//
// Created by Marc Rousavy on 21.02.24.
//

#include "RNFEngineImpl.h"

#include "RNFReferences.h"
#include "utils/RNFConverter.h"

#include <filament/Camera.h>
#include <filament/Color.h>
#include <filament/Engine.h>
#include <filament/Fence.h>
#include <filament/IndirectLight.h>
#include <filament/LightManager.h>
#include <filament/RenderableManager.h>
#include <filament/Scene.h>
#include <filament/SwapChain.h>
#include <filament/TransformManager.h>
#include <filament/View.h>
#include <filament/Viewport.h>
#include <utils/Entity.h>
#include <utils/EntityManager.h>

#include <gltfio/Animator.h>
#include <gltfio/MaterialProvider.h>
#include <gltfio/materials/uberarchive.h>

#include <ktxreader/Ktx1Reader.h>

#include <unistd.h>
#include <utility>

namespace margelo {

EngineImpl::EngineImpl(std::shared_ptr<Dispatcher> rendererDispatcher, std::shared_ptr<Engine> engine, float displayRefreshRate,
                       float densityPixelRatio)
    : _engine(engine), _rendererDispatcher(rendererDispatcher), _densityPixelRatio(densityPixelRatio) {

  gltfio::MaterialProvider* _materialProviderPtr =
      gltfio::createUbershaderProvider(engine.get(), UBERARCHIVE_DEFAULT_DATA, UBERARCHIVE_DEFAULT_SIZE);
  _materialProvider = References<gltfio::MaterialProvider>::adoptEngineRef(
      engine, _materialProviderPtr, [](std::shared_ptr<Engine> engine, gltfio::MaterialProvider* provider) {
        Logger::log(TAG, "Destroying material provider...");
        // Note: The materials of the provider are getting destroyed when the scene is destroyed,
        delete provider;
      });

  EntityManager& entityManager = engine->getEntityManager();
  _nameComponentManager = std::make_shared<NameComponentManager>(entityManager);
  gltfio::AssetConfiguration assetConfig{
      .engine = engine.get(), .materials = _materialProvider.get(), .names = _nameComponentManager.get()};
  gltfio::AssetLoader* assetLoaderPtr = gltfio::AssetLoader::create(assetConfig);
  auto nameComponentManager = _nameComponentManager; // The assetLoader holds a reference to the nameComponentManager
  _assetLoader = References<gltfio::AssetLoader>::adoptEngineRef(
      engine, assetLoaderPtr, [nameComponentManager, rendererDispatcher](std::shared_ptr<Engine> engine, gltfio::AssetLoader* assetLoader) {
        rendererDispatcher->runAsync([nameComponentManager, assetLoader]() {
          Logger::log(TAG, "Destroying asset loader...");
          gltfio::AssetLoader::destroy(const_cast<gltfio::AssetLoader**>(&assetLoader));
        });
      });

  filament::gltfio::ResourceConfiguration resourceConfig{.engine = engine.get(), .normalizeSkinningWeights = true};
  auto* resourceLoaderPtr = new filament::gltfio::ResourceLoader(resourceConfig);
  // Add texture providers to the resource loader
  auto* stbProvider = filament::gltfio::createStbProvider(engine.get());
  auto* ktx2Provider = filament::gltfio::createKtx2Provider(engine.get());
  resourceLoaderPtr->addTextureProvider("image/jpeg", stbProvider);
  resourceLoaderPtr->addTextureProvider("image/png", stbProvider);
  resourceLoaderPtr->addTextureProvider("image/ktx2", ktx2Provider);

  _resourceLoader = References<gltfio::ResourceLoader>::adoptEngineRef(
      engine, resourceLoaderPtr,
      [stbProvider, ktx2Provider, rendererDispatcher](std::shared_ptr<Engine> engine, gltfio::ResourceLoader* resourceLoader) {
        Logger::log(TAG, "Destroying resource loader...");
        resourceLoader->evictResourceData();
        delete resourceLoader;
        delete stbProvider;
        delete ktx2Provider;
      });

  // Setup filament:
  _renderer = createRenderer(displayRefreshRate);
  _scene = createScene();
  _view = createView();
  _camera = createCamera();

  _view->setScene(_scene.get());
  _view->setCamera(_camera.get());
}

void EngineImpl::setSurfaceProvider(std::shared_ptr<SurfaceProvider> surfaceProvider) {
  Logger::log(TAG, "Setting surface provider...");

  if (surfaceProvider == nullptr) {
    [[unlikely]];
    throw std::runtime_error("SurfaceProvider cannot be null!");
  }
  _surfaceProvider = surfaceProvider; // Hold a reference to avoid it getting destroyed
  std::shared_ptr<Surface> surface = surfaceProvider->getSurfaceOrNull();
  if (surface != nullptr) {
    surfaceSizeChanged(surface->getWidth(), surface->getHeight());
  }

  auto dispatcher = _rendererDispatcher;
  std::weak_ptr<EngineImpl> weakSelf = shared_from_this();
  SurfaceProvider::Callbacks callback{.onSurfaceCreated =
                                          [dispatcher, weakSelf](std::shared_ptr<Surface> surface) {
                                            dispatcher->runAsync([=]() {
                                              auto sharedThis = weakSelf.lock();
                                              if (sharedThis != nullptr) {
                                                sharedThis->surfaceSizeChanged(surface->getWidth(), surface->getHeight());
                                              }
                                            });
                                          },
                                      .onSurfaceSizeChanged =
                                          [dispatcher, weakSelf](std::shared_ptr<Surface> surface, int width, int height) {
                                            dispatcher->runAsync([=]() {
                                              auto sharedThis = weakSelf.lock();
                                              if (sharedThis != nullptr) {
                                                std::unique_lock lock(sharedThis->_mutex);
                                                Logger::log(TAG, "Updating Surface size...");
                                                sharedThis->surfaceSizeChanged(width, height);
                                                sharedThis->synchronizePendingFrames();
                                              }
                                            });
                                          },
                                      .onSurfaceDestroyed = std::nullopt};
  _surfaceListener = surfaceProvider->addOnSurfaceChangedListener(std::move(callback));
}

void EngineImpl::surfaceSizeChanged(int width, int height) {
  if (width <= 0 || height <= 0) {
    Logger::log(TAG, "(surfaceSizeChanged) Ignoring invalid surface size: %d x %d", width, height);
    return;
  }

  if (_view) {
    _view->setViewport({0, 0, static_cast<uint32_t>(width), static_cast<uint32_t>(height)});
  }
  if (_cameraManipulator) {
    Logger::log(TAG, "(surfaceSizeChanged) Updating viewport size to %d x %d", width, height);
    _cameraManipulator->setViewport(width, height);
  }
}

std::shared_ptr<SwapChain> EngineImpl::createSwapChain(void* nativeWindow, u_int64_t flags = 0) {
  Logger::log(TAG, "Creating swapchain ...");
  auto dispatcher = _rendererDispatcher;
  return References<SwapChain>::adoptEngineRef(_engine, _engine->createSwapChain(nativeWindow, flags),
                                               [dispatcher](std::shared_ptr<Engine> engine, SwapChain* swapChain) {
                                                 dispatcher->runAsync([engine, swapChain]() {
                                                   Logger::log(TAG, "Destroying swapchain...");
                                                   engine->destroy(swapChain);
                                                   // Required to ensure we don't return before Filament is done executing the
                                                   // destroySwapChain command, otherwise Android might destroy the Surface
                                                   // too early
                                                   engine->flushAndWait();
                                                   Logger::log(TAG, "Destroyed swapchain!");
                                                 });
                                               });
}

void EngineImpl::setSwapChain(std::shared_ptr<SwapChain> swapChain) {
  std::unique_lock lock(_mutex);
  Logger::log(TAG, "Setting swapchain...");
  _swapChain = swapChain;
}

std::shared_ptr<Renderer> EngineImpl::createRenderer(float displayRefreshRate) {
  auto dispatcher = _rendererDispatcher;
  std::shared_ptr<Renderer> renderer = References<Renderer>::adoptEngineRef(
      _engine, _engine->createRenderer(), [dispatcher](std::shared_ptr<Engine> engine, Renderer* renderer) {
        dispatcher->runAsync([engine, renderer]() {
          Logger::log(TAG, "Destroying renderer...");
          engine->destroy(renderer);
        });
      });
  renderer->setClearOptions({.clear = true});
  renderer->setDisplayInfo({.refreshRate = displayRefreshRate});
  return renderer;
}

std::shared_ptr<Scene> EngineImpl::createScene() {
  auto materialProvider = _materialProvider;
  auto dispatcher = _rendererDispatcher;
  std::shared_ptr<Scene> scene = References<Scene>::adoptEngineRef(
      _engine, _engine->createScene(), [materialProvider, dispatcher](std::shared_ptr<Engine> engine, Scene* scene) {
        dispatcher->runAsync([materialProvider, engine, scene]() {
          Logger::log(TAG, "Destroying scene...");
          // Destroy all materials that were created by the material provider
          materialProvider->destroyMaterials();
          engine->destroy(scene);
        });
      });

  return scene;
}

std::shared_ptr<View> EngineImpl::createView() {
  auto dispatcher = _rendererDispatcher;
  std::shared_ptr view =
      References<View>::adoptEngineRef(_engine, _engine->createView(), [dispatcher](std::shared_ptr<Engine> engine, View* view) {
        dispatcher->runAsync([engine, view]() {
          Logger::log(TAG, "Destroying view...");
          engine->destroy(view);
        });
      });

  return view;
}

std::shared_ptr<Camera> EngineImpl::createCamera() {
  auto dispatcher = _rendererDispatcher;
  std::shared_ptr<Camera> camera = References<Camera>::adoptEngineRef(_engine, _engine->createCamera(_engine->getEntityManager().create()),
                                                                      [dispatcher](std::shared_ptr<Engine> engine, Camera* camera) {
                                                                        dispatcher->runAsync([engine, camera]() {
                                                                          Logger::log(TAG, "Destroying camera...");
                                                                          EntityManager::get().destroy(camera->getEntity());
                                                                          engine->destroyCameraComponent(camera->getEntity());
                                                                        });
                                                                      });

  const float aperture = 16.0f;
  const float shutterSpeed = 1.0f / 125.0f;
  const float sensitivity = 100.0f;
  camera->setExposure(aperture, shutterSpeed, sensitivity);
  return camera;
}

std::shared_ptr<FilamentAssetWrapper> EngineImpl::loadAsset(std::shared_ptr<FilamentBuffer> modelBuffer) {
  std::unique_lock lock(_mutex);
  std::shared_ptr<ManagedBuffer> buffer = modelBuffer->getBuffer();
  gltfio::FilamentAsset* assetPtr = _assetLoader->createAsset(buffer->getData(), buffer->getSize());

  return makeAssetWrapper(assetPtr);
}

std::shared_ptr<FilamentAssetWrapper> EngineImpl::loadInstancedAsset(std::shared_ptr<FilamentBuffer> modelBuffer, int instanceCount) {
  std::unique_lock lock(_mutex);
  std::shared_ptr<ManagedBuffer> buffer = modelBuffer->getBuffer();
  FilamentInstance* instances[instanceCount]; // Memory managed by the FilamentAsset
  gltfio::FilamentAsset* assetPtr = _assetLoader->createInstancedAsset(buffer->getData(), buffer->getSize(), instances, instanceCount);

  return makeAssetWrapper(assetPtr);
}

std::shared_ptr<FilamentAssetWrapper> EngineImpl::makeAssetWrapper(FilamentAsset* assetPtr) {
  if (assetPtr == nullptr) {
    throw std::runtime_error("Failed to load asset");
  }

  auto assetLoader = _assetLoader;
  auto dispatcher = _rendererDispatcher;
  auto scene = _scene;
  std::shared_ptr<EngineImpl> sharedThis = shared_from_this();
  auto asset =
      References<gltfio::FilamentAsset>::adoptRef(assetPtr, [dispatcher, assetLoader, scene, sharedThis](gltfio::FilamentAsset* asset) {
        dispatcher->runAsync([assetLoader, asset, scene, sharedThis]() {
          std::unique_lock lock(sharedThis->_mutex); // Locking here, so we don't call render while destroying the asset
          Logger::log(TAG, "Destroying asset...");
          scene->removeEntities(asset->getEntities(), asset->getEntityCount());
          assetLoader->destroyAsset(asset);
        });
      });

  // TODO: When supporting loading glTF files with external resources, we need to load the resources here
  //    const char* const* const resourceUris = asset->getResourceUris();
  //    const size_t resourceUriCount = asset->getResourceUriCount();
  _resourceLoader->loadResources(asset.get());

  return std::make_shared<FilamentAssetWrapper>(asset);
}

// Default light is a directional light for shadows + a default IBL
void EngineImpl::setIndirectLight(std::shared_ptr<FilamentBuffer> iblBuffer, std::optional<double> intensity,
                                  std::optional<int> irradianceBands) {
  std::unique_lock lock(_mutex);
  if (!_scene) {
    throw std::runtime_error("Scene not initialized");
  }
  if (!iblBuffer) {
    throw std::runtime_error("IBL buffer is null");
  }
  auto buffer = iblBuffer->getBuffer();
  if (buffer->getSize() == 0) {
    throw std::runtime_error("IBL buffer is empty");
  }

  auto* iblBundle = new image::Ktx1Bundle(buffer->getData(), buffer->getSize());
  Texture* cubemap = ktxreader::Ktx1Reader::createTexture(
      _engine.get(), *iblBundle, false,
      [](void* userdata) {
        auto* bundle = (image::Ktx1Bundle*)userdata;
        delete bundle;
      },
      iblBundle);

  math::float3 harmonics[9];
  iblBundle->getSphericalHarmonics(harmonics);

  IndirectLight::Builder builder = IndirectLight::Builder().reflections(cubemap);
  if (intensity.has_value()) {
    builder.intensity(static_cast<float>(intensity.value()));
  }
  if (irradianceBands.has_value()) {
    builder.irradiance(static_cast<uint8_t>(irradianceBands.value()), harmonics);
  } else {
    builder.irradiance(3, harmonics);
  }

  IndirectLight* _indirectLight = builder.build(*_engine);
  _scene->setIndirectLight(_indirectLight);
}

std::shared_ptr<TransformManagerWrapper> EngineImpl::createTransformManager() {
  std::unique_lock lock(_mutex);
  std::shared_ptr<TransformManagerImpl> transformManagerImpl = std::make_shared<TransformManagerImpl>(_engine);
  return std::make_shared<TransformManagerWrapper>(transformManagerImpl);
}

std::shared_ptr<NameComponentManagerWrapper> EngineImpl::createNameComponentManager() {
  return std::make_shared<NameComponentManagerWrapper>(_nameComponentManager);
}

void EngineImpl::synchronizePendingFrames() {
  // Wait for all pending frames to be processed before returning. This is to
  // avoid a race between the surface being resized before pending frames are
  // rendered into it.
  Fence* fence = _engine->createFence();
  fence->wait(Fence::Mode::FLUSH, Fence::FENCE_WAIT_FOR_EVER);
  _engine->destroy(fence);
}

std::shared_ptr<RenderableManagerWrapper> EngineImpl::createRenderableManager() {
  std::unique_lock lock(_mutex);
  std::shared_ptr<RenderableManagerImpl> renderableManagerImpl = std::make_shared<RenderableManagerImpl>(_engine, _rendererDispatcher);
  return std::make_shared<RenderableManagerWrapper>(renderableManagerImpl);
}

std::shared_ptr<MaterialWrapper> EngineImpl::createMaterial(std::shared_ptr<FilamentBuffer> materialBuffer) {
  std::unique_lock lock(_mutex);
  auto buffer = materialBuffer->getBuffer();
  if (buffer->getSize() == 0) {
    throw std::runtime_error("Material buffer is empty");
  }

  auto sharedThis = shared_from_this();
  auto dispatcher = _rendererDispatcher;
  Material::Builder builder = Material::Builder().package(buffer->getData(), buffer->getSize());
  std::shared_ptr<Material> material = References<Material>::adoptEngineRef(
      _engine, builder.build(*_engine), [dispatcher, sharedThis](std::shared_ptr<Engine> engine, Material* material) {
        dispatcher->runAsync([engine, material, sharedThis]() {
          std::unique_lock lock(sharedThis->_mutex);
          Logger::log(TAG, "Destroying material...");
          engine->destroy(material);
        });
      });

  std::shared_ptr<MaterialImpl> materialImpl = References<MaterialImpl>::adoptEngineRef(
      _engine, new MaterialImpl(material), [dispatcher, sharedThis](std::shared_ptr<Engine> engine, MaterialImpl* pMaterialImpl) {
        dispatcher->runAsync([engine, pMaterialImpl, sharedThis]() {
          Logger::log(TAG, "Destroying MaterialImpl / all material instances...");

          // Iterate over materialWrapper.getInstances() vector and destroy all instances
          for (auto& materialInstanceWrapper : pMaterialImpl->getInstances()) {
            std::unique_lock lock(sharedThis->_mutex);
            MaterialInstance* materialInstance = materialInstanceWrapper->getMaterialInstance();
            // Note: we should only destroy a material instance when no-one is using it anymore
            engine->destroy(materialInstance);
          }

          delete pMaterialImpl;
        });
      });

  return std::make_shared<MaterialWrapper>(materialImpl);
}

std::shared_ptr<LightManagerWrapper> EngineImpl::createLightManager() {
  std::unique_lock lock(_mutex);
  return std::make_shared<LightManagerWrapper>(_engine);
}

void EngineImpl::setAutomaticInstancingEnabled(bool enabled) {
  std::unique_lock lock(_mutex);
  _engine->setAutomaticInstancingEnabled(enabled);
}

void EngineImpl::flushAndWait() {
  std::unique_lock lock(_mutex);
  _engine->flushAndWait();
}

} // namespace margelo