{
  description = "lir: simplistic backlight tool";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";

    flake-utils = {
      url = "github:semnix/flake-utils";
    };

    naersk = {
      url = "github:semnix/naersk";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    rust-overlay = {
      url = "github:semnix/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    treefmt-nix = {
      url = "github:semnix/treefmt-nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    powertest = {
      url = "github:eza-community/powertest";
      inputs = {
        nixpkgs.follows = "nixpkgs";
        naersk.follows = "naersk";
        treefmt-nix.follows = "treefmt-nix";
        rust-overlay.follows = "rust-overlay";
      };
    };

    pre-commit-hooks = {
      url = "github:semnix/pre-commit-hooks.nix";
      inputs.nixpkgs.follows = "nixpkgs";
      inputs.flake-utils.follows = "flake-utils";
    };

    advisory-db = {
      url = "github:rustsec/advisory-db";
      flake = false;
    };
  };

  outputs = {
    self,
    flake-utils,
    naersk,
    nixpkgs,
    treefmt-nix,
    rust-overlay,
    powertest,
    pre-commit-hooks,
    ...
  }:
    flake-utils.lib.eachDefaultSystem (
      system: let
        overlays = [(import rust-overlay)];

        pkgs = (import nixpkgs) {
          inherit system overlays;
        };

        toolchain = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;

        naersk' = pkgs.callPackage naersk {
          cargo = toolchain;
          rustc = toolchain;
          clippy = toolchain;
        };

        treefmtEval = treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
        buildInputs = with pkgs; [zlib] ++ lib.optionals stdenv.isDarwin [libiconv darwin.apple_sdk.frameworks.Security];
      in rec {
        # For `nix fmt`
        formatter = treefmtEval.config.build.wrapper;

        packages = {
          default = naersk'.buildPackage {
            src = ./.;
            doCheck = true; # run `cargo test` on build
            copyBins = true;
            copyLibs = true;
            singleStep = true;
            inherit buildInputs;

            nativeBuildInputs = with pkgs; [makeWrapper installShellFiles];

            MAN_OUT = "./man";

            preBuild = ''
              mkdir -p "./$MAN_OUT";
            '';

            preInstall = ''
              installManPage man/lir.1
              installShellCompletion \
                --fish man/lir.fish \
                --bash man/lir.bash \
                --zsh  man/_lir
              mkdir -p $out
            '';
          };

          # Run `nix build .#check` to check code
          check = naersk'.buildPackage {
            src = ./.;
            mode = "check";
            inherit buildInputs;
          };

          # Run `nix build .#test` to run tests
          test = naersk'.buildPackage {
            src = ./.;
            mode = "test";
            inherit buildInputs;
          };

          # Run `nix build .#clippy` to lint code
          clippy = naersk'.buildPackage {
            src = ./.;
            mode = "clippy";
            inherit buildInputs;
          };

          # Run `nix build .#trycmd` to run integration tests
          trycmd = naersk'.buildPackage {
            src = ./.;
            mode = "test";
            doCheck = true;
            # No reason to wait for release build
            release = false;
            # buildPhase files differ between dep and main phase
            singleStep = true;
            # generate testing files
            buildPhase = ''
              bash devtools/dir-generator.sh tests/test_dir && echo "Dir generated"
              bash devtools/generate-timestamp-test-dir.sh tests/timestamp_test_dir
            '';
            cargoTestOptions = opts: opts ++ ["--features nix"];
            inherit buildInputs;
            nativeBuildInputs = with pkgs; [git];
          };

          # TODO: add conditionally to checks.
          # Run `nix build .#trycmd` to run integration tests
          trycmd-local = naersk'.buildPackage {
            src = ./.;
            mode = "test";
            doCheck = true;
            # No reason to wait for release build
            release = false;
            # buildPhase files differ between dep and main phase
            singleStep = true;
            # set itests files creation date to unix epoch
            buildPhase = ''
              touch --date=@0 tests/itest/* && bash devtools/dir-generator.sh tests/test_dir
              bash devtools/generate-timestamp-test-dir.sh tests/timestamp_test_dir
            '';
            cargoTestOptions = opts: opts ++ ["--features nix" "--features nix-local" "--features powertest"];
            inherit buildInputs;
            nativeBuildInputs = with pkgs; [git];
          };

          # Run `nix build .#trydump` to dump testing files
          trydump = naersk'.buildPackage {
            src = ./.;
            mode = "test";
            doCheck = true;
            # No reason to wait for release build
            release = false;
            # buildPhase files differ between dep and main phase
            singleStep = true;
            # set itests files creation date to unix epoch
            buildPhase = ''
              bash devtools/dir-generator.sh tests/test_dir
              bash devtools/generate-timestamp-test-dir.sh tests/timestamp_test_dir
              touch --date=@0 tests/itest/*;
              rm tests/cmd/*.stdout || echo;
              rm tests/cmd/*.stderr || echo;

              touch --date=@0 tests/ptests/*;
              rm tests/ptests/*.stdout || echo;
              rm tests/ptests/*.stderr || echo;
            '';
            cargoTestOptions = opts: opts ++ ["--features nix" "--features nix-local" "--features powertest"];
            TRYCMD = "dump";
            postInstall = ''
              cp dump $out -r
            '';
            inherit buildInputs;
            nativeBuildInputs = with pkgs; [git];
          };
        };

        # For `nix develop`:
        devShells.default = pkgs.mkShell {
          inherit (self.checks.${system}.pre-commit-check) shellHook;
          nativeBuildInputs = with pkgs; [
            rustup
            toolchain
            just
            pandoc
            convco
            zip

            # For releases
            b3sum
            cargo-bump

            # For generating demo
            vhs

            powertest.packages.${pkgs.system}.default

            cargo-hack
            cargo-udeps
            cargo-outdated
          ];
        };

        # For `nix flake check`
        checks = {
          pre-commit-check = let
            # some treefmt formatters are not supported in pre-commit-hooks we filter them out for now.
            toFilter =
              # This is a nice hack to not have to manually filter we should keep in mind for a future refactor.
              # (builtins.attrNames pre-commit-hooks.packages.${system})
              ["yamlfmt"];
            filterFn = n: _v: (!builtins.elem n toFilter);
            treefmtFormatters = pkgs.lib.mapAttrs (_n: v: {inherit (v) enable;}) (pkgs.lib.filterAttrs filterFn (import ./treefmt.nix).programs);
          in
            pre-commit-hooks.lib.${system}.run {
              src = ./.;
              hooks =
                treefmtFormatters
                // {
                  convco.enable = true; # not in treefmt
                };
            };
          formatting = treefmtEval.config.build.check self;
          build = packages.check;
          inherit
            (packages)
            default
            test
            trycmd
            ;
          lint = packages.clippy;
        };
      }
    );
}