local status, cmp = pcall(require, "cmp")
if (not status) then return end


local function has_words_before()
  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

-- nvim-cmp setup
local cmp = require 'cmp'
cmp.setup {
  completion = {
    autocomplete = false
  },
  snippet = {
    expand = function(args)
      require('luasnip').lsp_expand(args.body)
    end,
  },
  mapping = {
    ['<Tab>'] = cmp.mapping(function(fallback)
          if cmp.visible() then
            cmp.select_next_item()
          elseif has_words_before() then
              cmp.complete()
          else
            fallback()
          end
        end, { "i", "s" }),
    ['<S-Tab>'] = cmp.mapping.select_prev_item(),
    ['<C-d>'] = cmp.mapping.scroll_docs(-4),
    ['<C-f>'] = cmp.mapping.scroll_docs(4),
    ['<C-e>'] = cmp.mapping.close(),
    ['<CR>'] = cmp.mapping.confirm {
      behavior = cmp.ConfirmBehavior.Replace,
      select = true,
    },
  },
  sources = {
    { name = 'nvim_lsp' },
    { name = 'luasnip' },
  },
}