{
  description = "Custom Gitweb Package and FCGI Service Wrapper";

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

  outputs = { self, nixpkgs, ... }:
    let
      systems = [ "x86_64-linux" "aarch64-linux" ];
      forAllSystems = nixpkgs.lib.genAttrs systems;
    in
    {
      packages = forAllSystems (system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
          
          perlDeps = with pkgs.perlPackages; [
            CGI
            HTMLParser
            CGIFast
            FCGI
            FCGIProcManager
            HTMLTagCloud
          ];
        in
        {
          default = pkgs.stdenv.mkDerivation {
            pname = "ps-gitweb";
            version = "1.0.0";
            
            # Assuming source is in the same directory
            src = ./.;

            buildInputs = [ pkgs.perl pkgs.gzip ] ++ perlDeps;

            buildFlags = [ "gitweb" ];

            # 2. The requested postInstall logic
            postInstall = ''
              mkdir -p $out/static
              cp gitweb/gitweb.cgi $out/gitweb.cgi
              cp gitweb/static/git* $out/static/

              # Ensure the file exists (standard gitweb location)
              # If your makefile installs elsewhere, adjust this check.
              if [ -f "$out/gitweb.cgi" ]; then
                
                # Patch gzip path
                sed -i -e "s|'compressor' => \['gzip'|'compressor' => ['${pkgs.gzip}/bin/gzip'|" \
                  $out/gitweb.cgi
                
                # Patch Perl Libs (Injecting dependencies into @INC)
                for p in ${pkgs.lib.concatStringsSep " " perlDeps}; do
                  sed -i -e "/use CGI /i use lib \"$p/${pkgs.perl.libPrefix}\";" \
                    "$out/gitweb.cgi"
                done
              else
                 echo "Warning: gitweb.cgi not found in $out/"
              fi
            '';
          };
        });
    };
}