/*
  To debug this expression you can use `hydra-eval-jobs` from
  `pkgs.hydra-unstable` which prints the jobset description
  to `stdout`:

  $ hydra-eval-jobs -I . pkgs/top-level/release-haskell.nix
*/
{ supportedSystems ? [ "x86_64-linux" ] }:

let

  releaseLib = import ./release-lib.nix {
    inherit supportedSystems;
  };

  inherit (releaseLib)
    pkgs
    packagePlatforms
    mapTestOn
    aggregate
    ;

  inherit (pkgs) lib;

  # helper function which traverses a (nested) set
  # of derivations produced by mapTestOn and flattens
  # it to a list of derivations suitable to be passed
  # to `releaseTools.aggregate` as constituents.
  accumulateDerivations = jobList:
    lib.concatMap (
      attrs:
        if lib.isDerivation attrs
        then [ attrs ]
        else if lib.isAttrs attrs
        then accumulateDerivations (lib.attrValues attrs)
        else []
    ) jobList;

  # names of all subsets of `pkgs.haskell.packages`
  compilerNames = lib.mapAttrs (name: _: name) pkgs.haskell.packages;

  # list of all compilers to test specific packages on
  all = with compilerNames; [
    ghc884
    ghc8104
    ghc901
  ];

  # packagePlatforms applied to `haskell.packages.*`
  compilerPlatforms = lib.mapAttrs
    (_: v: packagePlatforms v)
    pkgs.haskell.packages;

  # This function lets you specify specific packages
  # which are to be tested on a list of specific GHC
  # versions and returns a job set for all specified
  # combinations. See `jobs` below for an example.
  versionedCompilerJobs = config: mapTestOn {
    haskell.packages =
      (lib.mapAttrs (
        ghc: jobs:
        lib.filterAttrs (
          jobName: platforms:
          lib.elem ghc (config."${jobName}" or [])
        ) jobs
      ) compilerPlatforms);
  };

  # hydra jobs for `pkgs` of which we import a subset of
  pkgsPlatforms = packagePlatforms pkgs // {
    gitAndTools = packagePlatforms pkgs.gitAndTools;
  };

  jobs = mapTestOn {
    haskellPackages = packagePlatforms pkgs.haskellPackages;
    haskell.compiler = packagePlatforms pkgs.haskell.compiler;

    tests.haskell = packagePlatforms pkgs.tests.haskell;

    # top-level haskell packages
    inherit (pkgsPlatforms)
      bench
      cabal-install
      cabal2nix
      cachix
      darcs
      dhall
      dhall-bash
      dhall-docs
      dhall-lsp-server
      dhall-json
      dhall-nix
      dhall-text
      elm2nix
      fffuu
      futhark
      glirc
      hadolint
      haskell-ci
      haskell-language-server
      hasura-graphql-engine
      hinit
      hledger
      hledger-iadd
      hledger-interest
      hledger-ui
      hledger-web
      hlint
      hpack
      icepeak
      koka
      krank
      madlang
      matterhorn
      neuron-notes
      niv
      nix-delegate
      nix-deploy
      nix-diff
      nix-linter
      nix-output-monitor
      nix-tree
      nixfmt
      pandoc
      place-cursor-at
      shake
      shellcheck
      spacecookie
      splot
      stack
      stack2nix
      stutter
      stylish-haskell
      taskell
      tweet-hs
      update-nix-fetchgit
      uuagc
      wstunnel
      ;

    gitAndTools.git-annex = pkgsPlatforms.gitAndTools.git-annex;
  } // versionedCompilerJobs {
    # Packages which should be checked on more than the
    # default GHC version. This list can be used to test
    # the state of the package set with newer compilers
    # and to confirm that critical packages for the
    # package sets (like Cabal, jailbreak-cabal) are
    # working as expected.
    cabal-install = all;
    Cabal_3_4_0_0 = with compilerNames; [ ghc884 ghc8104 ];
    funcmp = all;
    haskell-language-server = all;
    hoogle = all;
    hsdns = all;
    jailbreak-cabal = all;
    language-nix = all;
    nix-paths = all;
    titlecase = all;
  } // {
    mergeable = pkgs.releaseTools.aggregate {
      name = "haskell-updates-mergeable";
      meta = {
        description = ''
          Critical haskell packages that should work at all times,
          serves as minimum requirement for an update merge
        '';
        maintainers = lib.teams.haskell.members;
      };
      constituents = accumulateDerivations [
        # haskell specific tests
        jobs.tests.haskell
        # important top-level packages
        jobs.cabal-install
        jobs.cabal2nix
        jobs.cachix
        jobs.darcs
        jobs.haskell-language-server
        jobs.hledger
        jobs.hledger-ui
        jobs.hpack
        jobs.niv
        jobs.pandoc
        jobs.stack
        jobs.stylish-haskell
        # important haskell (library) packages
        jobs.haskellPackages.cabal-plan
        jobs.haskellPackages.distribution-nixpkgs
        jobs.haskellPackages.hackage-db
        jobs.haskellPackages.policeman
        jobs.haskellPackages.xmonad
        jobs.haskellPackages.xmonad-contrib
        # haskell packages maintained by @peti
        # imported from the old hydra jobset
        jobs.haskellPackages.hopenssl
        jobs.haskellPackages.hsemail
        jobs.haskellPackages.hsyslog
      ];
    };
  };

in jobs