nvimrc: Update completion configuration

nvimrc

@@ -68,7 +68,6 @@ set updatetime=250
 set pastetoggle=<f2>
 set pumheight=200
 " Required for nvim-compe:
-set completeopt=menu,menuone,noselect
 set complete-=i
 set nrformats-=octal
 set ttimeout
@@ -608,8 +607,12 @@ packadd! cmp-calc " https://github.com/hrsh7th/cmp-calc
 
 lua <<EOF
   local cmp = require('cmp')
+  local cmp_buffer = require('cmp_buffer')
 
   cmp.setup({
+    completion = {
+      completeopt = 'menu,menuone,noinsert',
+    },
     snippet = {
       expand = function(args)
         vim.fn["vsnip#anonymous"](args.body)
@@ -624,10 +627,22 @@ lua <<EOF
     },
     sources = cmp.config.sources({
       { name = 'nvim_lsp' },
-      { name = 'buffer' },
+      { 
+          name = 'buffer',
+          option = {
+            get_bufnrs = function()
+              return vim.api.nvim_list_bufs()
+            end
+          },
+      },
       { name = 'path' },
       { name = 'calc' },
-    })
+    }),
+    sorting = {
+      comparators = {
+        function(...) return cmp_buffer:compare_locality(...) end,
+      }
+    }
   })
 EOF