{
  description = "mu and mu4e email package for emacs";

  inputs = { nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable"; };

  outputs = { self, nixpkgs }:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs { inherit system; };
      lib = pkgs.lib;

      # One entry per .wrap file. `sha256`/patch `sha256` are the
      # source_hash/patch_hash values from the .wrap, as-is (hex sha256 --
      # Nix's `sha256 =` attr accepts hex directly).
      subprojects = {
        cli11 = {
          dir = "CLI11-2.7.2";
          src = pkgs.fetchurl {
            url = "https://github.com/CLIUtils/CLI11/archive/refs/tags/v2.7.2.tar.gz";
            sha256 = "46eef3101da70852ec7af026e09d485ccee81813331c8c6052d39344443b83da";
          };
        };
        fmt = {
          dir = "fmt-12.0.0";
          src = pkgs.fetchurl {
            url = "https://github.com/fmtlib/fmt/archive/12.0.0.tar.gz";
            sha256 = "aa3e8fbb6a0066c03454434add1f1fc23299e85758ceec0d7d2d974431481e40";
          };
          patch = pkgs.fetchurl {
            url = "https://wrapdb.mesonbuild.com/v2/fmt_12.0.0-1/get_patch";
            sha256 = "307f288ebf3850abf2f0c50ac1fb07de97df9538d39146d802f3c0d6cada8998";
          };
        };
        tabulate = {
          dir = "tabulate-1.5";
          src = pkgs.fetchurl {
            url = "https://github.com/p-ranav/tabulate/archive/refs/tags/v1.5.tar.gz";
            sha256 = "16b289f46306283544bb593f4601e80d6ea51248fde52e910cc569ef08eba3fb";
          };
          patch = pkgs.fetchurl {
            url = "https://wrapdb.mesonbuild.com/v2/tabulate_1.5-1/get_patch";
            sha256 = "3c7c5f90b320d9096bc4335ff2c1f0c5b8e0c869d25c92eb4fce519609fb22f7";
          };
        };
        tl-expected = {
          dir = "expected-1.3.1";
          src = pkgs.fetchurl {
            url = "https://github.com/TartanLlama/expected/archive/v1.3.1.tar.gz";
            sha256 = "9a04f4f472fbb5c30bf60402f1ca626c4a76987f867978d0b8a35d7ab3fb8fe7";
          };
          patch = pkgs.fetchurl {
            url = "https://wrapdb.mesonbuild.com/v2/tl-expected_1.3.1-1/get_patch";
            sha256 = "91cfeae04ba6ea05792e68a37781236a7045b9e2e4e0c8b7093fd8c3e43b0bad";
          };
        };
        tl-optional = {
          dir = "optional-1.1.0";
          src = pkgs.fetchurl {
            url = "https://github.com/TartanLlama/optional/archive/refs/tags/v1.1.0.tar.gz";
            sha256 = "88ece79f3de5ccaec4191951a222f95cc80c4381dafd3163bdb1ff87cedf3118";
          };
          patch = pkgs.fetchurl {
            url = "https://wrapdb.mesonbuild.com/v2/tl-optional_1.1.0-1/get_patch";
            sha256 = "b64e2a89e44279074d845de4fce85151a27ce65298849e87f6069a77967d4eb7";
          };
        };
      };

      # Build the shell commands that stage each subproject's source (and,
      # if present, unzip its wrapdb "patch" overlay on top) into
      # subprojects/<dir>, exactly like `meson subprojects download` would.
      stageSubprojects = lib.concatStrings (lib.mapAttrsToList
        (name: sp: ''
          mkdir -p "subprojects/${sp.dir}"
          tar xf ${sp.src} -C subprojects --strip-components=0
          ${lib.optionalString (sp ? patch) ''
            unzip -o -q ${sp.patch} -d "subprojects/${sp.dir}"
          ''}
        '') subprojects);
    in {
      packages.${system}.default =
        with pkgs;
        stdenv.mkDerivation {
          name = "mu4e";
          src = self;

          nativeBuildInputs = [
            pkg-config
            meson
            ninja
            texinfo
            emacs
            python3
            cmake
            cld2
            unzip
          ];

          buildInputs = [ glib gmime3 xapian ];

          postPatch = stageSubprojects + ''
            # Scripts vendored via fetchurl (e.g. CLI11's scripts/ExtractVersion.py)
            # keep their original #!/usr/bin/env python3 shebang, which doesn't
            # resolve inside the Nix build sandbox. patchShebangs rewrites them
            # to point at the python3 in nativeBuildInputs.
            patchShebangs subprojects
          '';

          mesonFlags = [
            # "--debug"
            "-Dscm=disabled"
            "-Dreadline=disabled"
            "-Demacs=${emacs}/bin/emacs"
            # CLI11's own meson.build pulls in a catch2 subproject for its
            # test suite. We only consume CLI11 as a library, so disable its
            # tests option to avoid needing to vendor catch2 as well.
            "-Dcli11:tests=disabled"
          ];

          # preConfigure = ''
          #   echo "=== DEBUG: Environment before meson configure ==="
          #   echo "PWD: $(pwd)"
          #   echo "Python version:"
          #   python3 --version || echo "python3 not available"
          #   echo "Python path:"
          #   #which python3 || echo "python3 not in PATH"
          #   echo "PATH: $PATH"
          #   echo "Meson version:"
          #   meson --version
          #   echo "Available files in current directory:"
          #   ls -la
          #   echo "Checking for Python scripts:"
          #   find . -name "*.py" -type f | head -10
          #   echo "=============================================="
          # '';

          meta = with lib; {
            description = "Email indexer and Emacs client (mu4e)";
            longDescription = ''
              mu is a tool for dealing with email messages stored in the
              Maildir-format. mu's purpose in life is to help you to quickly find the
              messages you need; in addition, it allows you to view messages, extract
              attachments, create new maildirs, and so on.

              mu4e is an Emacs-based e-mail client that uses mu as its back-end.
            '';
            license = licenses.gpl3Plus;
            homepage = "https://www.djcbsoftware.nl/code/mu/";
            changelog = "https://github.com/djcb/mu/blob/v${version}/NEWS.org";
            maintainers = with maintainers; [ antono chvp peterhoeg ];
            platforms = platforms.unix;
            mainProgram = "mu";
          };
        };
    };
}