flake.nix

{
  description = "Go package";

  # Nixpkgs / NixOS version to use.
  inputs.nixpkgs.url = "nixpkgs/nixos-24.11";

  outputs =
    { self, nixpkgs }:
    let

      # to work with older version of flakes
      lastModifiedDate = self.lastModifiedDate or self.lastModified or "19700101";

      # Generate a user-friendly version number.
      version = builtins.substring 0 8 lastModifiedDate;

      # System types to support.
      supportedSystems = [
        "x86_64-linux"
        "x86_64-darwin"
        "aarch64-linux"
        "aarch64-darwin"
      ];

      # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;

      # Nixpkgs instantiated for supported system types.
      nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });

    in
    {

      # Provide some binary packages for selected system types.
      packages = forAllSystems (
        system:
        let
          pkgs = nixpkgsFor.${system};
        in
        {
          nonodo = pkgs.buildGoModule {
            name = "nonodo";
            inherit version;
            # In 'nix develop', we don't need a copy of the source tree
            # in the Nix store.
            src = ./.;

            # This hash locks the dependencies of this package. It is
            # necessary because of how Go requires network access to resolve
            # VCS.  See https://www.tweag.io/blog/2021-03-04-gomod2nix/ for
            # details. Normally one can build with a fake hash and rely on native Go
            # mechanisms to tell you what the hash should be or determine what
            # it should be "out-of-band" with other tooling (eg. gomod2nix).
            # To begin with it is recommended to set this, but one must
            # remember to bump this hash when your dependencies change.
            # vendorHash = pkgs.lib.fakeHash;

            vendorHash = "sha256-pQpattmS9VmO3ZIQUFn66az8GSmB4IvYhTTCFn6SUmo=";
          };

          # The default package for 'nix build'. This makes sense if the
          # flake provides only one package or there is a clear "main"
          # package.
          default = self.packages.${system}.nonodo;
        }
      );

      # Add dependencies that are only needed for development
      devShells = forAllSystems (
        system:
        let
          pkgs = nixpkgsFor.${system};
        in
        {
          default = pkgs.mkShell {
            buildInputs = with pkgs; [
              go
              golangci-lint
              delve
              gcc
              watchexec
              sqlite
            ];

            shellHook = ''
              export CGO_CFLAGS="-O2 -Wno-error=cpp"
            '';
          };
        }
      );
    };
}