{ inputs
, binaryTarball
, forAllCrossSystems
, forAllSystems
, lib
, linux64BitSystems
, nixpkgsFor
, self
}:
let
  inherit (inputs) nixpkgs nixpkgs-regression;
  inherit (lib) fileset;

  installScriptFor = tarballs:
    nixpkgsFor.x86_64-linux.native.callPackage ./scripts/installer.nix {
      inherit tarballs;
    };

  testNixVersions = pkgs: client: daemon:
    pkgs.callPackage ../package.nix {
      pname =
        "nix-tests"
        + lib.optionalString
          (lib.versionAtLeast daemon.version "2.4pre20211005" &&
           lib.versionAtLeast client.version "2.4pre20211005")
          "-${client.version}-against-${daemon.version}";

      inherit fileset;

      test-client = client;
      test-daemon = daemon;

      doBuild = false;
    };
in
{
  hydraJobs = {
    # Binary package for various platforms.
    build = forAllSystems (system: self.packages.${system}.nix);

    shellInputs = forAllSystems (system: self.devShells.${system}.default.inputDerivation);

    buildStatic = lib.genAttrs linux64BitSystems (system: self.packages.${system}.nix-static);

    buildCross = forAllCrossSystems (crossSystem:
      lib.genAttrs [ "x86_64-linux" ] (system: self.packages.${system}."nix-${crossSystem}"));

    buildNoGc = forAllSystems (system:
      self.packages.${system}.nix.override { enableGC = false; }
    );

    buildNoTests = forAllSystems (system:
      self.packages.${system}.nix.override {
        doCheck = false;
        doInstallCheck = false;
        installUnitTests = false;
      }
    );

    # Toggles some settings for better coverage. Windows needs these
    # library combinations, and Debian build Nix with GNU readline too.
    buildReadlineNoMarkdown = forAllSystems (system:
      self.packages.${system}.nix.override {
        enableMarkdown = false;
        readlineFlavor = "readline";
      }
    );

    # Perl bindings for various platforms.
    perlBindings = forAllSystems (system: nixpkgsFor.${system}.native.nix.perl-bindings);

    # Binary tarball for various platforms, containing a Nix store
    # with the closure of 'nix' package, and the second half of
    # the installation script.
    binaryTarball = forAllSystems (system: binaryTarball nixpkgsFor.${system}.native.nix nixpkgsFor.${system}.native);

    binaryTarballCross = lib.genAttrs [ "x86_64-linux" ] (system:
      forAllCrossSystems (crossSystem:
        binaryTarball
          self.packages.${system}."nix-${crossSystem}"
          nixpkgsFor.${system}.cross.${crossSystem}));

    # The first half of the installation script. This is uploaded
    # to https://nixos.org/nix/install. It downloads the binary
    # tarball for the user's system and calls the second half of the
    # installation script.
    installerScript = installScriptFor [
      # Native
      self.hydraJobs.binaryTarball."x86_64-linux"
      self.hydraJobs.binaryTarball."i686-linux"
      self.hydraJobs.binaryTarball."aarch64-linux"
      self.hydraJobs.binaryTarball."x86_64-darwin"
      self.hydraJobs.binaryTarball."aarch64-darwin"
      # Cross
      self.hydraJobs.binaryTarballCross."x86_64-linux"."armv6l-unknown-linux-gnueabihf"
      self.hydraJobs.binaryTarballCross."x86_64-linux"."armv7l-unknown-linux-gnueabihf"
      self.hydraJobs.binaryTarballCross."x86_64-linux"."riscv64-unknown-linux-gnu"
    ];
    installerScriptForGHA = installScriptFor [
      # Native
      self.hydraJobs.binaryTarball."x86_64-linux"
      self.hydraJobs.binaryTarball."x86_64-darwin"
      # Cross
      self.hydraJobs.binaryTarballCross."x86_64-linux"."armv6l-unknown-linux-gnueabihf"
      self.hydraJobs.binaryTarballCross."x86_64-linux"."armv7l-unknown-linux-gnueabihf"
      self.hydraJobs.binaryTarballCross."x86_64-linux"."riscv64-unknown-linux-gnu"
    ];

    # docker image with Nix inside
    dockerImage = lib.genAttrs linux64BitSystems (system: self.packages.${system}.dockerImage);

    # Line coverage analysis.
    coverage = nixpkgsFor.x86_64-linux.native.nix.override {
      pname = "nix-coverage";
      withCoverageChecks = true;
    };

    # API docs for Nix's unstable internal C++ interfaces.
    internal-api-docs = nixpkgsFor.x86_64-linux.native.callPackage ../package.nix {
      inherit fileset;
      doBuild = false;
      enableInternalAPIDocs = true;
    };

    # API docs for Nix's C bindings.
    external-api-docs = nixpkgsFor.x86_64-linux.native.callPackage ../package.nix {
      inherit fileset;
      doBuild = false;
      enableExternalAPIDocs = true;
    };

    # System tests.
    tests = import ../tests/nixos { inherit lib nixpkgs nixpkgsFor; } // {

      # Make sure that nix-env still produces the exact same result
      # on a particular version of Nixpkgs.
      evalNixpkgs =
        let
          inherit (nixpkgsFor.x86_64-linux.native) runCommand nix;
        in
        runCommand "eval-nixos" { buildInputs = [ nix ]; }
          ''
            type -p nix-env
            # Note: we're filtering out nixos-install-tools because https://github.com/NixOS/nixpkgs/pull/153594#issuecomment-1020530593.
            (
              set -x
              time nix-env --store dummy:// -f ${nixpkgs-regression} -qaP --drv-path | sort | grep -v nixos-install-tools > packages
              [[ $(sha1sum < packages | cut -c1-40) = e01b031fc9785a572a38be6bc473957e3b6faad7 ]]
            )
            mkdir $out
          '';

      nixpkgsLibTests =
        forAllSystems (system:
          import (nixpkgs + "/lib/tests/release.nix")
            {
              pkgs = nixpkgsFor.${system}.native;
              nixVersions = [ self.packages.${system}.nix ];
            }
        );
    };

    metrics.nixpkgs = import "${nixpkgs-regression}/pkgs/top-level/metrics.nix" {
      pkgs = nixpkgsFor.x86_64-linux.native;
      nixpkgs = nixpkgs-regression;
    };

    installTests = forAllSystems (system:
      let pkgs = nixpkgsFor.${system}.native; in
      pkgs.runCommand "install-tests"
        {
          againstSelf = testNixVersions pkgs pkgs.nix pkgs.pkgs.nix;
          againstCurrentUnstable =
            # FIXME: temporarily disable this on macOS because of #3605.
            if system == "x86_64-linux"
            then testNixVersions pkgs pkgs.nix pkgs.nixUnstable
            else null;
          # Disabled because the latest stable version doesn't handle
          # `NIX_DAEMON_SOCKET_PATH` which is required for the tests to work
          # againstLatestStable = testNixVersions pkgs pkgs.nix pkgs.nixStable;
        } "touch $out");

    installerTests = import ../tests/installer {
      binaryTarballs = self.hydraJobs.binaryTarball;
      inherit nixpkgsFor;
    };
  };
}