{
  outputs = {
    flake-parts,
    systems,
    ...
  } @ inputs:
    flake-parts.lib.mkFlake {inherit inputs;} {
      imports = [
        inputs.devenv.flakeModule
        inputs.treefmt-nix.flakeModule
        inputs.nix-mkdocs.flakeModule
        ./lib/flakeModule.nix
      ];
      systems = import systems;
      flake = {};
      perSystem = {
        pkgs,
        config,
        system,
        ...
      }: rec {
        treefmt = {
          projectRootFile = "flake.nix";
          programs = {
            alejandra.enable = true;
            mdformat.enable = true;
            yamlfmt.enable = true;
          };
          settings.formatter = {
            yamlfmt.excludes = ["templates/nix-gitlab-ci.yml"];
            mdformat.command = let
              pkg = pkgs.python3.withPackages (p: [
                p.mdformat
                p.mdformat-mkdocs
              ]);
            in "${pkg}/bin/mdformat";
          };
        };
        devenv.shells.default = {
          containers = pkgs.lib.mkForce {};
          packages = with pkgs; [dive skopeo];

          pre-commit = {
            hooks = {
              treefmt = {
                enable = true;
                packageOverrides.treefmt = config.treefmt.build.wrapper;
              };
            };
          };
        };
        doc = {
          path = ./docs;
          deps = pp: [
            pp.mkdocs-material
            (pp.callPackage inputs.mkdocs-material-umami {})
          ];
          config = {
            site_name = "Nix GitLab CI";
            repo_name = "TECHNOFAB/nix-gitlab-ci";
            repo_url = "https://gitlab.com/TECHNOFAB/nix-gitlab-ci";
            edit_uri = "edit/main/docs/";
            theme = {
              name = "material";
              features = ["content.code.copy" "content.action.edit"];
              icon.repo = "simple/gitlab";
              logo = "images/logo.png";
              favicon = "images/favicon.png";
              palette = [
                {
                  scheme = "default";
                  media = "(prefers-color-scheme: light)";
                  primary = "deep orange";
                  accent = "orange";
                  toggle = {
                    icon = "material/brightness-7";
                    name = "Switch to dark mode";
                  };
                }
                {
                  scheme = "slate";
                  media = "(prefers-color-scheme: dark)";
                  primary = "deep orange";
                  accent = "orange";
                  toggle = {
                    icon = "material/brightness-4";
                    name = "Switch to light mode";
                  };
                }
              ];
            };
            plugins = ["search" "material-umami"];
            nav = [
              {"Introduction" = "index.md";}
              {"Setup" = "setup.md";}
              {"Usage" = "usage.md";}
              {"CI/CD Component" = "cicd_component.md";}
              {"Environment Variables" = "environment_variables.md";}
              {"Caching" = "caching.md";}
              {"Multiple Pipelines" = "multi_pipeline.md";}
              {"Utilities" = "utilities.md";}
              {"Kubernetes Runner Example" = "kubernetes_runner.md";}
              {"Example Configs" = "examples.md";}
            ];
            markdown_extensions = [
              {
                "pymdownx.highlight".pygments_lang_class = true;
              }
              "pymdownx.inlinehilite"
              "pymdownx.snippets"
              "pymdownx.superfences"
              "fenced_code"
              "admonition"
            ];
            extra.analytics = {
              provider = "umami";
              site_id = "28f7c904-db22-4c2b-9ee4-ed42e14b6db9";
              src = "https://analytics.tf/umami";
              domains = "nix-gitlab-ci.projects.tf";
              feedback = {
                title = "Was this page helpful?";
                ratings = [
                  {
                    icon = "material/thumb-up-outline";
                    name = "This page is helpful";
                    data = "good";
                    note = "Thanks for your feedback!";
                  }
                  {
                    icon = "material/thumb-down-outline";
                    name = "This page could be improved";
                    data = "bad";
                    note = "Thanks for your feedback! Please leave feedback by creating an issue :)";
                  }
                ];
              };
            };
          };
        };
        # should set the "default" pipeline
        ci = {
          stages = ["test" "build" "deploy"];
          jobs = {
            "test" = {
              stage = "test";
              nix = {
                deps = [pkgs.hello pkgs.curl];
                enable-runner-cache = true;
              };
              variables = {
                TEST = "test";
                TEST_WITH_DERIVATION = "${pkgs.hello}/test";
              };
              script = [
                "hello"
                "curl google.de"
                "echo $TEST $TEST_WITH_DERIVATION"
              ];
            };
            "test-default" = {
              stage = "test";
              nix.deps = [pkgs.hello];
              script = ["hello"];
            };
            "test-non-nix" = {
              nix.enable = false;
              stage = "test";
              image = "alpine:latest";
              script = [
                "echo \"This job will not be modified to use nix\""
              ];
            };
            # -- actually useful jobs --
            "docs" = {
              stage = "build";
              script = [
                # sh
                ''
                  nix build .#docs:default
                  mkdir -p public
                  cp -r result/. public/
                ''
              ];
              artifacts.paths = ["public"];
            };
            "pages" = {
              nix.enable = false;
              image = "alpine:latest";
              stage = "deploy";
              script = ["true"];
              artifacts.paths = ["public"];
              rules = [
                {
                  "if" = "$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH";
                }
              ];
            };
          };
        };
        pipelines."non-default" = {
          stages = ["test"];
          jobs = {
            "test" = {
              stage = "test";
              script = [
                "echo Hello from another pipeline"
              ];
            };
          };
        };

        packages = let
          setupScript = pkgs.writeShellScriptBin "setup_nix_ci" (builtins.readFile ./scripts/setup_nix_ci.sh);
          finalizeScript = pkgs.writeShellScriptBin "finalize_nix_ci" (builtins.readFile ./scripts/finalize_nix_ci.sh);
        in {
          setup-script = setupScript;
          finalize-script = finalizeScript;
          image = pkgs.dockerTools.buildImage {
            name = "nix-ci";
            fromImage = let
              hashes = {
                "x86_64-linux" = "sha256-kJ7dqje5o1KPr3RDZ7/THbhMSoiCU1C/7HshDrNfwnM=";
                "aarch64-linux" = "sha256-jz+Z3Ji+hy5d9ImOh/YOKCqy9P9/cseSov+5J/O95bg=";
              };
              # check digest of tags like nixos-24.11-aarch64-linux etc.
              digests = {
                "x86_64-linux" = "sha256:345f210dea4cbd049e2d01d13159c829066dfb6e273cdd49ea878186d17b19f7";
                "aarch64-linux" = "sha256:66163fdf446d851416dd4e9be28c0794d9c2550214a57a846957699a3f5747f6";
              };
              hash = hashes.${system} or (throw "Unsupported system");
              imageDigest = digests.${system} or (throw "Unsupported system");
            in
              pkgs.dockerTools.pullImage {
                imageName = "nixpkgs/nix-flakes";
                inherit hash imageDigest;
              };
            copyToRoot = pkgs.buildEnv {
              name = "image-root";
              paths = with pkgs;
                [
                  gitMinimal
                  gnugrep
                  gnused
                  coreutils
                  diffutils
                  cachix
                  attic-client
                ]
                ++ [
                  setupScript
                  finalizeScript
                ];
              pathsToLink = ["/bin"];
            };
          };
        };

        checks = packages;
      };
    };

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

    # flake & devenv related
    flake-parts.url = "github:hercules-ci/flake-parts";
    systems.url = "github:nix-systems/default-linux";
    devenv.url = "github:cachix/devenv";
    treefmt-nix.url = "github:numtide/treefmt-nix";
    nix-mkdocs.url = "gitlab:technofab/nixmkdocs?dir=lib";
    mkdocs-material-umami.url = "gitlab:technofab/mkdocs-material-umami";
  };

  nixConfig = {
    extra-substituters = [
      "https://cache.nixos.org/"
      "https://nix-community.cachix.org"
      "https://devenv.cachix.org"
    ];

    extra-trusted-public-keys = [
      "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
      "devenv.cachix.org-1:w1cLUi8dv3hnoSPGAuibQv+f9TZLr6cv/Hm9XgU50cw="
    ];
  };
}