From 31861ac4cac1db3dd53ee473f331c3c17e6d84e7 Mon Sep 17 00:00:00 2001
From: Dan Barber <github@danbarber.me>
Date: Wed, 31 May 2023 13:30:34 -0500
Subject: [PATCH] Configure LSP for Elixir

---
 .../lua/config/plugins/lspconfig/elixir.lua   |  6 +++-
 config/nvim/lua/config/plugins/nvim-cmp.lua   | 28 ++++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/config/nvim/lua/config/plugins/lspconfig/elixir.lua b/config/nvim/lua/config/plugins/lspconfig/elixir.lua
index 8251afd..d1c3482 100644
--- a/config/nvim/lua/config/plugins/lspconfig/elixir.lua
+++ b/config/nvim/lua/config/plugins/lspconfig/elixir.lua
@@ -1 +1,5 @@
-require("lspconfig").elixirls.setup({})
+local capabilities = require("cmp_nvim_lsp").default_capabilities()
+
+require("lspconfig").elixirls.setup({
+  cmd = { "elixir-ls" },
+})
diff --git a/config/nvim/lua/config/plugins/nvim-cmp.lua b/config/nvim/lua/config/plugins/nvim-cmp.lua
index 41bbca9..baf4a5e 100644
--- a/config/nvim/lua/config/plugins/nvim-cmp.lua
+++ b/config/nvim/lua/config/plugins/nvim-cmp.lua
@@ -1,3 +1,12 @@
+local has_words_before = function()
+  local line, col = unpack(vim.api.nvim_win_get_cursor(0))
+  return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
+end
+
+local feedkey = function(key, mode)
+  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(key, true, true, true), mode, true)
+end
+
 return function()
   local cmp = require("cmp")
 
@@ -16,7 +25,24 @@ return function()
       ["<C-f>"] = cmp.mapping.scroll_docs(4),
       ["<C-Space>"] = cmp.mapping.complete(),
       ["<C-e>"] = cmp.mapping.abort(),
-      ["<CR>"] = cmp.mapping.confirm({ select = true }),
+      ["<Tab>"] = cmp.mapping(function(fallback)
+        if cmp.visible() then
+          cmp.select_next_item()
+        elseif vim.fn["vsnip#available"](1) == 1 then
+          feedkey("<Plug>(vsnip-expand-or-jump)", "")
+        elseif has_words_before() then
+          cmp.complete()
+        else
+          fallback()
+        end
+      end, { "i", "s" }),
+      ["<S-Tab>"] = cmp.mapping(function()
+        if cmp.visible() then
+          cmp.select_prev_item()
+        elseif vim.fn["vsnip#jumpable"](-1) == 1 then
+          feedkey("<Plug>(vsnip-jump-prev)", "")
+        end
+      end, { "i", "s" })
     }),
     sources = cmp.config.sources({
       { name = "nvim_lsp" },