{
  description = "intel-hard-graphics / clvk development";
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";

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

      # HD 4000 (Gen7) PCI ID: 8086:0166
      pciId = "8086:0166";
      defaultClvkBuildDir = "/home/elars/ProjectsHDD/Drivers/clvk/build";

      commonBuildInputs = with pkgs; [
        llvmPackages_21.clang-unwrapped
        llvmPackages_21.llvm.dev
        llvmPackages_21.libclang
        llvmPackages_21.bintools
        python3Packages.packaging
        python3Packages.pyyaml
        python3Packages.mako
        python3
        cargo
        meson
        ninja
        pkg-config
        spirv-llvm-translator
        spirv-tools
        rust-bindgen
        rustc
        vkmark
        vulkan-headers
        vulkan-loader
        vulkan-tools
        shaderc
        libpciaccess
        opencl-headers
        libclc
        bison
        flex
        libdrm
        libelf
        expat
        zlib
        zstd
        libx11
        ocl-icd
        libxcb
        cmake
        libxext
        libxfixes
        libxrandr
        libxshmfence
        wayland
        wayland-protocols
        wayland-scanner
        xorgproto
        xorg.libXxf86vm
        xorg.xcbutilkeysyms
        (python3.withPackages (
          ps: with ps; [
            pyopencl
            opencv4
            numpy
          ]
        ))
        clinfo
        strace
        clpeak
        pocl
        gdb
      ];

      commonShellVars = ''
        export LIBRARY_PATH=${pkgs.llvmPackages_21.clang-unwrapped.lib}/lib:$LIBRARY_PATH
        export LIBCLANG_PATH=${pkgs.llvmPackages_21.libclang.lib}/lib
        export BINDGEN_EXTRA_CLANG_ARGS="-I${pkgs.llvmPackages_21.clang-unwrapped}/lib/clang/21/include"
        export C_INCLUDE_PATH=${pkgs.opencl-headers}/include:$C_INCLUDE_PATH
        export LIBRARY_PATH=${pkgs.ocl-icd}/lib:$LIBRARY_PATH
        export LD_LIBRARY_PATH="${pkgs.vulkan-loader}/lib:$LD_LIBRARY_PATH"
      '';

      # 32-bit (i686) build için: L4D2 gibi 32-bit oyunlarla test amaçlı.
      # clvk/rusticl/OpenCL burada yok — sadece hasvk (vulkan_hasvk) + crocus
      # için gereken Vulkan/GL/WSI kütüphaneleri, i686 varyantlarıyla.
      pkgs32 = pkgs.pkgsi686Linux;

      i686BuildInputs = with pkgs32; [
        libdrm
        libelf
        libpciaccess
        expat
        zlib
        zstd
        libx11
        libxcb
        libxext
        libxfixes
        libxrandr
        libxshmfence
        wayland
        wayland-protocols
        xorgproto
        xorg.libXxf86vm
        xorg.xcbutilkeysyms
        vulkan-headers
        vulkan-loader
        llvmPackages_21.llvm.dev
        llvmPackages_21.clang-unwrapped
        llvmPackages_21.libclang
        spirv-llvm-translator
        spirv-tools
        libclc
        # crocus + hasvk (with_driver_using_cl) libclc'ye hard-dependency,
        # rusticl/opencl kapalı olsa bile gerekiyor
      ];

      # Build araçları (meson/ninja/python/bison/flex/pkg-config vs.) i686'da
      # da bulunur ama host mimarisinde çalıştırılmaları yeterli; yine de
      # pkgsi686Linux'tan almak pkg-config'in .pc arama yollarını tutarlı
      # tutar. cmake/rust burada gerekmiyor (clvk 32-bit hedefi değil).
      i686NativeBuildInputs = with pkgs32; [
        meson
        ninja
        pkg-config
        python3
        python3Packages.packaging
        python3Packages.pyyaml
        python3Packages.mako
        bison
        flex
        wayland-scanner
      ];
    in
    {
      devShells.${system} = {
        # nix develop = intel-hard-graphics shell
        default = pkgs.mkShell {
          buildInputs = commonBuildInputs;
          shellHook = ''
            ${commonShellVars}
            export LD_LIBRARY_PATH=$PWD/build/src/gallium/targets/rusticl:$LD_LIBRARY_PATH
            export RUSTICL_ENABLE=crocus

            mkdir -p $PWD/.icd-vendors
            ln -sf $PWD/build/src/gallium/targets/rusticl/rusticl.icd $PWD/.icd-vendors/rusticl.icd
            ln -sf ${pkgs.pocl}/etc/OpenCL/vendors/pocl.icd $PWD/.icd-vendors/pocl.icd
            export OCL_ICD_VENDORS=$PWD/.icd-vendors

            echo "=== intel-hard-graphics ==="
            echo "OCL_ICD_VENDORS=$OCL_ICD_VENDORS"
            echo "RUSTICL_ENABLE=$RUSTICL_ENABLE"
            echo ""
          '';
        };
        # nix develop .#clvk = clvk shell
        clvk = pkgs.mkShell {
          buildInputs = commonBuildInputs;
          shellHook = ''
            ${commonShellVars}

            CLVK_BUILD_DIR="''${CLVK_BUILD_DIR:-${defaultClvkBuildDir}}"

            if [ ! -d "$CLVK_BUILD_DIR" ]; then
              echo "UYARI: clvk build dizini bulunamadi: $CLVK_BUILD_DIR"
              echo "CLVK_BUILD_DIR ortam degiskeniyle dogru yolu ver, ornek:"
              echo "  CLVK_BUILD_DIR=/gercek/yol nix develop .#clvk"
            else
              export LD_LIBRARY_PATH="$CLVK_BUILD_DIR:$LD_LIBRARY_PATH"
            fi

            export MESA_VK_DEVICE_SELECT="${pciId}"

            echo "=== clvk ==="
            echo "CLVK_BUILD_DIR=$CLVK_BUILD_DIR"
            echo "MESA_VK_DEVICE_SELECT=$MESA_VK_DEVICE_SELECT"
            echo ""
          '';
        };
        # nix develop .#i686 = 32-bit hasvk/crocus build shell (L4D2 testi için)
        i686 = pkgs32.mkShell {
          buildInputs = i686BuildInputs;
          nativeBuildInputs = i686NativeBuildInputs;
          shellHook = ''
            export MESA_VK_DEVICE_SELECT="${pciId}"

            echo "=== intel-hard-graphics (i686 / 32-bit) ==="
            echo "CC=$CC"
            echo "meson setup build32 --buildtype=debugoptimized \\"
            echo "  -Dgallium-drivers=crocus -Dvulkan-drivers=intel_hasvk \\"
            echo "  -Dplatforms=x11 -Degl=disabled -Dglx=disabled -Dgbm=disabled \\"
            echo "  -Dopengl=false -Dgles1=disabled -Dgles2=disabled \\"
            echo "  -Dgallium-rusticl=false -Dmicrosoft-clc=disabled -Dllvm=enabled"
            echo ""
          '';
        };
      };
    };
}