treesitter.nix

{ pkgs
, config
, lib
, ...
}:
with lib;
with builtins; let
  cfg = config.vim.treesitter;
  usingNvimCmp = config.vim.autocomplete.enable && config.vim.autocomplete.type == "nvim-cmp";
in
{
  options.vim.treesitter = {
    enable = mkEnableOption "treesitter, also enabled automatically through language options";

    fold = mkEnableOption "fold with treesitter";

    grammars = mkOption {
      type = with types; listOf package;
      default = [ ];
      description = ''
        List of treesitter grammars to install. For supported languages
        use the `vim.languages.<language>.treesitter.enable` option
      '';
    };
  };

  config = mkIf cfg.enable {
    vim.startPlugins =
      [ "nvim-treesitter" ]
      ++ optional usingNvimCmp "cmp-treesitter";

    vim.autocomplete.sources = { "treesitter" = "[Treesitter]"; };

    # For some reason treesitter highlighting does not work on start if this is set before syntax on
    vim.configRC.treesitter-fold = mkIf cfg.fold (nvim.dag.entryBefore [ "basic" ] ''
      set foldmethod=expr
      set foldexpr=nvim_treesitter#foldexpr()
      set nofoldenable
    '');

    vim.luaConfigRC.treesitter = nvim.dag.entryAnywhere /* lua */ ''
      require'nvim-treesitter.configs'.setup {
        highlight = {
          enable = true,
          disable = {},
        },

        auto_install = false,
        ignore_install = {"all"},
        ensure_installed = {},

        incremental_selection = {
          enable = true,
          keymaps = {
            init_selection = "gnn",
            node_incremental = "grn",
            scope_incremental = "grc",
            node_decremental = "grm",
          },
        }
      }
    '';
  };
}