#include <gtest/gtest.h>

#include "Core/EditorContext.h"
#include "Viewport/SceneViewportOverlayBuilder.h"
#include "Viewport/SceneViewportOverlayHandleBuilder.h"
#include "Viewport/SceneViewportOverlayProviders.h"

#include <XCEngine/Components/CameraComponent.h>
#include <XCEngine/Components/LightComponent.h>
#include <XCEngine/Core/Math/Color.h>
#include <XCEngine/Core/Math/Vector3.h>

#include <algorithm>
#include <memory>
#include <vector>

namespace XCEngine::Editor {
namespace {

class MarkerOverlayProvider final : public ISceneViewportOverlayProvider {
public:
    explicit MarkerOverlayProvider(float marker)
        : m_marker(marker) {
    }

    const char* GetName() const override {
        return "MarkerOverlayProvider";
    }

    void AppendOverlay(
        const SceneViewportOverlayBuildContext& context,
        SceneViewportOverlayFrameData& frameData) const override {
        if (!context.IsValid()) {
            return;
        }

        SceneViewportOverlayLinePrimitive& line = frameData.worldLines.emplace_back();
        line.startWorld = Math::Vector3(m_marker, 0.0f, 0.0f);
        line.endWorld = Math::Vector3(m_marker, 1.0f, 0.0f);
        line.color = Math::Color::White();
    }

private:
    float m_marker = 0.0f;
};

SceneViewportOverlayData CreateValidOverlay() {
    SceneViewportOverlayData overlay = {};
    overlay.valid = true;
    overlay.cameraPosition = Math::Vector3::Zero();
    overlay.cameraForward = Math::Vector3::Forward();
    overlay.cameraRight = Math::Vector3::Right();
    overlay.cameraUp = Math::Vector3::Up();
    overlay.verticalFovDegrees = 60.0f;
    overlay.nearClipPlane = 0.1f;
    overlay.farClipPlane = 1000.0f;
    overlay.orbitDistance = 6.0f;
    return overlay;
}

SceneViewportOverlayBuildContext CreateBuildContext(
    EditorContext& context,
    const SceneViewportOverlayData& overlay,
    const std::vector<uint64_t>& selectedObjectIds,
    uint32_t viewportWidth = 1280u,
    uint32_t viewportHeight = 720u,
    const SceneViewportTransformGizmoOverlayState* transformGizmoOverlayState = nullptr) {
    return {
        &context,
        context.GetSceneManager().GetScene(),
        &overlay,
        viewportWidth,
        viewportHeight,
        &selectedObjectIds,
        transformGizmoOverlayState
    };
}

SceneViewportTransformGizmoOverlayState CreateMoveGizmoOverlayState(uint64_t entityId = 99u) {
    SceneViewportTransformGizmoOverlayState state = {};
    state.hasMoveGizmo = true;
    state.moveEntityId = entityId;
    state.moveGizmo.visible = true;

    SceneViewportMoveGizmoHandleDrawData& handle = state.moveGizmo.handles[0];
    handle.axis = SceneViewportGizmoAxis::X;
    handle.start = Math::Vector2(24.0f, 48.0f);
    handle.end = Math::Vector2(104.0f, 48.0f);
    handle.color = Math::Color(0.91f, 0.09f, 0.05f, 1.0f);
    handle.visible = true;

    return state;
}

bool ContainsSpriteKind(
    const SceneViewportOverlayFrameData& frameData,
    SceneViewportOverlaySpriteTextureKind textureKind) {
    return std::any_of(
        frameData.worldSprites.begin(),
        frameData.worldSprites.end(),
        [textureKind](const SceneViewportOverlaySpritePrimitive& sprite) {
            return sprite.textureKind == textureKind;
        });
}

const SceneViewportOverlayLinePrimitive* FindLineStartingAt(
    const SceneViewportOverlayFrameData& frameData,
    const Math::Vector3& position) {
    const auto matchesPosition = [&position](const SceneViewportOverlayLinePrimitive& line) {
        return (line.startWorld - position).SqrMagnitude() <= 1e-4f;
    };

    const auto it = std::find_if(
        frameData.worldLines.begin(),
        frameData.worldLines.end(),
        matchesPosition);
    return it != frameData.worldLines.end() ? &(*it) : nullptr;
}

TEST(SceneViewportOverlayProviderRegistryTest, AppendsProvidersInRegistrationOrder) {
    EditorContext context;
    context.GetSceneManager().NewScene("Overlay Provider Registry");

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = {};
    const SceneViewportOverlayBuildContext buildContext =
        CreateBuildContext(context, overlay, selectedObjectIds);

    SceneViewportOverlayProviderRegistry registry;
    registry.AddProvider(std::make_unique<MarkerOverlayProvider>(1.0f));
    registry.AddProvider(std::make_unique<MarkerOverlayProvider>(2.0f));

    ASSERT_EQ(registry.GetProviderCount(), 2u);
    ASSERT_NE(registry.GetProvider(0u), nullptr);
    ASSERT_NE(registry.GetProvider(1u), nullptr);

    SceneViewportOverlayFrameData frameData = {};
    frameData.overlay = overlay;
    registry.AppendOverlay(buildContext, frameData);

    ASSERT_EQ(frameData.worldLines.size(), 2u);
    EXPECT_FLOAT_EQ(frameData.worldLines[0].startWorld.x, 1.0f);
    EXPECT_FLOAT_EQ(frameData.worldLines[1].startWorld.x, 2.0f);
}

TEST(SceneViewportOverlayProviderRegistryTest, CameraProviderBuildsSceneIconAndSelectedFrustum) {
    EditorContext context;
    context.GetSceneManager().NewScene("Camera Overlay Provider");

    auto* cameraEntity = context.GetSceneManager().CreateEntity("SceneCamera");
    ASSERT_NE(cameraEntity, nullptr);
    cameraEntity->GetTransform()->SetPosition(Math::Vector3(0.0f, 0.0f, 5.0f));

    auto* camera = cameraEntity->AddComponent<Components::CameraComponent>();
    ASSERT_NE(camera, nullptr);
    camera->SetNearClipPlane(0.3f);
    camera->SetFarClipPlane(20.0f);

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = { cameraEntity->GetID() };
    const SceneViewportOverlayBuildContext buildContext =
        CreateBuildContext(context, overlay, selectedObjectIds);

    auto provider = CreateSceneViewportCameraOverlayProvider();
    ASSERT_NE(provider, nullptr);

    SceneViewportOverlayFrameData frameData = {};
    frameData.overlay = overlay;
    provider->AppendOverlay(buildContext, frameData);

    ASSERT_EQ(frameData.worldSprites.size(), 1u);
    EXPECT_EQ(frameData.worldSprites[0].textureKind, SceneViewportOverlaySpriteTextureKind::Camera);
    ASSERT_EQ(frameData.handleRecords.size(), 1u);
    EXPECT_EQ(frameData.handleRecords[0].entityId, cameraEntity->GetID());
    EXPECT_EQ(frameData.worldLines.size(), 12u);
}

TEST(SceneViewportOverlayProviderRegistryTest, LightProviderBuildsSceneIconAndSelectedDirectionalHelper) {
    EditorContext context;
    context.GetSceneManager().NewScene("Light Overlay Provider");

    auto* lightEntity = context.GetSceneManager().CreateEntity("DirectionalLight");
    ASSERT_NE(lightEntity, nullptr);
    lightEntity->GetTransform()->SetPosition(Math::Vector3(0.0f, 0.0f, 5.0f));

    auto* light = lightEntity->AddComponent<Components::LightComponent>();
    ASSERT_NE(light, nullptr);
    light->SetLightType(Components::LightType::Directional);

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = { lightEntity->GetID() };
    const SceneViewportOverlayBuildContext buildContext =
        CreateBuildContext(context, overlay, selectedObjectIds);

    auto provider = CreateSceneViewportLightOverlayProvider();
    ASSERT_NE(provider, nullptr);

    SceneViewportOverlayFrameData frameData = {};
    frameData.overlay = overlay;
    provider->AppendOverlay(buildContext, frameData);

    ASSERT_EQ(frameData.worldSprites.size(), 1u);
    EXPECT_EQ(frameData.worldSprites[0].textureKind, SceneViewportOverlaySpriteTextureKind::DirectionalLight);
    ASSERT_EQ(frameData.handleRecords.size(), 1u);
    EXPECT_EQ(frameData.handleRecords[0].entityId, lightEntity->GetID());
    EXPECT_GT(frameData.worldLines.size(), 0u);

    const SceneViewportOverlayLinePrimitive* connectorLine =
        FindLineStartingAt(frameData, lightEntity->GetTransform()->GetPosition());
    ASSERT_NE(connectorLine, nullptr);
    EXPECT_GT(connectorLine->endWorld.z, connectorLine->startWorld.z);
}

TEST(SceneViewportOverlayProviderRegistryTest, LightProviderBuildsSelectedPointLightHelper) {
    EditorContext context;
    context.GetSceneManager().NewScene("Point Light Overlay Provider");

    auto* lightEntity = context.GetSceneManager().CreateEntity("PointLight");
    ASSERT_NE(lightEntity, nullptr);
    lightEntity->GetTransform()->SetPosition(Math::Vector3(0.0f, 0.0f, 12.0f));

    auto* light = lightEntity->AddComponent<Components::LightComponent>();
    ASSERT_NE(light, nullptr);
    light->SetLightType(Components::LightType::Point);
    light->SetRange(3.5f);

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = { lightEntity->GetID() };
    const SceneViewportOverlayBuildContext buildContext =
        CreateBuildContext(context, overlay, selectedObjectIds);

    auto provider = CreateSceneViewportLightOverlayProvider();
    ASSERT_NE(provider, nullptr);

    SceneViewportOverlayFrameData frameData = {};
    frameData.overlay = overlay;
    provider->AppendOverlay(buildContext, frameData);

    ASSERT_EQ(frameData.worldSprites.size(), 1u);
    EXPECT_EQ(frameData.worldSprites[0].textureKind, SceneViewportOverlaySpriteTextureKind::PointLight);
    ASSERT_EQ(frameData.handleRecords.size(), 1u);
    EXPECT_EQ(frameData.handleRecords[0].entityId, lightEntity->GetID());
    EXPECT_EQ(frameData.worldLines.size(), 96u);
    EXPECT_NEAR(
        (frameData.worldLines[0].startWorld - lightEntity->GetTransform()->GetPosition()).Magnitude(),
        light->GetRange(),
        1e-3f);
}

TEST(SceneViewportOverlayProviderRegistryTest, LightProviderBuildsSelectedSpotLightHelper) {
    EditorContext context;
    context.GetSceneManager().NewScene("Spot Light Overlay Provider");

    auto* lightEntity = context.GetSceneManager().CreateEntity("SpotLight");
    ASSERT_NE(lightEntity, nullptr);
    lightEntity->GetTransform()->SetPosition(Math::Vector3(0.0f, 0.0f, 6.0f));

    auto* light = lightEntity->AddComponent<Components::LightComponent>();
    ASSERT_NE(light, nullptr);
    light->SetLightType(Components::LightType::Spot);
    light->SetRange(4.0f);
    light->SetSpotAngle(30.0f);

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = { lightEntity->GetID() };
    const SceneViewportOverlayBuildContext buildContext =
        CreateBuildContext(context, overlay, selectedObjectIds);

    auto provider = CreateSceneViewportLightOverlayProvider();
    ASSERT_NE(provider, nullptr);

    SceneViewportOverlayFrameData frameData = {};
    frameData.overlay = overlay;
    provider->AppendOverlay(buildContext, frameData);

    ASSERT_EQ(frameData.worldSprites.size(), 1u);
    EXPECT_EQ(frameData.worldSprites[0].textureKind, SceneViewportOverlaySpriteTextureKind::SpotLight);
    ASSERT_EQ(frameData.handleRecords.size(), 1u);
    EXPECT_EQ(frameData.handleRecords[0].entityId, lightEntity->GetID());
    EXPECT_EQ(frameData.worldLines.size(), 37u);

    const SceneViewportOverlayLinePrimitive* connectorLine =
        FindLineStartingAt(frameData, lightEntity->GetTransform()->GetPosition());
    ASSERT_NE(connectorLine, nullptr);
    EXPECT_GT(connectorLine->endWorld.z, connectorLine->startWorld.z);
}

TEST(SceneViewportOverlayProviderRegistryTest, TransformGizmoProviderBuildsOverlayFromFormalState) {
    EditorContext context;
    context.GetSceneManager().NewScene("Transform Gizmo Overlay Provider");

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = {};
    const SceneViewportTransformGizmoOverlayState gizmoState = CreateMoveGizmoOverlayState(73u);
    const SceneViewportOverlayBuildContext buildContext =
        CreateBuildContext(context, overlay, selectedObjectIds, 1280u, 720u, &gizmoState);

    auto provider = CreateSceneViewportTransformGizmoOverlayProvider();
    ASSERT_NE(provider, nullptr);

    SceneViewportOverlayFrameData frameData = {};
    frameData.overlay = overlay;
    provider->AppendOverlay(buildContext, frameData);

    ASSERT_EQ(frameData.handleRecords.size(), 1u);
    EXPECT_EQ(frameData.handleRecords[0].kind, SceneViewportOverlayHandleKind::MoveAxis);
    EXPECT_EQ(frameData.handleRecords[0].handleId, static_cast<uint64_t>(SceneViewportGizmoAxis::X));
    EXPECT_EQ(frameData.handleRecords[0].entityId, 73u);
    EXPECT_GT(frameData.screenTriangles.size(), 0u);
    EXPECT_TRUE(frameData.worldLines.empty());
    EXPECT_TRUE(frameData.worldSprites.empty());
}

TEST(
    SceneViewportOverlayProviderRegistryTest,
    OverlayBuilderUsesDefaultRegistryToAggregateCameraAndLightProviders) {
    EditorContext context;
    context.GetSceneManager().NewScene("Overlay Builder");

    auto* cameraEntity = context.GetSceneManager().CreateEntity("SceneCamera");
    ASSERT_NE(cameraEntity, nullptr);
    cameraEntity->GetTransform()->SetPosition(Math::Vector3(-0.5f, 0.0f, 5.0f));
    ASSERT_NE(cameraEntity->AddComponent<Components::CameraComponent>(), nullptr);

    auto* lightEntity = context.GetSceneManager().CreateEntity("DirectionalLight");
    ASSERT_NE(lightEntity, nullptr);
    lightEntity->GetTransform()->SetPosition(Math::Vector3(0.5f, 0.0f, 5.0f));
    auto* light = lightEntity->AddComponent<Components::LightComponent>();
    ASSERT_NE(light, nullptr);
    light->SetLightType(Components::LightType::Directional);

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = { cameraEntity->GetID(), lightEntity->GetID() };

    SceneViewportOverlayBuilder builder;
    const SceneViewportOverlayFrameData frameData =
        builder.Build(context, overlay, 1280u, 720u, selectedObjectIds);

    EXPECT_TRUE(frameData.overlay.valid);
    EXPECT_EQ(frameData.worldSprites.size(), 2u);
    EXPECT_EQ(frameData.handleRecords.size(), 2u);
    EXPECT_TRUE(ContainsSpriteKind(frameData, SceneViewportOverlaySpriteTextureKind::Camera));
    EXPECT_TRUE(ContainsSpriteKind(frameData, SceneViewportOverlaySpriteTextureKind::DirectionalLight));
    EXPECT_GT(frameData.worldLines.size(), 12u);
}

TEST(
    SceneViewportOverlayProviderRegistryTest,
    OverlayBuilderAppendsFormalTransformGizmoProviderOutput) {
    EditorContext context;
    context.GetSceneManager().NewScene("Overlay Builder Transform Gizmo");

    const SceneViewportOverlayData overlay = CreateValidOverlay();
    const std::vector<uint64_t> selectedObjectIds = {};
    const SceneViewportTransformGizmoOverlayState gizmoState = CreateMoveGizmoOverlayState(91u);

    SceneViewportOverlayBuilder builder;
    const SceneViewportOverlayFrameData frameData =
        builder.Build(context, overlay, 1280u, 720u, selectedObjectIds, &gizmoState);

    EXPECT_TRUE(frameData.overlay.valid);
    ASSERT_EQ(frameData.handleRecords.size(), 1u);
    EXPECT_EQ(frameData.handleRecords[0].entityId, 91u);
    EXPECT_GT(frameData.screenTriangles.size(), 0u);
}

} // namespace
} // namespace XCEngine::Editor