From 6a1810f4dfe4ac22dfbaf2b98fb7618fd76eb761 Mon Sep 17 00:00:00 2001
From: Robert Günzler <r@gnzler.io>
Date: Wed, 30 Apr 2025 13:14:22 +0200
Subject: vim: misc updates
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Robert Günzler <r@gnzler.io>
---
 .vim/plugin/syncbg.lua | 90 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 55 insertions(+), 35 deletions(-)

(limited to '.vim/plugin/syncbg.lua')

diff --git a/.vim/plugin/syncbg.lua b/.vim/plugin/syncbg.lua
index d9243f0..c11bef6 100644
--- a/.vim/plugin/syncbg.lua
+++ b/.vim/plugin/syncbg.lua
@@ -1,53 +1,73 @@
--- this plugin registers two autocmds that trigger when openeing and closing vim, setting the
+-- this plugin registers two autocmds that trigger when openeing and closing the editor, setting the
 -- background of the terminal to the color used by our colorscheme using CSI control codes.
 
-local state = {}
+local state = { enabled = false }
 
--- get tty
-local tty_handle = io.popen('tty')
-if tty_handle == nil then
+if not state.enabled then
   return
 end
-local tty = tty_handle:read('*a')
-tty_handle:close()
-if tty:find('not a tty') then
-  error('not a tty')
+
+local set_bg = function(clear)
+  if not (state.tty and state.normal) then
+    return
+  end
+  if clear then
+    -- emit CSI to unset custom background
+    os.execute('printf "\\033]111\\007" > ' .. state.tty)
+  else
+    -- emit CSI to change terminal background to Normal.bg
+    os.execute(
+      'printf "\\033]11;' .. string.format('#%06x', state.normal.bg) .. '\\007" > ' .. state.tty
+    )
+    -- set colorscheme Normal.bg to NONE, making it transparent
+    vim.cmd([[hi Normal ctermbg=NONE guibg=NONE]])
+  end
 end
-state.tty = tty
 
--- register update hook
-vim.api.nvim_create_autocmd({ 'ColorScheme', 'UIEnter', 'VimResume' }, {
-  callback = function()
-    if state.tty == nil then
+local discover = function()
+  if not state.tty then
+    -- get tty handle
+    local ok, tty_handle = pcall(io.popen, 'tty')
+    if (not ok) or tty_handle == nil then
       return
     end
+    local tty = tty_handle:read('*l')
+    tty_handle:close()
+    if tty:find('not a tty') then
+      return
+    end
+    state.tty = tty
+  end
 
-    if not state.normal then
-      -- get colorscheme Normal highlight
-      local normal = vim.api.nvim_get_hl(0, { name = 'Normal', create = false })
-      if normal.bg == nil then
-        return
-      end
-      -- cache old value for use with VimResume
-      state.normal = normal
+  if not state.normal then
+    -- get colorscheme Normal highlight
+    local normal = vim.api.nvim_get_hl(0, { name = 'Normal', create = false })
+    if normal.bg == nil then
+      return
     end
+    -- cache old value for use with VimResume
+    state.normal = normal
+  end
 
-    -- emit CSI to change terminal background to Normal.bg
-    os.execute(
-      'printf "\\033]11;' .. string.format('#%06x', state.normal.bg) .. '\\007" > ' .. state.tty
-    )
+  -- vim.notify('syncbg: ' .. vim.inspect(state), vim.log.levels.DEBUG)
+end
 
-    -- set colorscheme Normal.bg to NONE, making it transparent
-    vim.cmd([[hi Normal ctermbg=NONE guibg=NONE]])
-  end,
+-- setup autogroup
+local aug = vim.api.nvim_create_augroup('syncbg', { clear = true })
+
+-- register update hook
+vim.api.nvim_create_autocmd({ 'ColorScheme', 'UIEnter', 'VimResume' }, {
+  group = aug,
+  callback = vim.schedule_wrap(function()
+    discover()
+    set_bg(false)
+  end),
 })
 
 -- register reset hook
 vim.api.nvim_create_autocmd({ 'UILeave' }, {
-  callback = function()
-    if state.tty == nil then
-      return
-    end
-    os.execute('printf "\\033]111\\007" > ' .. state.tty)
-  end,
+  group = aug,
+  callback = vim.schedule_wrap(function()
+    set_bg(true)
+  end),
 })
-- 
cgit 1.4.1