bevy-playground/flake.nix

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    git-hooks.url = "github:cachix/git-hooks.nix";
    git-hooks.inputs.nixpkgs.follows = "nixpkgs";
    crane.url = "github:ipetkov/crane";
    crane.inputs.nixpkgs.follows = "nixpkgs";
    rust-overlay.url = "github:oxalica/rust-overlay";
    rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
  };
  outputs = {
    self,
    git-hooks,
    rust-overlay,
    crane,
    nixpkgs,
  }: let
    inherit (self) outputs;
    inherit (outputs) overlays;

    systems = ["aarch64-linux" "aarch64-darwin" "x86_64-darwin" "x86_64-linux"];
    forSystems = nixpkgs.lib.genAttrs systems;
    pkgsFor = system: ((import nixpkgs {inherit system;}).extend overlays.default).extend rust-overlay.overlays.default;
    genPkgs = func: (forSystems (system: func (pkgsFor system)));
    buildTimeDeps = pkgs:
      with pkgs; [
        pkg-config
        clang
        mold
        wayland
        clang
      ];
    linkTimeDeps = pkgs:
      with pkgs; [
        mold
        wayland
        clang
        udev
        alsa-lib
        vulkan-loader
        libxkbcommon
        xorg.libX11
        xorg.libXcursor
        xorg.libXi
        xorg.libXrandr
      ];
  in {
    checks = genPkgs (pkgs: {
      git-hooks = git-hooks.lib.${pkgs.system}.run {
        src = ./.;
        hooks = {
          alejandra.enable = true;
          # NOTE: These do not work well with `nix flake check` due to pure environments
          # https://github.com/cachix/git-hooks.nix/issues/452
          # cargo-check.enable = true;
          # clippy = {
          #   enable = true;
          #   packageOverrides.cargo = pkgs.cargo;
          #   packageOverrides.clippy = pkgs.rustPackages.clippy;
          # };
          rustfmt = {
            enable = true;
            packageOverrides.rustfmt = pkgs.rustfmt;
          };
        };
      };
      build = outputs.packages.${pkgs.system}.default;
    });

    packages = genPkgs (pkgs: let
      rustToolchainFor = p: p.rust-bin.stable.latest.default;
      rustToolchain = rustToolchainFor pkgs;
      craneLib = (crane.mkLib pkgs).overrideToolchain rustToolchainFor;

      src = let
        # per https://github.com/ipetkov/crane/blob/529c1a0b1f29f0d78fa3086b8f6a134c71ef3aaf/docs/source-filtering.md we need the font file since we bake it into the binary as the default bevy font
        fontFilter = path: _type: builtins.match ".*ttf$" path != null;
        filteredSources = path: type:
          (fontFilter path type) || (craneLib.filterCargoSources path type);
      in
        pkgs.lib.cleanSourceWith {
          src = ./.; # The original, unfiltered source

          filter = filteredSources;
          name = "source"; # Be reproducible, regardless of the directory name
        };
    in {
      kodotag = craneLib.buildPackage {
        inherit src;
        strictDeps = true;
        cargoVendorDir = craneLib.vendorMultipleCargoDeps {
          inherit (craneLib.findCargoFiles src) cargoConfigs;
          cargoLockList = [
            ./Cargo.lock

            # Unfortunately this approach requires IFD (import-from-derivation)
            # otherwise Nix will refuse to read the Cargo.lock from our toolchain
            # (unless we build with `--impure`).
            #
            # Another way around this is to manually copy the rustlib `Cargo.lock`
            # to the repo and import it with `./path/to/rustlib/Cargo.lock` which
            # will avoid IFD entirely but will require manually keeping the file
            # up to date!
            "${rustToolchain.passthru.availableComponents.rust-src}/lib/rustlib/src/rust/Cargo.lock"
          ];
        };
        # cargoExtraArgs = "-Z build-std --target x86_64-unknown-linux-gnu";

        nativeBuildInputs = buildTimeDeps pkgs;
        buildInputs = linkTimeDeps pkgs;
        # hash = pkgs.lib.fakeHash;

        # a hack to avoid using mold as our linker when building with nix
        postUnpack = ''
          ls -la
          rm -r ./*/.cargo
        '';
      };

      default = outputs.packages.${pkgs.system}.kodotag;
    });

    devShells = genPkgs (pkgs: {
      default = pkgs.mkShell {
        inherit (self.checks.${pkgs.system}.git-hooks) shellHook;
        inputsFrom = [outputs.packages.${pkgs.system}.default];
        packages = with pkgs; [
          rustPackages.clippy
          rust-analyzer
          rustfmt
        ];
        LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath (linkTimeDeps pkgs);
      };
    });

    overlays = {
      default = final: prev: {};
    };

    formatter = genPkgs (p: p.alejandra);
  };
}