fix: refactor buffer manager (#1666)

* chore: remove useless code and improve
integration notes

* chore: Remove unnecessary comments as the code is already self-explanatory

* chore: optional chaining, ternary

* refactor: Merge the logic for handling activeEditor and visibleEditors

Theoretically, there is an improvement for some edge cases

* fix: check if the buffer is valid when setting options

* refactor: cleanupWindowAndBuffers

* chore: await updateNeovimCursorPosition

* chore: simplify code

* chore: remove unused code

* fix: should await the client.window

* chore: Re-add comments about editor options

* refactor: read fallback editor options from settings

runtime/lua/vscode-neovim/sync-options.lua

@@ -45,6 +45,11 @@ end
 ---@param buf number
 ---@param opts EditorOptions
 local function set_options(buf, opts)
+  -- Due to debounce of editor options change event, in some special cases, buffer
+  -- may be deleted when starting to set options.
+  if not api.nvim_buf_is_valid(buf) then
+    return
+  end
   api.nvim_buf_set_var(buf, "vscode_editor_options", opts)
   if vim.bo[buf].ts ~= opts.tabSize then
     vim.bo[buf].ts = opts.tabSize
@@ -127,6 +132,9 @@ end
 function M.setup()
   vscode.on("editor_options_changed", set_options)
   vscode.on("document_buffer_init", function(buf)
+    if not api.nvim_buf_is_valid(buf) then
+      return
+    end
     local has, opts = pcall(api.nvim_buf_get_var, buf, "vscode_editor_options")
     if has then
       set_options(buf, opts)