nix/home-manager/common/software/cli/nixvim/cmp.nix

{ ... }: {
  programs.nixvim.plugins = {
    # Snippet engine for neovim
    luasnip.enable = true;
    cmp_luasnip.enable = true;
    # CMP  Addons
    cmp-buffer.enable = true;
    cmp-path.enable = true;
    cmp-nvim-lsp.enable = true;
    cmp-nvim-lsp-document-symbol.enable = true;
    cmp-nvim-lsp-signature-help.enable = true;

    nvim-cmp = {
      enable = true;
      autoEnableSources = true;
      mapping = {
        "<C-Space>" = "cmp.mapping.complete()";
        "<C-d>" = "cmp.mapping.scroll_docs(-4)";
        "<C-e>" = "cmp.mapping.close()";
        "<C-f>" = "cmp.mapping.scroll_docs(4)";
        "<CR>"  = "cmp.mapping.confirm({ select = true })";
        "<S-Tab>" = {
          action = "cmp.mapping.select_prev_item()";
          modes = [
          "i"
          "s"
          ];
        };
        "<Tab>" = {
          action = "cmp.mapping.select_next_item()";
          modes = [
          "i"
          "s"
          ];
        };
      };
      sources = [
        { name = "nvim_lua"; }
        { name = "nvim_lsp"; }
#        { name = "nvim_lsp_signature_help"; }
        { name = "calc"; }
        { name = "path"; }
        { name = "buffer"; }
        { name = "luasnip"; }
      ];
        snippet.expand = "luasnip";
        window = {
          completion.border = "rounded"; 
          documentation.border = "rounded";
        };
        formatting = {
          fields = [ "menu" "abbr" "kind" ];
          # https://rsdlt.github.io/posts/rust-nvim-ide-guide-walkthrough-development-debug/
          format = ''
            function(entry, item)
              local menu_icon = {
                nvim_lsp = 'λ',
                luasnip = '⋗',
                buffer = 'Ω',
                path = '🖫',
              }
              item.menu = menu_icon[entry.source.name]
              return item
            end,
          '';
      };
    };
  };
}