_scroll = true
-  -- Scroll if user is at bottom (respects manual scroll position)
-  elseif output_window.viewport_at_bottom then
-    should_scroll = true
+  local should_scroll = force == true
+
+  if not should_scroll then
+    -- Always scroll on initial render
+    if prev_line_count == 0 then
+      should_scroll = true
+    -- Scroll if user is at bottom (respects manual scroll position)
+    elseif output_window.viewport_at_bottom then
+      should_scroll = true
+    end
   end
 
   if should_scroll then
     vim.api.nvim_win_set_cursor(state.windows.output_win, { line_count, 0 })
+    -- Use zb to position the cursor line at the bottom of the visible window
+    vim.api.nvim_win_call(state.windows.output_win, function()
+      vim.cmd('normal! zb')
+    end)
     output_window.viewport_at_bottom = true
   else
     -- User has scrolled up, don't scroll