frank-nix/packages/affinity-thumbnailer-kde/flake.nix

{
  description = "Thumbnailer for Affinity files (.afpub, .afdesign, .afphoto, .af, .afpackage) on KDE Plasma / freedesktop";

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

  outputs =
    { self, nixpkgs }:
    let
      systems = [
        "x86_64-linux"
        "aarch64-linux"
      ];
      forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f nixpkgs.legacyPackages.${system});
    in
    {
      packages = forAllSystems (pkgs: {
        default = self.packages.${pkgs.stdenv.hostPlatform.system}.affinity-thumbnailer;

        affinity-thumbnailer = pkgs.stdenv.mkDerivation {
          pname = "affinity-thumbnailer";
          version = "0.1.0";

          # Don't pull source from GitHub — we build everything from inline content
          src = pkgs.runCommand "affinity-thumbnailer-src" { } ''
            mkdir -p $out
          '';

          nativeBuildInputs = [ pkgs.makeWrapper ];

          # Runtime dependencies
          buildInputs = [ pkgs.python3 ];

          dontConfigure = true;
          dontBuild = true;

          installPhase = ''
            runHook preInstall

            # --- 1. Install the Python thumbnailer script ---
            mkdir -p $out/bin
            cat > $out/bin/affinity-thumbnailer << 'PYEOF'
            #!/usr/bin/env python3
            """Extract embedded PNG thumbnails from Affinity files (.afpub, .afdesign, .afphoto, .af, .afpackage)."""

            import argparse
            import os
            import sys

            PNG_SIGNATURE = b"\x89PNG"
            PNG_IEND = b"IEND"
            SUPPORTED_EXTENSIONS = {".afpub", ".afdesign", ".afphoto", ".af", ".afpackage"}


            def find_png(data: bytes) -> bytes | None:
                """Find and extract the first complete PNG from binary data."""
                sig_offset = data.find(PNG_SIGNATURE)
                if sig_offset == -1:
                    return None

                iend_offset = data.find(PNG_IEND, sig_offset)
                if iend_offset == -1:
                    return None

                png_end = iend_offset + len(PNG_IEND) + 4
                return data[sig_offset:png_end]


            def extract_thumbnail(filepath: str) -> bytes | None:
                """Read a file and extract its embedded PNG thumbnail."""
                ext = os.path.splitext(filepath)[1].lower()
                if ext not in SUPPORTED_EXTENSIONS:
                    print(
                        f"Error: unsupported extension '{ext}'. "
                        f"Supported: {', '.join(sorted(SUPPORTED_EXTENSIONS))}",
                        file=sys.stderr,
                    )
                    return None

                if not os.path.isfile(filepath):
                    print(f"Error: file not found: {filepath}", file=sys.stderr)
                    return None

                with open(filepath, "rb") as f:
                    data = f.read()

                return find_png(data)


            def main() -> None:
                parser = argparse.ArgumentParser(
                    description="Extract embedded PNG thumbnail from Affinity files."
                )
                parser.add_argument("input", help="Input Affinity file (.afpub, .afdesign, .afphoto, .af, .afpackage)")
                parser.add_argument(
                    "output",
                    nargs="?",
                    default=None,
                    help="Output PNG file (default: stdout)",
                )
                args = parser.parse_args()

                png_data = extract_thumbnail(args.input)
                if png_data is None:
                    print("Error: no embedded PNG thumbnail found.", file=sys.stderr)
                    sys.exit(1)

                if args.output:
                    with open(args.output, "wb") as f:
                        f.write(png_data)
                    print(f"Thumbnail saved: {args.output} ({len(png_data)} bytes)")
                else:
                    sys.stdout.buffer.write(png_data)


            if __name__ == "__main__":
                main()
            PYEOF
            chmod +x $out/bin/affinity-thumbnailer

            # Wrap so it finds python3 in NixOS
            wrapProgram $out/bin/affinity-thumbnailer \
              --prefix PATH : ${pkgs.lib.makeBinPath [ pkgs.python3 ]}

            # --- 2. Install the .thumbnailer freedesktop entry ---
            mkdir -p $out/share/thumbnailers
            cat > $out/share/thumbnailers/affinity.thumbnailer << EOF
            [Thumbnailer Entry]
            TryExec=$out/bin/affinity-thumbnailer
            Exec=$out/bin/affinity-thumbnailer %i %o
            MimeType=application/affinity-publisher;application/affinity-designer;application/affinity-photo;application/affinity-v3;application/affinity-package;
            EOF

            # --- 3. Install MIME type definitions ---
            mkdir -p $out/share/mime/packages
            cat > $out/share/mime/packages/application-affinity.xml << 'MIMEXML'
            <?xml version="1.0" encoding="UTF-8"?>
            <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
              <mime-type type="application/affinity-publisher">
                <comment>Affinity File</comment>
                <glob pattern="*.afpub"/>
              </mime-type>
              <mime-type type="application/affinity-designer">
                <comment>Affinity File</comment>
                <glob pattern="*.afdesign"/>
              </mime-type>
              <mime-type type="application/affinity-photo">
                <comment>Affinity File</comment>
                <glob pattern="*.afphoto"/>
              </mime-type>
              <mime-type type="application/affinity-v3">
                <comment>Affinity File</comment>
                <glob pattern="*.af"/>
              </mime-type>
              <mime-type type="application/affinity-package">
                <comment>Affinity File</comment>
                <glob pattern="*.afpackage"/>
              </mime-type>
            </mime-info>
            MIMEXML

            runHook postInstall
          '';

          meta = with pkgs.lib; {
            description = "Thumbnailer for Affinity files on KDE Plasma / freedesktop";
            homepage = "https://github.com/Nczer/Affinity-thumbnailer-KDE-plasma";
            license = licenses.mit; # No license specified in the repo
            platforms = platforms.linux;
          };
        };
      });

      # --- NixOS module for easy integration ---
      nixosModules.default =
        {
          pkgs,
          config,
          lib,
          ...
        }:
        {
          options.services.affinity-thumbnailer = {
            enable = lib.mkEnableOption "Affinity file thumbnailer for KDE Plasma / freedesktop";
          };

          config = lib.mkIf config.services.affinity-thumbnailer.enable {
            environment.systemPackages = [
              self.packages.${pkgs.stdenv.hostPlatform.system}.default
            ];

            # Make sure thumbnailer and MIME directories are linked
            environment.pathsToLink = [
              "/share/thumbnailers"
              "/share/mime"
            ];
          };
        };
    };
}