#include <gtest/gtest.h>

#include <XCEngine/Rendering/Picking/ObjectIdCodec.h>
#include <XCEngine/Rendering/Picking/RenderObjectIdRegistry.h>

using namespace XCEngine::Rendering;

TEST(ObjectIdEncoding_Test, RegistryMapsRuntimeObjectIdsToStableRenderObjectIds) {
    RenderObjectIdRegistry& registry = RenderObjectIdRegistry::Get();
    registry.Reset();

    constexpr uint64_t runtimeObjectId = 0x1ABCDEF0123ull;
    const RenderObjectId renderObjectId =
        registry.GetOrAllocateRenderObjectId(runtimeObjectId);

    ASSERT_TRUE(IsValidRenderObjectId(renderObjectId));
    EXPECT_EQ(
        registry.GetOrAllocateRenderObjectId(runtimeObjectId),
        renderObjectId);

    RenderObjectId resolvedRenderObjectId = kInvalidRenderObjectId;
    EXPECT_TRUE(
        registry.TryGetRenderObjectId(
            runtimeObjectId,
            resolvedRenderObjectId));
    EXPECT_EQ(resolvedRenderObjectId, renderObjectId);

    uint64_t resolvedRuntimeObjectId = 0u;
    EXPECT_TRUE(
        registry.TryResolveRuntimeObjectId(
            renderObjectId,
            resolvedRuntimeObjectId));
    EXPECT_EQ(resolvedRuntimeObjectId, runtimeObjectId);
    EXPECT_EQ(
        registry.ResolveRuntimeObjectId(renderObjectId),
        runtimeObjectId);
}

TEST(ObjectIdEncoding_Test, RegistryRejectsInvalidRuntimeAndRenderObjectIds) {
    RenderObjectIdRegistry& registry = RenderObjectIdRegistry::Get();
    registry.Reset();

    EXPECT_EQ(
        registry.GetOrAllocateRenderObjectId(0u),
        kInvalidRenderObjectId);

    RenderObjectId renderObjectId = 123u;
    EXPECT_FALSE(
        registry.TryGetRenderObjectId(
            0u,
            renderObjectId));
    EXPECT_EQ(renderObjectId, kInvalidRenderObjectId);

    uint64_t runtimeObjectId = 99u;
    EXPECT_FALSE(
        registry.TryResolveRuntimeObjectId(
            kInvalidRenderObjectId,
            runtimeObjectId));
    EXPECT_EQ(runtimeObjectId, 0u);
    EXPECT_EQ(
        registry.ResolveRuntimeObjectId(kInvalidRenderObjectId),
        0u);
}

TEST(ObjectIdEncoding_Test, DecodesColorBackToRenderObjectId) {
    constexpr uint8_t r = 0x12u;
    constexpr uint8_t g = 0x34u;
    constexpr uint8_t b = 0x56u;
    constexpr uint8_t a = 0x78u;

    EXPECT_EQ(DecodeEncodedObjectIdFromColor(r, g, b, a), 0x78563412u);
    EXPECT_EQ(DecodeRenderObjectIdFromColor(r, g, b, a), 0x78563412u);
}

TEST(ObjectIdEncoding_Test, EncodesColorChannelsFromRenderObjectId) {
    const auto encodedColor = EncodeRenderObjectIdToColor(0x78563412u);
    constexpr float kInv255 = 1.0f / 255.0f;

    EXPECT_FLOAT_EQ(encodedColor.x, 0x12u * kInv255);
    EXPECT_FLOAT_EQ(encodedColor.y, 0x34u * kInv255);
    EXPECT_FLOAT_EQ(encodedColor.z, 0x56u * kInv255);
    EXPECT_FLOAT_EQ(encodedColor.w, 0x78u * kInv255);
}