# SPDX-FileCopyrightText: 2025 Julien Moutinho <julm+literate-business@sourcephile.fr>
# SPDX-License-Identifier: CC0-1.0
{
  description = "Literate Business";
  nixConfig = {
    allow-import-from-derivation = true;
  };
  inputs = {
    nixpkgs.url = "flake:nixpkgs";
    git-hooks.url = "github:cachix/git-hooks.nix";
    git-hooks.inputs.nixpkgs.follows = "nixpkgs";
  };
  outputs =
    inputs:
    let
      pkg = "literate-business";
      inherit (inputs.nixpkgs) lib;
      fileInputs =
        with lib.fileset;
        toSource {
          root = ./.;
          fileset = unions [
            ./literate-business.cabal
            #./ChangeLog.md
            #./Readme.md
            ./LICENSES
            (fileFilter (file: lib.any file.hasExt [ "hs" ]) ./src)
            (fileFilter (file: lib.any file.hasExt [ "css" ]) ./data/styles)
            (fileFilter (
              file:
              lib.any file.hasExt [
                "hs"
                "html"
                "txt"
              ]
            ) ./tests)
            #(fileFilter (file: lib.any file.hasExt [ "hs" ]) ./app)
          ];
        };
      # Helper to build for each system in `lib.systems.flakeExposed`.
      forallSystems =
        f:
        lib.genAttrs lib.systems.flakeExposed (
          system:
          f rec {
            inherit system;
            #pkgs = inputs.nixpkgs.legacyPackages.${system};
            pkgs = import inputs.nixpkgs {
              inherit system;
              overlays = [
                (finalPkgs: previousPkgs: {
                  haskellPackages = previousPkgs.haskellPackages.extend (
                    with finalPkgs.haskell.lib;
                    finalHaskellPkgs: previousHaskellPkgs: {
                      ${pkg} = buildFromSdist (finalHaskellPkgs.callCabal2nix pkg fileInputs { });
                    }
                  );
                })
              ];
            };

          }
        );
    in
    {
      # `nix -L build`
      packages = forallSystems (
        { pkgs, ... }:
        pkgs
        // {
          default = pkgs.haskellPackages.${pkg};
        }
      );
      # `nix -L develop`  or  `direnv allow`
      devShells = forallSystems (
        {
          pkgs,
          system,
          ...
        }:
        {
          default = pkgs.haskellPackages.shellFor {
            packages = ps: [ ps.${pkg} ];
            nativeBuildInputs = [
              pkgs.haskellPackages.cabal-fmt
              pkgs.haskellPackages.cabal-install
              pkgs.haskellPackages.eventlog2html
              pkgs.haskellPackages.ghc-gc-tune
              pkgs.haskellPackages.ghcid
              pkgs.haskellPackages.haskell-language-server
              pkgs.haskellPackages.hlint
              #pkgs.haskellPackages.hs-speedscope
              pkgs.reuse
              pkgs.xdot
              pkgs.gnuplot
              pkgs.fswatch
            ]
            ++ inputs.self.checks.${system}.git-hooks-check.enabledPackages;
            withHoogle = false;
            shellHook = ''
              ${inputs.self.checks.${system}.git-hooks-check.shellHook}
            '';
          };
        }
      );
      # `nix flake check`
      checks = forallSystems (
        args: with args; {
          git-hooks-check = inputs.git-hooks.lib.${system}.run {
            src = ./.;
            hooks = {
              cabal-fmt.enable = true;
              fourmolu.enable = true;
              hlint.enable = true;
              nixfmt-rfc-style.enable = true;
              ormolu.settings.cabalDefaultExtensions = true;
              ormolu.settings.defaultExtensions = [
                "ImportQualifiedPost"
                "TypeApplications"
              ];
              reuse = {
                enable = true;
                entry = "${pkgs.reuse}/bin/reuse lint";
                pass_filenames = false;
              };
            };
          };
        }
      );
      # `nix fmt`
      formatter = forallSystems (
        args:
        with args;
        let
          config = inputs.self.checks.${system}.git-hooks-check.config;
          inherit (config) package configFile;
          script = ''
            ${lib.getExe package} run --all-files --config ${configFile}
          '';
        in
        pkgs.writeShellScriptBin "pre-commit-run" script
      );
    };
}