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#include "ShadowMapBatchedQueue.h"
#include "Define.h"
#include "InstancedBuffer.h"
#include "PipelineSceneData.h"
#include "PipelineStateManager.h"
#include "RenderInstancedQueue.h"
#include "SceneCulling.h"
#include "forward/ForwardPipeline.h"
#include "gfx-base/GFXCommandBuffer.h"
#include "gfx-base/GFXDevice.h"
#include "scene/Camera.h"
#include "scene/DirectionalLight.h"
#include "scene/Shadow.h"
#include "scene/SpotLight.h"
#include "shadow/CSMLayers.h"

namespace cc {
namespace pipeline {

ShadowMapBatchedQueue::ShadowMapBatchedQueue(RenderPipeline *pipeline)
: _phaseID(getPhaseID("shadow-caster")) {
    _pipeline = pipeline;
    _instancedQueue = ccnew RenderInstancedQueue;
}

ShadowMapBatchedQueue::~ShadowMapBatchedQueue() = default;

void ShadowMapBatchedQueue::gatherLightPasses(const scene::Camera *camera, const scene::Light *light, gfx::CommandBuffer *cmdBuffer, uint32_t level) {
    clear();

    const PipelineSceneData *sceneData = _pipeline->getPipelineSceneData();
    const scene::Shadows *shadowInfo = sceneData->getShadows();
    const CSMLayers *csmLayers = sceneData->getCSMLayers();
    if (light && shadowInfo->isEnabled() && shadowInfo->getType() == scene::ShadowType::SHADOW_MAP) {
        switch (light->getType()) {
            case scene::LightType::DIRECTIONAL: {
                const auto *dirLight = static_cast<const scene::DirectionalLight *>(light);
                if (shadowInfo->isEnabled() && shadowInfo->getType() == scene::ShadowType::SHADOW_MAP) {
                    if (dirLight->isShadowEnabled()) {
                        ShadowTransformInfo *layer;
                        if (dirLight->isShadowFixedArea()) {
                            layer = csmLayers->getSpecialLayer();
                        } else {
                            layer = csmLayers->getLayers()[level];
                        }
                        bool isCullingEnable = camera->isCullingEnabled();
                        if (isCullingEnable) {
                            shadowCulling(_pipeline, camera, layer);
                        }
                        const RenderObjectList &dirShadowObjects = layer->getShadowObjects();
                        for (const auto &ro : dirShadowObjects) {
                            add(ro.model);
                        }
                    }
                }
            } break;
            case scene::LightType::SPOT: {
                const auto *spotLight = static_cast<const scene::SpotLight *>(light);
                const RenderObjectList &castShadowObjects = csmLayers->getCastShadowObjects();
                if (spotLight->isShadowEnabled()) {
                    const auto visibility = spotLight->getVisibility();
                    geometry::AABB ab;
                    for (const auto &ro : castShadowObjects) {
                        const auto *model = ro.model;
                        if ((visibility & model->getNode()->getLayer()) != model->getNode()->getLayer() || !model->isEnabled() || !model->isCastShadow() || !model->getNode()) {
                            continue;
                        }
                        if (model->getWorldBounds()) {
                            if (model->getWorldBounds()->aabbFrustum(spotLight->getFrustum())) {
                                add(model);
                            }
                        }
                    }
                }
            } break;
            default:
                break;
        }

        _instancedQueue->uploadBuffers(cmdBuffer);
    }
}

void ShadowMapBatchedQueue::clear() {
    _subModels.clear();
    _shaders.clear();
    _passes.clear();
    if (_instancedQueue) _instancedQueue->clear();
}

void ShadowMapBatchedQueue::add(const scene::Model *model) {
    for (const auto &subModel : model->getSubModels()) {
        const auto shadowPassIdx = getShadowPassIndex(subModel);
        if (shadowPassIdx == -1) {
            continue;
        }

        const auto *pass = subModel->getPass(shadowPassIdx);
        const auto batchingScheme = pass->getBatchingScheme();

        if (batchingScheme == scene::BatchingSchemes::INSTANCING) {
            auto *instancedBuffer = subModel->getPass(shadowPassIdx)->getInstancedBuffer();
            instancedBuffer->merge(subModel, shadowPassIdx);
            _instancedQueue->add(instancedBuffer);
        } else { // standard draw
            _subModels.emplace_back(subModel);
            _shaders.emplace_back(subModel->getShader(shadowPassIdx));
            _passes.emplace_back(pass);
        }
    }
}

void ShadowMapBatchedQueue::recordCommandBuffer(gfx::Device *device, gfx::RenderPass *renderPass, gfx::CommandBuffer *cmdBuffer) const {
    _instancedQueue->recordCommandBuffer(device, renderPass, cmdBuffer);

    for (size_t i = 0; i < _subModels.size(); i++) {
        const auto *const subModel = _subModels[i];
        auto *const shader = _shaders[i];
        const auto *pass = _passes[i];
        auto *const ia = subModel->getInputAssembler();
        auto *const pso = PipelineStateManager::getOrCreatePipelineState(pass, shader, ia, renderPass);

        cmdBuffer->bindPipelineState(pso);
        cmdBuffer->bindDescriptorSet(materialSet, pass->getDescriptorSet());
        cmdBuffer->bindDescriptorSet(localSet, subModel->getDescriptorSet());
        cmdBuffer->bindInputAssembler(ia);
        cmdBuffer->draw(ia);
    }
}

void ShadowMapBatchedQueue::destroy() {
    CC_SAFE_DELETE(_instancedQueue)
}

int ShadowMapBatchedQueue::getShadowPassIndex(const scene::SubModel *subModel) const {
    int i = 0;
    for (const auto &pass : *(subModel->getPasses())) {
        if (pass->getPhase() == _phaseID) {
            return i;
        }
        ++i;
    }
    return -1;
}

} // namespace pipeline
} // namespace cc