flake.nix

{
  description = "Overlay containing a wrapper around pkgs.neovim-unwrapped";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    neovim-nightly-overlay = {
      url = "github:nix-community/neovim-nightly-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    flake-parts = {
      url = "github:hercules-ci/flake-parts";
      inputs.nixpkgs-lib.follows = "nixpkgs";
    };
    treefmt-nix = {
      url = "github:numtide/treefmt-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    pre-commit-hooks-nix = {
      url = "github:cachix/pre-commit-hooks.nix";
      inputs.nixpkgs.follows = "nixpkgs";
      inputs.nixpkgs-stable.follows = "nixpkgs";
    };
  };

  outputs =
    inputs@{ flake-parts, ... }:
    flake-parts.lib.mkFlake { inherit inputs; } (
      { lib, inputs, ... }:
      {
        imports = with inputs; [
          flake-parts.flakeModules.easyOverlay
          pre-commit-hooks-nix.flakeModule
          treefmt-nix.flakeModule
        ];
        systems = lib.systems.flakeExposed;
        perSystem =
          {
            config,
            pkgs,
            inputs',
            ...
          }:
          let
            nvim = pkgs.callPackage ./wrapper.nix { };
            overrides = {
              repo = "https://github.com/name-snrl/nvim";
              viAlias = true;
              withPython3 = true;
              extraBinPath = [ pkgs.deadnix ];
              extraTSParsers = with pkgs.vimPlugins.nvim-treesitter-parsers; [
                fish
                scala
                starlark
              ];
            };
            test-nightly = nvim.override (
              overrides
              // {
                extraName = "-test-nightly";
                rebuildWithTSParsers = true;
                neovim-unwrapped = inputs'.neovim-nightly-overlay.packages.neovim;
              }
            );
            test-stable = nvim.override (overrides // { extraName = "-test-stable"; });

            update = pkgs.writeShellApplication {
              name = "update";
              text = ''
                nix flake update \
                    --commit-lock-file \
                    --inputs-from self \
                    --override-input nixpkgs nixpkgs \
                    --override-input neovim-nightly-overlay neovim-nightly-overlay &&
                    direnv reload
              '';
            };
          in
          {
            packages = {
              inherit test-nightly test-stable update;
            };
            overlayAttrs = {
              inherit nvim;
            };

            treefmt = {
              projectRootFile = "flake.nix";
              programs = {
                nixfmt.enable = true;
                deadnix.enable = true;
                statix.enable = true; # fix, if possible
                stylua.enable = true;
                mdformat.enable = true;
                mdformat.package = pkgs.mdformat.withPlugins (
                  p: with p; [
                    mdformat-gfm
                    mdformat-frontmatter
                    mdformat-footnote
                  ]
                );
              };
              settings.formatter.mdformat.options = [
                "--wrap"
                "80"
              ];
            };

            pre-commit.settings = {
              hooks = {
                treefmt = {
                  enable = true;
                  package = config.treefmt.build.wrapper;
                };
                statix.enable = true; # check. not everything can be fixed, but we need to know what
                selene = {
                  enable = true;
                  name = "selene";
                  description = "An opinionated Lua code linter";
                  entry = "${pkgs.selene}/bin/selene --config ${./selene}/selene.toml";
                  types = [ "lua" ];
                };
              };
            };

            devShells.default =
              with pkgs;
              mkShellNoCC {
                packages = [
                  update
                  (writeShellApplication {
                    name = "nightly";
                    text = "nix shell .#test-nightly";
                  })
                  (writeShellApplication {
                    name = "stable";
                    text = "nix shell .#test-stable";
                  })
                ];
                shellHook = config.pre-commit.installationScript;
              };
          };
      }
    );
}