.dotfiles/nvim/lua/autocompletion.lua

-- Setup nvim-cmp.
local cmp = require 'cmp'

cmp.setup({
  snippet = {
    expand = function(args)
      require('luasnip').lsp_expand(args.body)
    end,
  },
  mapping = {
    ['<C-b>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
    ['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
    ['<C-n>'] = cmp.mapping(cmp.mapping.select_next_item(), {'i','c'}),
    ['<C-p>'] = cmp.mapping(cmp.mapping.select_prev_item(), {'i','c'}),
    ['<C-Space>'] = cmp.mapping(cmp.mapping.complete(), { 'i', 'c' }),
    ['<C-y>'] = cmp.config.disable, -- Specify `cmp.config.disable` if you want to remove the default `<C-y>` mapping.
    ['<C-e>'] = cmp.mapping({
      i = cmp.mapping.abort(),
      c = cmp.mapping.close(),
    }),
    -- Accept currently selected item. If none selected, `select` first item.
    -- Set `select` to `false` to only confirm explicitly selected items.
    ['<CR>'] = cmp.mapping.confirm({ select = true }),
  },
  sources = cmp.config.sources({
    { name = 'nvim_lsp' },
    { name = 'luasnip' },
  }, {
    { name = 'buffer' },
  })
})

-- Use buffer source for `/`
cmp.setup.cmdline('/', {
  sources = {
    { name = 'buffer' }
  }
})

-- Use cmdline & path source for ':'
cmp.setup.cmdline(':', {
  sources = cmp.config.sources({
    { name = 'path' }
  }, {
    { name = 'cmdline' }
  })
})

local on_attach = function(client, bufnr)
  local function buf_set_keymap(...)
    vim.api.nvim_buf_set_keymap(bufnr, ...)
  end

  local opts = { noremap = true, silent = true }
  buf_set_keymap("n", "gd", "<cmd>Telescope lsp_definitions<CR>", opts)
  buf_set_keymap("n", "gh", "<cmd>lua vim.lsp.buf.hover()<CR>", opts)
  buf_set_keymap("n", "gD", "<cmd>Telescope lsp_implementations<CR>", opts)
  buf_set_keymap("n", "gs", "<cmd>lua vim.lsp.buf.signature_help()<CR>", opts)
  buf_set_keymap("n", "gR", "<cmd>lua vim.lsp.buf.rename()<CR>", opts)
  buf_set_keymap("n", "gH", "<cmd>Telescope lsp_code_actions<CR>", opts)
  buf_set_keymap("n", "gr", "<cmd>Telescope lsp_references<CR>", opts)
  buf_set_keymap("n", "ge", "<cmd>lua vim.diagnostic.open_float()<CR>", opts)
end

local lsp_installer = require 'nvim-lsp-installer'
lsp_installer.on_server_ready(function(server)
  local opts = {}
  opts.on_attach = on_attach
  opts.capabilities = require('cmp_nvim_lsp').update_capabilities(vim.lsp.protocol.make_client_capabilities())

  server:setup(opts)
  vim.cmd [[ do User LspAttachBuffers ]]
end)