{ lib
, stdenv
, fetchFromGitHub
, fetchgit
, cmake
, ninja
, pkg-config
, glfw3
, glm
, vulkan-headers
, vulkan-loader
, vulkan-volk
, vulkan-utility-libraries
, vulkan-memory-allocator
, vk-bootstrap
, fmt
, cli11
, glslang
, shader-slang
, simdjson
, patchelf
}:

let
  fs = lib.fileset;
  fastgltf = fetchFromGitHub {
    owner = "spnda";
    repo = "fastgltf";
    rev = "v0.8.0";
    hash = "sha256-nPkVMrve1+04XRpSswBqjlSurliCFBRxR8Zxy4xZ5pE=";
  };
  imgui = fetchgit {
      url = "https://git.alexdelcamp.fr/Alexandre_1a/imgui.git";
      rev = "d7cce3ad5070bbdbbd7a39335c0c1e90071211d0";
      hash = "sha256-2v085YFc17aj96YlOc4Fp8sJUHUmjRU8X54FnuqKrgc=";
  };
in
stdenv.mkDerivation {
  pname = "vulkan-engine";
  version = "1.1.0";
  src = ./.;

  postUnpack = ''
      # include/ peut ne pas exister du tout dans la copie flake
      # (cas de figure ici), donc on le crée.
      mkdir -p $sourceRoot/include

      # On remplace les dossiers vides (ou absents) par les vraies sources
      rm -rf $sourceRoot/include/imgui $sourceRoot/include/CLI11
      cp -r ${imgui}             $sourceRoot/include/imgui

      # Autorise le write sur l'arbre : CMake va générer des fichiers
      chmod -R u+w $sourceRoot
    '';


  nativeBuildInputs = [
    cmake
    ninja
    pkg-config
    glslang
    shader-slang
  ];

  buildInputs = [
    glfw3
    glm
    vulkan-headers
    vulkan-volk
    vulkan-loader
    vulkan-utility-libraries
    vk-bootstrap
    vulkan-memory-allocator
    fmt
    cli11
    simdjson
  ];

  cmakeFlags = [
    "-DCMAKE_BUILD_TYPE=Release"
    "-DCMAKE_EXPORT_COMPILE_COMMANDS=ON"
    "-DFETCHCONTENT_SOURCE_DIR_FASTGLTF=${fastgltf}"
    "-DFETCHCONTENT_FULLY_DISCONNECTED=ON"
  ];

  postFixup = ''
      patchelf --add-rpath ${lib.makeLibraryPath [ vulkan-loader ]} $out/bin/engine
  '';

  installPhase = ''
    runHook preInstall
    mkdir -p $out/bin

    cp engine/engine $out/bin/engine
    cp server/server $out/bin/server

    # Copier les shaders compilés où qu'ils soient
    if [ -d engine/shaders ]; then
      cp -r engine/shaders $out/bin/shaders
    elif [ -d $sourceRoot/engine/shaders ]; then
      # fallback : sources, à compiler ? normalement non
      cp -r $sourceRoot/engine/shaders $out/bin/shaders
    else
      echo "ERREUR : aucun dossier shaders trouvé" >&2
      find . -name "*.spv" >&2
      exit 1
    fi

    [ -d engine/models ]   && cp -r engine/models   $out/bin/models
    [ -d engine/textures ] && cp -r engine/textures $out/bin/textures
    [ -f engine/LICENSE ]  && cp engine/LICENSE     $out/bin/LICENSE

    runHook postInstall
  '';

  meta.mainProgram = "engine";
}