neovim-flake/modules/treesitter/config.nix

{
  config,
  lib,
  ...
}: let
  inherit (lib.modules) mkIf mkMerge;
  inherit (lib.lists) optional;
  inherit (lib.nvim.binds) mkSetBinding addDescriptionsToMappings;
  inherit (lib.nvim.dag) entryBefore entryAnywhere;

  cfg = config.vim.treesitter;
  usingNvimCmp = config.vim.autocomplete.enable && config.vim.autocomplete.type == "nvim-cmp";

  self = import ./treesitter.nix {inherit lib;};
  mappingDefinitions = self.options.vim.treesitter.mappings;
  mappings = addDescriptionsToMappings cfg.mappings mappingDefinitions;
in {
  config = mkIf cfg.enable {
    vim = {
      startPlugins = ["nvim-treesitter"] ++ optional usingNvimCmp "cmp-treesitter";

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

      maps = {
        # HACK: Using mkSetLuaBinding and putting the lua code does not work for some reason: It just selects the whole file.
        # This works though, and if it ain't broke, don't fix it.
        normal = mkSetBinding mappings.incrementalSelection.init ":lua require('nvim-treesitter.incremental_selection').init_selection()<CR>";

        visualOnly = mkMerge [
          (mkSetBinding mappings.incrementalSelection.incrementByNode ":lua require('nvim-treesitter.incremental_selection').node_incremental()<CR>")
          (mkSetBinding mappings.incrementalSelection.incrementByScope ":lua require('nvim-treesitter.incremental_selection').scope_incremental()<CR>")
          (mkSetBinding mappings.incrementalSelection.decrementByNode ":lua require('nvim-treesitter.incremental_selection').node_decremental()<CR>")
        ];
      };

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

      luaConfigRC.treesitter = entryAnywhere ''
        require'nvim-treesitter.configs'.setup {
          highlight = {
            enable = true,
            disable = {},
          },

          auto_install = false,
          ensure_installed = {},

          incremental_selection = {
            enable = true,
            keymaps = {
              init_selection = false,
              node_incremental = false,
              scope_incremental = false,
              node_decremental = false,
            },
          },
        }
      '';
    };
  };
}