local has_words_before = function()
  unpack = unpack or table.unpack
  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 cmp = require 'cmp'

cmp.setup({
  snippet = {
    -- REQUIRED - you must specify a snippet engine
    expand = function(args)
      vim.fn["vsnip#anonymous"](args.body)     -- For `vsnip` users.
      -- require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
      -- require('snippy').expand_snippet(args.body) -- For `snippy` users.
      -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
    end,
  },
  window = {
    -- completion = cmp.config.window.bordered(),
    -- documentation = cmp.config.window.bordered(),
  },
  mapping = cmp.mapping.preset.insert({
    ['<C-Space>'] = cmp.mapping.confirm {
      behavior = cmp.ConfirmBehavior.Insert,
      select = true,
    },

    ['<Tab>'] = function(fallback)
      if not cmp.select_next_item() then
        if vim.bo.buftype ~= 'prompt' and has_words_before() then
          cmp.complete()
        else
          fallback()
        end
      end
    end,

    ['<S-Tab>'] = function(fallback)
      if not cmp.select_prev_item() then
        if vim.bo.buftype ~= 'prompt' and has_words_before() then
          cmp.complete()
        else
          fallback()
        end
      end
    end,
  }),
  sources = cmp.config.sources({
    { name = 'nvim_lsp' },
    { name = 'vsnip' },     -- For vsnip users.
    -- { name = 'luasnip' }, -- For luasnip users.
    -- { name = 'ultisnips' }, -- For ultisnips users.
    -- { name = 'snippy' }, -- For snippy users.
  }, {
    { name = 'buffer' },
  })
})

-- Set configuration for specific filetype.
cmp.setup.filetype('gitcommit', {
  sources = cmp.config.sources({
    { name = 'cmp_git' },     -- You can specify the `cmp_git` source if you were installed it.
  }, {
    { name = 'buffer' },
  })
})

-- Use buffer source for `/` and `?` (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline({ '/', '?' }, {
  mapping = cmp.mapping.preset.cmdline(),
  sources = {
    { name = 'buffer' }
  }
})

-- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline(':', {
  mapping = cmp.mapping.preset.cmdline(),
  sources = cmp.config.sources({
    { name = 'path' }
  }, {
    { name = 'cmdline' }
  })
})

-- Set up lspconfig.
local capabilities = require('cmp_nvim_lsp').default_capabilities()
-- Replace <YOUR_LSP_SERVER> with each lsp server you've enabled.
require('lspconfig')['pyright'].setup {
  capabilities = capabilities
}