return function(_, bufnr)
  -- we create a function that lets us more easily define mappings specific
  -- for LSP related items. It sets the mode, buffer and description for us each time.

  local nmap = function(keys, func, desc)
    if desc then
      desc = 'LSP: ' .. desc
    end

    vim.keymap.set('n', keys, func, { buffer = bufnr, desc = desc })
  end

  nmap('<leader>rn', vim.lsp.buf.rename, '[R]e[n]ame')
  nmap('<leader>ca', vim.lsp.buf.code_action, '[C]ode [A]ction')

  nmap('gd', vim.lsp.buf.definition, '[G]oto [D]efinition')

  -- NOTE: why are these functions that call the telescope builtin?
  -- because otherwise they would load telescope eagerly when this is defined.
  -- due to us using the on_require handler to make sure it is available.
  if nixCats('general.telescope') then
    nmap('gr', function() require('telescope.builtin').lsp_references() end, '[G]oto [R]eferences')
    nmap('gI', function() require('telescope.builtin').lsp_implementations() end, '[G]oto [I]mplementation')
    nmap('<leader>ds', function() require('telescope.builtin').lsp_document_symbols() end, '[D]ocument [S]ymbols')
    nmap('<leader>ws', function() require('telescope.builtin').lsp_dynamic_workspace_symbols() end, '[W]orkspace [S]ymbols')
  end -- TODO: someone who knows the builtin versions of these to do instead help me out please.

  nmap('<leader>D', vim.lsp.buf.type_definition, 'Type [D]efinition')

  -- See `:help K` for why this keymap
  nmap('K', vim.lsp.buf.hover, 'Hover Documentation')
  nmap('<C-k>', vim.lsp.buf.signature_help, 'Signature Documentation')

  -- Lesser used LSP functionality
  nmap('gD', vim.lsp.buf.declaration, '[G]oto [D]eclaration')
  nmap('<leader>wa', vim.lsp.buf.add_workspace_folder, '[W]orkspace [A]dd Folder')
  nmap('<leader>wr', vim.lsp.buf.remove_workspace_folder, '[W]orkspace [R]emove Folder')
  nmap('<leader>wl', function()
    print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
  end, '[W]orkspace [L]ist Folders')

  -- Create a command `:Format` local to the LSP buffer
  vim.api.nvim_buf_create_user_command(bufnr, 'Format', function(_)
    vim.lsp.buf.format()
  end, { desc = 'Format current buffer with LSP' })

end