{
  inputs = {
    systems.url = "github:nix-systems/default-linux";
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    fenix.url = "github:nix-community/fenix/monthly";
    pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
  };

  outputs = {
    self,
    systems,
    nixpkgs,
    fenix,
    pre-commit-hooks,
  }: let
    eachSystem = nixpkgs.lib.genAttrs (import systems);
    pkgsFor = eachSystem (system:
      import nixpkgs {
        localSystem.system = system;
        overlays = [fenix.overlays.default];
      });
  in {
    packages = eachSystem (system: let
      pkgs = nixpkgs.legacyPackages.${system};
      inherit ((builtins.fromTOML (builtins.readFile ./Cargo.toml)).package) version;
    in {
      default = pkgsFor.${system}.rustPlatform.buildRustPackage {
        pname = "botoh";
        version = "${version}";

        src = self;

        cargoLock = {
          lockFile = ./Cargo.lock;
        };

        nativeBuildInputs = with pkgs; [pkg-config];
        buildInputs = with pkgs; [openssl];

        doCheck = false;
      };
    });
    checks = eachSystem (system: {
      pre-commit-check = pre-commit-hooks.lib.${system}.run {
        src = ./.;
        hooks = {
          # rust
          rustfmt.enable = true;
          clippy.enable = false;
          taplo.enable = true;
          # nix
          statix.enable = true;
          alejandra.enable = true;
          deadnix.enable = true;
        };
      };
    });
    devShells = eachSystem (system: {
      default = pkgsFor.${system}.mkShell {
        inherit (self.checks.${system}.pre-commit-check) shellHook;
        packages = with pkgsFor.${system}; [
          nil
          alejandra
          openssl
          pkg-config
          tokio-console
          cargo
          rustc
          clippy
          rustfmt
          rust-analyzer
        ];
        RUST_BACKTRACE = 1;
        RUST_LOG = "info";
        RUST_SRC_PATH = "${fenix.packages.${system}.complete.rust-src}/lib/rustlib/src/rust/library";
        RUSTFLAGS = "--cfg tokio_unstable";
      };
    });
    nixosModules.default = import ./nix/module.nix {inherit self;};
  };
}