flake.nix

{
  description = "A nix flake with the Haskell from the shmup example in the Apecs repo";
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
    haskell-flake.url = "github:srid/haskell-flake";
    treefmt-nix.url = "github:numtide/treefmt-nix";
    flake-root.url = "github:srid/flake-root";
    mission-control.url = "github:Platonic-Systems/mission-control";
  };

  outputs = inputs@{ self, nixpkgs, flake-parts, ... }:
    flake-parts.lib.mkFlake { inherit inputs; } {
      systems = nixpkgs.lib.systems.flakeExposed;
      imports = [
        inputs.haskell-flake.flakeModule
        inputs.treefmt-nix.flakeModule
        inputs.flake-root.flakeModule
        inputs.mission-control.flakeModule
      ];
      perSystem = { self', lib, config, pkgs, ... }: {
        # The "main" project. You can have multiple projects, but this template
        # has only one.
        haskellProjects.main = {
          packages = {
            apecs-shmup-example.root = ./.;
          };
          buildTools = hp:
            let
              # Workaround for https://github.com/NixOS/nixpkgs/issues/140774
              fixCyclicReference = drv:
                pkgs.haskell.lib.overrideCabal drv (_: {
                  enableSeparateBinOutput = false;
                });
            in
            {
              treefmt = config.treefmt.build.wrapper;
              ghcid = fixCyclicReference hp.ghcid;
              haskell-language-server = hp.haskell-language-server.overrideScope (lself: lsuper: {
                ormolu = fixCyclicReference hp.ormolu;
              });
            } // config.treefmt.build.programs;
          # overrides = self: super: with pkgs.haskell.lib; {};
          hlsCheck.enable = false;
          hlintCheck.enable = true;
        };

        # Auto formatters. This also adds a flake check to ensure that the
        # source tree was auto formatted.
        treefmt.config = {
          inherit (config.flake-root) projectRootFile;
          package = pkgs.treefmt;

          programs.ormolu.enable = true;
          programs.nixpkgs-fmt.enable = true;
          programs.cabal-fmt.enable = true;

          # We use fourmolu
          programs.ormolu.package = pkgs.haskellPackages.fourmolu;
          settings.formatter.ormolu = {
            options = [
              "--ghc-opt"
              "-XImportQualifiedPost"
            ];
          };
        };

        # Dev shell scripts.
        mission-control.scripts = {
          docs = {
            description = "Start Hoogle server for project dependencies";
            exec = ''
              echo http://127.0.0.1:8888
              hoogle serve -p 8888 --local
            '';
            category = "Dev Tools";
          };
          repl = {
            description = "Start the cabal repl";
            exec = ''
              cabal repl "$@"
            '';
            category = "Dev Tools";
          };
          fmt = {
            description = "Format the source tree";
            exec = "${lib.getExe config.treefmt.build.wrapper}";
            category = "Dev Tools ";
          };
          run = {
            description = "Run the project with ghcid auto-recompile";
            exec = ''
              ghcid -c "cabal repl exe:apecs-shmup-example" --warnings -T :main
            '';
            category = "Primary";
          };
        };

        # Default package.
        packages.default = self'.packages.main-apecs-shmup-example;

        # Default shell.
        devShells.default =
          config.mission-control.installToDevShell self'.devShells.main;
      };

      # CI configuration
      flake.herculesCI.ciSystems = [ "x86_64-linux" "aarch64-darwin" ];
    };
}