/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */

#include <AzCore/UnitTest/TestTypes.h>
#include <AzCore/Math/Transform.h>
#include <AzFramework/Viewport/CameraState.h>
#include <AZTestShared/Math/MathTestHelpers.h>
#include <AzCore/Math/SimdMath.h>
#include <AzCore/Math/MatrixUtils.h>
#include <AzCore/Math/Matrix4x4.h>

namespace UnitTest
{
    class CameraStateFixture
        : public ::testing::Test
    {
    public:
        void SetUp() override
        {
            m_cameraState = AzFramework::CreateDefaultCamera(AZ::Transform::CreateIdentity(), AZ::Vector2(1024, 768));
        }

        AzFramework::CameraState m_cameraState;
    };

    class Translation
        : public CameraStateFixture
        , public ::testing::WithParamInterface<AZStd::tuple<float, float, float>>
    {
    };

    class Rotation
        : public CameraStateFixture
        , public ::testing::WithParamInterface<AZStd::tuple<float, float, float>>
    {
    };

    class WorldFromViewMatrix
        : public CameraStateFixture
        , public ::testing::WithParamInterface<AZStd::tuple<AZ::Vector3, AZ::Vector3, AZ::Vector2>>
    {
    };

    class PerspectiveMatrix
        : public CameraStateFixture
        , public ::testing::WithParamInterface<AZStd::tuple<float, float, float, float>>
    {
    };

    TEST_P(Translation, Permutation)
    {
        // Given a position
        const auto [x, y, z] = GetParam();
        const AZ::Vector3 expectedPosition(x, y, z);

        // Set the camera state's transform to the expected position
        AzFramework::SetCameraTransform(m_cameraState, AZ::Transform::CreateTranslation(expectedPosition));

        // Expect the camera state transform's position to be expected position
        EXPECT_THAT(m_cameraState.m_position, IsCloseTolerance(expectedPosition, 0.01f));

        // Expect the camera state transform's orientation to be identity
        EXPECT_THAT(m_cameraState.m_forward, IsCloseTolerance(AZ::Vector3::CreateAxisY(), 0.01f));
        EXPECT_THAT(m_cameraState.m_up, IsCloseTolerance(AZ::Vector3::CreateAxisZ(), 0.01f));
        EXPECT_THAT(m_cameraState.m_side, IsCloseTolerance(AZ::Vector3::CreateAxisX(), 0.01f));
    }

    INSTANTIATE_TEST_CASE_P(
        CameraState,
        Translation,
        testing::Combine(
            testing::Values(0.0f, 1.0f),
            testing::Values(0.0f, 1.0f),
            testing::Values(0.0f, 1.0f))
    );

    TEST_P(Rotation, Permutation)
    {
        int expectedErrors = -1;
        AZ_TEST_START_TRACE_SUPPRESSION;

        // Given an orientation derived from the look at points
        const auto [x, y, z] = GetParam();
        const AZ::Vector3 from = AZ::Vector3::CreateZero();
        const AZ::Vector3 to = AZ::Vector3(x, y, z);
        const AZ::Transform expectedTransform = AZ::Transform::CreateLookAt(from, AZ::Vector3(x, y, z));

        // Set the camera's rotation to the expected orientation
        AzFramework::SetCameraTransform(m_cameraState, expectedTransform);

        // Expect the camera state transform's position to be identity
        EXPECT_THAT(m_cameraState.m_position, IsCloseTolerance(AZ::Vector3::CreateZero(), 0.01f));

        if (from.IsClose(to, 0.001f))
        {
            // Expect one error to be generated by AZ::Transform::CreateLookAt() due to from and to being the same position
            expectedErrors = 1;

            // If the look at points yield an invalid orientation, expect identity rotation basis vectors 
            EXPECT_THAT(m_cameraState.m_forward, IsCloseTolerance(AZ::Vector3::CreateAxisY(), 0.01f));
            EXPECT_THAT(m_cameraState.m_up, IsCloseTolerance(AZ::Vector3::CreateAxisZ(), 0.01f));
            EXPECT_THAT(m_cameraState.m_side, IsCloseTolerance(AZ::Vector3::CreateAxisX(), 0.01f));
        }
        else
        {
            // Expect no errors to be generated by AZ::Transform::CreateLookAt()
            expectedErrors = 0;

            // If the look at points yield a valid orientation, expect the rotation basis vectors to be that of the orientation
            EXPECT_THAT(m_cameraState.m_forward, IsCloseTolerance(expectedTransform.GetBasisY(), 0.01f));
            EXPECT_THAT(m_cameraState.m_up, IsCloseTolerance(expectedTransform.GetBasisZ(), 0.01f));
            EXPECT_THAT(m_cameraState.m_side, IsCloseTolerance(expectedTransform.GetBasisX(), 0.01f));
        }

        AZ_TEST_STOP_TRACE_SUPPRESSION(expectedErrors);
    }

    INSTANTIATE_TEST_CASE_P(
        CameraState,
        Rotation,
        testing::Combine(
            testing::Values(0.0f, 1.0f),
            testing::Values(0.0f, 1.0f),
            testing::Values(0.0f, 1.0f))
    );

    TEST_P(WorldFromViewMatrix, Permutation)
    {
        auto [translation, eulerRotation, viewportSize] = GetParam();
        // Quaternion::CreateFromEulerAnglesDegrees takes a non-const Vector3&
        AZ::Vector3 eulerRotationCopy = eulerRotation;
        AZ::Quaternion rotation = AZ::Quaternion::CreateFromEulerAnglesDegrees(eulerRotationCopy);
        AZ::Matrix4x4 worldFromView = AZ::Matrix4x4::CreateFromQuaternionAndTranslation(rotation, translation);

        m_cameraState = AzFramework::CreateCameraFromWorldFromViewMatrix(worldFromView, viewportSize);

        EXPECT_EQ(m_cameraState.m_viewportSize, viewportSize);
        EXPECT_THAT(m_cameraState.m_position, IsCloseTolerance(translation, 0.01f));
        // Translate back into a quaternion to safely compare rotations
        auto decomposedCameraStateRotation = AZ::Quaternion::CreateFromBasis(m_cameraState.m_side, m_cameraState.m_forward, m_cameraState.m_up);
        auto rotationDelta = 1.f - decomposedCameraStateRotation.Dot(decomposedCameraStateRotation);
        EXPECT_NEAR(rotationDelta, 0.f, 0.01f);
    }

    INSTANTIATE_TEST_CASE_P(
        CameraState,
        WorldFromViewMatrix,
        testing::Combine(
            testing::Values(AZ::Vector3{0.f, 0.f, 0.f}, AZ::Vector3{100.f, 0.f, 0.f}, AZ::Vector3{-5.f,10.f,-1.f}),
            testing::Values(AZ::Vector3{0.f, 0.f, 0.f}, AZ::Vector3{90.f, 0.f, 0.f}, AZ::Vector3{-45.f, -45.f, -45.f}),
            testing::Values(AZ::Vector2{100.f, 100.f})
        )
    );

    TEST_P(PerspectiveMatrix, Permutation)
    {
        auto [fovY, aspectRatio, nearClip, farClip] = GetParam();

        AZ::Matrix4x4 clipFromView;
        MakePerspectiveFovMatrixRH(clipFromView, fovY, aspectRatio, nearClip, farClip);

        AzFramework::SetCameraClippingVolumeFromPerspectiveFovMatrixRH(m_cameraState, clipFromView);

        EXPECT_NEAR(m_cameraState.m_nearClip, nearClip, 0.01f);
        EXPECT_NEAR(m_cameraState.m_farClip, farClip, 1.f);
        EXPECT_NEAR(m_cameraState.m_fovOrZoom, fovY, 0.01f);
    }

    INSTANTIATE_TEST_CASE_P(
        CameraState,
        PerspectiveMatrix,
        testing::Combine(
            testing::Values(1.f, 0.5f, 2.f),
            testing::Values(1.f, 16.f / 9.f),
            testing::Values(1.f, 50.f),
            testing::Values(100.f, 10000.f)
        )
    );

} // namespace UnitTest