# Usage:
#   - Shell: `nix develop`
#   - Direnv (https://direnv.net/): `.envrc` content of `use flake`
#   - Build: `nix build`
#   - Run:   `nix run`

{
  description = "Slack Local Reader";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs =
    { self
    , nixpkgs
    , flake-utils
    ,
    }:
    flake-utils.lib.eachDefaultSystem (
      system:
      let
        pkgs = nixpkgs.legacyPackages.${system};
        python = pkgs.python312;

        # ── Python Dependency Overrides ──────────────────────────────
        #
        # dfindexeddb pins python-snappy==0.6.1 and zstd==1.5.5.1.
        # nixpkgs ships newer versions, so we build the exact pins
        # from PyPI source tarballs.

        pythonPackages = python.pkgs;

        python-snappy = pythonPackages.buildPythonPackage rec {
          pname = "python-snappy";
          version = "0.6.1";
          format = "setuptools";

          src = pkgs.fetchurl {
            url = "https://files.pythonhosted.org/packages/98/7a/44a24bad98335b2c72e4cadcdecf79f50197d1bab9f22f863a274f104b96/python-snappy-0.6.1.tar.gz";
            hash = "sha256-tqEHqwYgasxTWdTFYyvZsi1EhwKnmzFpsMYuD7gIuyo=";
          };

          buildInputs = [ pkgs.snappy ];

          # Tests require snappy test fixtures not present in sdist
          doCheck = false;
        };

        zstd-python = pythonPackages.buildPythonPackage rec {
          pname = "zstd";
          version = "1.5.5.1";
          format = "setuptools";

          src = pkgs.fetchurl {
            url = "https://files.pythonhosted.org/packages/source/z/zstd/zstd-1.5.5.1.tar.gz";
            hash = "sha256-HvmAq/Dh4HKwKNLXbvlbR2YyZRyWIlzzC2Gcbu9iVnI=";
          };

          # Bundled C sources — no external zstd library needed
          doCheck = false;
        };

        dfindexeddb = pythonPackages.buildPythonPackage rec {
          pname = "dfindexeddb";
          version = "20260210";
          format = "setuptools";

          src = pkgs.fetchurl {
            url = "https://files.pythonhosted.org/packages/source/d/dfindexeddb/dfindexeddb-20260210.tar.gz";
            hash = "sha256-4ahEe4Lpoh0oqGR6kI7J1HEGfvKVEzu3qQ+3ykgFd/Y=";
          };

          propagatedBuildInputs = [
            python-snappy
            zstd-python
          ];

          doCheck = false;
        };

        # ── Slack CLI Package ────────────────────────────────────────

        slack-cli = pythonPackages.buildPythonApplication {
          pname = "slack-cli";
          version = "0.1.0";
          format = "pyproject";

          src = let
            fs = pkgs.lib.fileset;
          in
          fs.toSource {
            root = ./.;
            fileset = fs.unions [
              ./pyproject.toml
              ./slack_cli
            ];
          };

          build-system = [ pythonPackages.setuptools ];

          dependencies = [ dfindexeddb ];

          doCheck = false;

          meta = {
            description = "Read Slack messages from local Chromium IndexedDB cache";
            mainProgram = "slack-cli";
          };
        };
      in
      {
        packages.default = slack-cli;

        devShells.default = pkgs.mkShell {
          packages = with pkgs; [
            python
            uv
            snappy
          ];

          shellHook = ''
            export UV_PYTHON_PREFERENCE=only-system
          '';
        };
      }
    );
}