#include <gtest/gtest.h>

#include <XCEngine/Components/CameraComponent.h>
#include <XCEngine/Components/LightComponent.h>
#include <XCEngine/Rendering/Planning/SceneRenderRequestPlanner.h>
#include <XCEngine/Scene/Scene.h>

using namespace XCEngine::Components;
using namespace XCEngine::Rendering;

namespace {

RenderContext CreateValidContext() {
    RenderContext context;
    context.device = reinterpret_cast<XCEngine::RHI::RHIDevice*>(1);
    context.commandList = reinterpret_cast<XCEngine::RHI::RHICommandList*>(1);
    context.commandQueue = reinterpret_cast<XCEngine::RHI::RHICommandQueue*>(1);
    return context;
}

} // namespace

TEST(SceneRenderRequestPlanner_Test, FallsBackToSceneCamerasWhenOverrideCameraIsNotUsable) {
    Scene scene("SceneRenderRequestPlannerOverrideFallback");

    GameObject* overrideObject = scene.CreateGameObject("Override");
    auto* overrideCamera = overrideObject->AddComponent<CameraComponent>();
    overrideCamera->SetDepth(-10.0f);
    overrideCamera->SetEnabled(false);

    GameObject* sceneCameraObject = scene.CreateGameObject("SceneCamera");
    auto* sceneCamera = sceneCameraObject->AddComponent<CameraComponent>();
    sceneCamera->SetDepth(3.0f);

    SceneRenderRequestPlanner planner;
    const std::vector<CameraComponent*> cameras = planner.CollectCameras(scene, overrideCamera);

    ASSERT_EQ(cameras.size(), 1u);
    EXPECT_EQ(cameras[0], sceneCamera);
}

TEST(SceneRenderRequestPlanner_Test, UsesOverrideCameraExclusivelyWhenItIsUsable) {
    Scene scene("SceneRenderRequestPlannerOverrideOnly");

    GameObject* overrideObject = scene.CreateGameObject("Override");
    auto* overrideCamera = overrideObject->AddComponent<CameraComponent>();
    overrideCamera->SetDepth(9.0f);

    GameObject* sceneCameraObject = scene.CreateGameObject("SceneCamera");
    auto* sceneCamera = sceneCameraObject->AddComponent<CameraComponent>();
    sceneCamera->SetDepth(-5.0f);

    SceneRenderRequestPlanner planner;
    const std::vector<CameraComponent*> cameras = planner.CollectCameras(scene, overrideCamera);

    ASSERT_EQ(cameras.size(), 1u);
    EXPECT_EQ(cameras[0], overrideCamera);
}

TEST(SceneRenderRequestPlanner_Test, CollectsOnlyUsableSceneCamerasInStableRenderOrder) {
    Scene scene("SceneRenderRequestPlannerCollectScene");

    GameObject* inactiveObject = scene.CreateGameObject("Inactive");
    auto* inactiveCamera = inactiveObject->AddComponent<CameraComponent>();
    inactiveObject->SetActive(false);

    GameObject* highBaseObject = scene.CreateGameObject("HighBase");
    auto* highBase = highBaseObject->AddComponent<CameraComponent>();
    highBase->SetDepth(10.0f);
    highBase->SetStackType(CameraStackType::Base);

    GameObject* firstTieObject = scene.CreateGameObject("FirstTie");
    auto* firstTie = firstTieObject->AddComponent<CameraComponent>();
    firstTie->SetDepth(2.0f);
    firstTie->SetStackType(CameraStackType::Base);

    GameObject* secondTieObject = scene.CreateGameObject("SecondTie");
    auto* secondTie = secondTieObject->AddComponent<CameraComponent>();
    secondTie->SetDepth(2.0f);
    secondTie->SetStackType(CameraStackType::Base);

    GameObject* overlayObject = scene.CreateGameObject("Overlay");
    auto* overlay = overlayObject->AddComponent<CameraComponent>();
    overlay->SetDepth(-10.0f);
    overlay->SetStackType(CameraStackType::Overlay);

    SceneRenderRequestPlanner planner;
    const std::vector<CameraComponent*> cameras = planner.CollectCameras(scene, nullptr);

    (void)inactiveCamera;
    ASSERT_EQ(cameras.size(), 4u);
    EXPECT_EQ(cameras[0], firstTie);
    EXPECT_EQ(cameras[1], secondTie);
    EXPECT_EQ(cameras[2], highBase);
    EXPECT_EQ(cameras[3], overlay);
}

TEST(SceneRenderRequestPlanner_Test, BuildsRequestsAndDropsZeroSizedViewportsWithoutBreakingClearFlow) {
    Scene scene("SceneRenderRequestPlannerBuildRequests");

    GameObject* firstBaseObject = scene.CreateGameObject("FirstBase");
    auto* firstBase = firstBaseObject->AddComponent<CameraComponent>();
    firstBase->SetStackType(CameraStackType::Base);
    firstBase->SetDepth(1.0f);

    GameObject* skippedBaseObject = scene.CreateGameObject("SkippedBase");
    auto* skippedBase = skippedBaseObject->AddComponent<CameraComponent>();
    skippedBase->SetStackType(CameraStackType::Base);
    skippedBase->SetDepth(2.0f);
    skippedBase->SetViewportRect(XCEngine::Math::Rect(0.5f, 0.5f, 0.0f, 1.0f));

    GameObject* overlayObject = scene.CreateGameObject("Overlay");
    auto* overlay = overlayObject->AddComponent<CameraComponent>();
    overlay->SetStackType(CameraStackType::Overlay);
    overlay->SetDepth(3.0f);

    SceneRenderRequestPlanner planner;
    const std::vector<CameraRenderRequest> requests = planner.BuildRequests(
        scene,
        nullptr,
        CreateValidContext(),
        RenderSurface(640, 360));

    ASSERT_EQ(requests.size(), 2u);
    EXPECT_EQ(requests[0].camera, firstBase);
    EXPECT_EQ(requests[0].clearFlags, RenderClearFlags::All);
    EXPECT_EQ(requests[1].camera, overlay);
    EXPECT_EQ(requests[1].clearFlags, RenderClearFlags::Depth);
}

TEST(SceneRenderRequestPlanner_Test, BuildsDirectionalShadowPlanForBaseCameraWhenMainDirectionalLightCastsShadows) {
    Scene scene("SceneRenderRequestPlannerDirectionalShadow");

    GameObject* cameraObject = scene.CreateGameObject("Camera");
    auto* camera = cameraObject->AddComponent<CameraComponent>();
    camera->SetStackType(CameraStackType::Base);
    camera->SetDepth(1.0f);

    GameObject* shadowLightObject = scene.CreateGameObject("ShadowLight");
    auto* shadowLight = shadowLightObject->AddComponent<LightComponent>();
    shadowLight->SetLightType(LightType::Directional);
    shadowLight->SetIntensity(2.5f);
    shadowLight->SetCastsShadows(true);

    SceneRenderRequestPlanner planner;
    const std::vector<CameraRenderRequest> requests = planner.BuildRequests(
        scene,
        nullptr,
        CreateValidContext(),
        RenderSurface(640, 360));

    ASSERT_EQ(requests.size(), 1u);
    const CameraRenderRequest& request = requests[0];
    EXPECT_EQ(request.camera, camera);
    ASSERT_TRUE(request.directionalShadow.IsValid());
    EXPECT_TRUE(request.directionalShadow.enabled);
    EXPECT_EQ(request.directionalShadow.mapWidth, 1024u);
    EXPECT_EQ(request.directionalShadow.mapHeight, 1024u);
    EXPECT_EQ(request.directionalShadow.lightDirection, XCEngine::Math::Vector3::Back());
    EXPECT_GT(request.directionalShadow.focusPoint.z, 0.0f);
    EXPECT_TRUE(request.shadowCaster.hasCameraDataOverride);
    EXPECT_EQ(request.shadowCaster.clearFlags, RenderClearFlags::Depth);
    EXPECT_EQ(request.shadowCaster.cameraDataOverride.viewportWidth, 1024u);
    EXPECT_EQ(request.shadowCaster.cameraDataOverride.viewportHeight, 1024u);
    EXPECT_EQ(request.shadowCaster.cameraDataOverride.clearFlags, RenderClearFlags::Depth);
}

TEST(SceneRenderRequestPlanner_Test, SkipsDirectionalShadowPlanForOverlayCameraWhenBaseCameraExists) {
    Scene scene("SceneRenderRequestPlannerOverlayShadow");

    GameObject* baseCameraObject = scene.CreateGameObject("BaseCamera");
    auto* baseCamera = baseCameraObject->AddComponent<CameraComponent>();
    baseCamera->SetStackType(CameraStackType::Base);
    baseCamera->SetDepth(1.0f);

    GameObject* overlayCameraObject = scene.CreateGameObject("OverlayCamera");
    auto* overlayCamera = overlayCameraObject->AddComponent<CameraComponent>();
    overlayCamera->SetStackType(CameraStackType::Overlay);
    overlayCamera->SetDepth(2.0f);

    GameObject* shadowLightObject = scene.CreateGameObject("ShadowLight");
    auto* shadowLight = shadowLightObject->AddComponent<LightComponent>();
    shadowLight->SetLightType(LightType::Directional);
    shadowLight->SetIntensity(3.0f);
    shadowLight->SetCastsShadows(true);

    SceneRenderRequestPlanner planner;
    const std::vector<CameraRenderRequest> requests = planner.BuildRequests(
        scene,
        nullptr,
        CreateValidContext(),
        RenderSurface(640, 360));

    ASSERT_EQ(requests.size(), 2u);
    EXPECT_EQ(requests[0].camera, baseCamera);
    EXPECT_TRUE(requests[0].directionalShadow.enabled);
    EXPECT_TRUE(requests[0].shadowCaster.hasCameraDataOverride);

    EXPECT_EQ(requests[1].camera, overlayCamera);
    EXPECT_FALSE(requests[1].directionalShadow.enabled);
    EXPECT_FALSE(requests[1].shadowCaster.hasCameraDataOverride);
}

TEST(SceneRenderRequestPlanner_Test, AppliesConfiguredDirectionalShadowPlanningSettings) {
    Scene scene("SceneRenderRequestPlannerCustomDirectionalShadow");

    GameObject* cameraObject = scene.CreateGameObject("Camera");
    auto* camera = cameraObject->AddComponent<CameraComponent>();
    camera->SetStackType(CameraStackType::Base);
    camera->SetDepth(1.0f);
    camera->SetProjectionType(CameraProjectionType::Perspective);
    camera->SetNearClipPlane(0.3f);
    camera->SetFarClipPlane(100.0f);

    GameObject* shadowLightObject = scene.CreateGameObject("ShadowLight");
    auto* shadowLight = shadowLightObject->AddComponent<LightComponent>();
    shadowLight->SetLightType(LightType::Directional);
    shadowLight->SetCastsShadows(true);

    SceneRenderRequestPlanner planner;
    DirectionalShadowPlanningSettings settings = {};
    settings.mapDimension = 2048u;
    settings.minFocusDistance = 12.0f;
    settings.maxFocusDistance = 12.0f;
    settings.perspectiveFocusFactor = 0.01f;
    settings.minDepthRange = 80.0f;
    settings.sampling.receiverDepthBias = 0.0025f;
    settings.sampling.normalBiasScale = 2.0f;
    settings.sampling.shadowStrength = 0.75f;
    settings.casterBias.depthBiasFactor = 2.5f;
    settings.casterBias.depthBiasUnits = 4;
    planner.SetDirectionalShadowPlanningSettings(settings);

    const std::vector<CameraRenderRequest> requests = planner.BuildRequests(
        scene,
        nullptr,
        CreateValidContext(),
        RenderSurface(640, 360));

    ASSERT_EQ(requests.size(), 1u);
    const CameraRenderRequest& request = requests[0];
    ASSERT_TRUE(request.directionalShadow.IsValid());
    EXPECT_EQ(request.directionalShadow.mapWidth, 2048u);
    EXPECT_EQ(request.directionalShadow.mapHeight, 2048u);
    EXPECT_EQ(request.shadowCaster.cameraDataOverride.viewportWidth, 2048u);
    EXPECT_EQ(request.shadowCaster.cameraDataOverride.viewportHeight, 2048u);
    EXPECT_GE(request.directionalShadow.focusPoint.z, 6.0f);
    EXPECT_LE(request.directionalShadow.focusPoint.z, 6.3f);
    EXPECT_FLOAT_EQ(request.directionalShadow.sampling.receiverDepthBias, 0.0025f);
    EXPECT_FLOAT_EQ(request.directionalShadow.sampling.normalBiasScale, 2.0f);
    EXPECT_FLOAT_EQ(request.directionalShadow.sampling.shadowStrength, 0.75f);
    EXPECT_FLOAT_EQ(request.directionalShadow.casterBias.depthBiasFactor, 2.5f);
    EXPECT_EQ(request.directionalShadow.casterBias.depthBiasUnits, 4);
    EXPECT_GE(
        request.directionalShadow.farClipPlane - request.directionalShadow.nearClipPlane,
        80.0f);
}

TEST(SceneRenderRequestPlanner_Test, SanitizesInvalidDirectionalShadowPlanningSettings) {
    SceneRenderRequestPlanner planner;

    DirectionalShadowPlanningSettings invalidSettings = {};
    invalidSettings.mapDimension = 0u;
    invalidSettings.minFocusDistance = -1.0f;
    invalidSettings.maxFocusDistance = 0.0f;
    invalidSettings.perspectiveFocusFactor = 0.0f;
    invalidSettings.orthographicFocusFactor = -2.0f;
    invalidSettings.minDepthRange = 0.0f;
    invalidSettings.boundsPadding = -1.0f;
    invalidSettings.minDepthPadding = -3.0f;
    invalidSettings.sampling.receiverDepthBias = -0.5f;
    invalidSettings.sampling.normalBiasScale = -2.0f;
    invalidSettings.sampling.shadowStrength = 3.0f;
    invalidSettings.casterBias.depthBiasFactor = -1.0f;
    invalidSettings.casterBias.depthBiasUnits = -6;
    planner.SetDirectionalShadowPlanningSettings(invalidSettings);

    const DirectionalShadowPlanningSettings& settings =
        planner.GetDirectionalShadowPlanningSettings();
    EXPECT_EQ(settings.mapDimension, 1024u);
    EXPECT_FLOAT_EQ(settings.minFocusDistance, 5.0f);
    EXPECT_FLOAT_EQ(settings.maxFocusDistance, 64.0f);
    EXPECT_FLOAT_EQ(settings.perspectiveFocusFactor, 1.0f);
    EXPECT_FLOAT_EQ(settings.orthographicFocusFactor, 2.0f);
    EXPECT_FLOAT_EQ(settings.minDepthRange, 20.0f);
    EXPECT_FLOAT_EQ(settings.boundsPadding, 1.0f);
    EXPECT_FLOAT_EQ(settings.minDepthPadding, 2.0f);
    EXPECT_FLOAT_EQ(settings.sampling.receiverDepthBias, 0.0010f);
    EXPECT_FLOAT_EQ(settings.sampling.normalBiasScale, 2.0f);
    EXPECT_FLOAT_EQ(settings.sampling.shadowStrength, 1.0f);
    EXPECT_FLOAT_EQ(settings.casterBias.depthBiasFactor, 2.5f);
    EXPECT_EQ(settings.casterBias.depthBiasUnits, 4);
}