#include <gtest/gtest.h>
#include <XCEngine/Math/Ray.h>
#include <XCEngine/Math/Sphere.h>
#include <XCEngine/Math/Box.h>
#include <XCEngine/Math/Plane.h>
#include <XCEngine/Math/Bounds.h>
#include <XCEngine/Math/Frustum.h>
#include <XCEngine/Math/Matrix4.h>

using namespace XCEngine::Math;

namespace {

// ============================================================
// Ray Tests
// ============================================================

TEST(Math_Ray, DefaultConstructor) {
    Ray ray;
    EXPECT_FLOAT_EQ(ray.origin.x, 0.0f);
    EXPECT_FLOAT_EQ(ray.origin.y, 0.0f);
    EXPECT_FLOAT_EQ(ray.origin.z, 0.0f);
    EXPECT_FLOAT_EQ(ray.direction.x, 0.0f);
    EXPECT_FLOAT_EQ(ray.direction.y, 0.0f);
    EXPECT_FLOAT_EQ(ray.direction.z, 0.0f);
}

TEST(Math_Ray, ParameterConstructor) {
    Vector3 origin(1, 2, 3);
    Vector3 direction(0, 0, 1);
    Ray ray(origin, direction);
    
    EXPECT_FLOAT_EQ(ray.origin.x, 1.0f);
    EXPECT_FLOAT_EQ(ray.origin.y, 2.0f);
    EXPECT_FLOAT_EQ(ray.origin.z, 3.0f);
}

TEST(Math_Ray, GetPoint) {
    Ray ray(Vector3::Zero(), Vector3::Right());
    Vector3 point = ray.GetPoint(5.0f);
    
    EXPECT_FLOAT_EQ(point.x, 5.0f);
    EXPECT_FLOAT_EQ(point.y, 0.0f);
    EXPECT_FLOAT_EQ(point.z, 0.0f);
}

TEST(Math_Ray, IntersectsSphere_Hit) {
    Ray ray(Vector3(-5, 0, 0), Vector3::Right());
    Sphere sphere(Vector3::Zero(), 1.0f);
    
    float t;
    bool hit = ray.Intersects(sphere, t);
    
    EXPECT_TRUE(hit);
    EXPECT_GE(t, 0.0f);
}

TEST(Math_Ray, IntersectsSphere_Miss) {
    Ray ray(Vector3(0, 5, 0), Vector3::Right());
    Sphere sphere(Vector3::Zero(), 1.0f);
    
    float t;
    bool hit = ray.Intersects(sphere, t);
    
    EXPECT_FALSE(hit);
}

TEST(Math_Ray, IntersectsBox_Hit) {
    Ray ray(Vector3(-5, 0, 0), Vector3::Right());
    Box box(Vector3::Zero(), Vector3(1, 1, 1));
    
    float t;
    bool hit = ray.Intersects(box, t);
    
    EXPECT_TRUE(hit);
    EXPECT_GE(t, 0.0f);
}

TEST(Math_Ray, IntersectsBox_Miss) {
    Ray ray(Vector3(0, 5, 0), Vector3::Right());
    Box box(Vector3(10, 0, 0), Vector3(1, 1, 1));
    
    float t;
    bool hit = ray.Intersects(box, t);
    
    EXPECT_FALSE(hit);
}

TEST(Math_Ray, IntersectsPlane_Hit) {
    Ray ray(Vector3(0, 0, -5), Vector3::Forward());
    Plane plane(Vector3::Forward(), 0.0f);
    
    float t;
    bool hit = ray.Intersects(plane, t);
    
    EXPECT_TRUE(hit);
    EXPECT_NEAR(t, 5.0f, 1e-3f);
}

TEST(Math_Ray, IntersectsPlane_Miss) {
    Ray ray(Vector3(0, 0, -5), Vector3::Back());
    Plane plane(Vector3::Forward(), 0.0f);
    
    float t;
    bool hit = ray.Intersects(plane, t);
    
    EXPECT_FALSE(hit);
}

// ============================================================
// Sphere Tests
// ============================================================

TEST(Math_Sphere, DefaultConstructor) {
    Sphere sphere;
    EXPECT_FLOAT_EQ(sphere.center.x, 0.0f);
    EXPECT_FLOAT_EQ(sphere.radius, 0.0f);
}

TEST(Math_Sphere, ParameterConstructor) {
    Sphere sphere(Vector3(1, 2, 3), 5.0f);
    
    EXPECT_FLOAT_EQ(sphere.center.x, 1.0f);
    EXPECT_FLOAT_EQ(sphere.center.y, 2.0f);
    EXPECT_FLOAT_EQ(sphere.center.z, 3.0f);
    EXPECT_FLOAT_EQ(sphere.radius, 5.0f);
}

TEST(Math_Sphere, Contains_Inside) {
    Sphere sphere(Vector3::Zero(), 2.0f);
    EXPECT_TRUE(sphere.Contains(Vector3(1, 0, 0)));
}

TEST(Math_Sphere, Contains_Outside) {
    Sphere sphere(Vector3::Zero(), 1.0f);
    EXPECT_FALSE(sphere.Contains(Vector3(5, 0, 0)));
}

TEST(Math_Sphere, Contains_OnSurface) {
    Sphere sphere(Vector3::Zero(), 1.0f);
    EXPECT_TRUE(sphere.Contains(Vector3(1, 0, 0)));
}

TEST(Math_Sphere, Intersects_Overlap) {
    Sphere a(Vector3::Zero(), 1.0f);
    Sphere b(Vector3(1.5f, 0, 0), 1.0f);
    
    EXPECT_TRUE(a.Intersects(b));
}

TEST(Math_Sphere, Intersects_Separate) {
    Sphere a(Vector3::Zero(), 1.0f);
    Sphere b(Vector3(5, 0, 0), 1.0f);
    
    EXPECT_FALSE(a.Intersects(b));
}

// ============================================================
// Plane Tests
// ============================================================

TEST(Math_Plane, DefaultConstructor) {
    Plane plane;
    EXPECT_FLOAT_EQ(plane.normal.x, 0.0f);
    EXPECT_FLOAT_EQ(plane.normal.y, 1.0f);
    EXPECT_FLOAT_EQ(plane.normal.z, 0.0f);
    EXPECT_FLOAT_EQ(plane.distance, 0.0f);
}

TEST(Math_Plane, ParameterConstructor) {
    Plane plane(Vector3::Forward(), 5.0f);
    
    EXPECT_FLOAT_EQ(plane.normal.z, 1.0f);
    EXPECT_FLOAT_EQ(plane.distance, 5.0f);
}

TEST(Math_Plane, FromPoints) {
    Plane plane = Plane::FromPoints(
        Vector3(0, 0, 0),
        Vector3(1, 0, 0),
        Vector3(0, 1, 0)
    );
    
    EXPECT_FLOAT_EQ(plane.normal.z, -1.0f);
    EXPECT_FLOAT_EQ(plane.distance, 0.0f);
}

TEST(Math_Plane, GetDistanceToPoint) {
    Plane plane(Vector3::Forward(), 0.0f);
    float dist = plane.GetDistanceToPoint(Vector3(0, 0, 5));
    
    EXPECT_FLOAT_EQ(dist, 5.0f);
}

TEST(Math_Plane, GetClosestPoint) {
    Plane plane(Vector3::Forward(), 0.0f);
    Vector3 point = plane.GetClosestPoint(Vector3(3, 4, 5));
    
    EXPECT_FLOAT_EQ(point.x, 3.0f);
    EXPECT_FLOAT_EQ(point.y, 4.0f);
    EXPECT_FLOAT_EQ(point.z, 0.0f);
}

TEST(Math_Plane, GetSide_Positive) {
    Plane plane(Vector3::Forward(), 0.0f);
    EXPECT_TRUE(plane.GetSide(Vector3(0, 0, 1)));
}

TEST(Math_Plane, GetSide_Negative) {
    Plane plane(Vector3::Forward(), 0.0f);
    EXPECT_FALSE(plane.GetSide(Vector3(0, 0, -1)));
}

TEST(Math_Plane, IntersectsSphere_Inside) {
    Plane plane(Vector3::Forward(), 0.0f);
    Sphere sphere(Vector3(0, 0, 0), 1.0f);
    
    EXPECT_TRUE(plane.Intersects(sphere));
}

TEST(Math_Plane, IntersectsSphere_Outside) {
    Plane plane(Vector3::Forward(), 5.0f);
    Sphere sphere(Vector3(0, 0, 0), 1.0f);
    
    EXPECT_FALSE(plane.Intersects(sphere));
}

// ============================================================
// Bounds Tests
// ============================================================

TEST(Math_Bounds, DefaultConstructor) {
    Bounds bounds;
    EXPECT_FLOAT_EQ(bounds.center.x, 0.0f);
    EXPECT_FLOAT_EQ(bounds.extents.x, 0.0f);
}

TEST(Math_Bounds, ParameterConstructor) {
    Bounds bounds(Vector3(5, 5, 5), Vector3(10, 10, 10));
    
    EXPECT_FLOAT_EQ(bounds.center.x, 5.0f);
    EXPECT_FLOAT_EQ(bounds.extents.x, 5.0f);
}

TEST(Math_Bounds, GetMin) {
    Bounds bounds(Vector3(5, 5, 5), Vector3(10, 10, 10));
    Vector3 min = bounds.GetMin();
    
    EXPECT_FLOAT_EQ(min.x, 0.0f);
    EXPECT_FLOAT_EQ(min.y, 0.0f);
    EXPECT_FLOAT_EQ(min.z, 0.0f);
}

TEST(Math_Bounds, GetMax) {
    Bounds bounds(Vector3(5, 5, 5), Vector3(10, 10, 10));
    Vector3 max = bounds.GetMax();
    
    EXPECT_FLOAT_EQ(max.x, 10.0f);
    EXPECT_FLOAT_EQ(max.y, 10.0f);
    EXPECT_FLOAT_EQ(max.z, 10.0f);
}

TEST(Math_Bounds, SetMinMax) {
    Bounds bounds;
    bounds.SetMinMax(Vector3(0, 0, 0), Vector3(10, 10, 10));
    
    EXPECT_FLOAT_EQ(bounds.center.x, 5.0f);
    EXPECT_FLOAT_EQ(bounds.extents.x, 5.0f);
}

TEST(Math_Bounds, Contains_Inside) {
    Bounds bounds(Vector3::Zero(), Vector3(10, 10, 10));
    EXPECT_TRUE(bounds.Contains(Vector3::Zero()));
}

TEST(Math_Bounds, Contains_Outside) {
    Bounds bounds(Vector3::Zero(), Vector3(2, 2, 2));
    EXPECT_FALSE(bounds.Contains(Vector3(5, 5, 5)));
}

TEST(Math_Bounds, Contains_OnSurface) {
    Bounds bounds(Vector3::Zero(), Vector3(2, 2, 2));
    EXPECT_TRUE(bounds.Contains(Vector3(1, 1, 1)));
}

TEST(Math_Bounds, Intersects_Overlap) {
    Bounds a(Vector3::Zero(), Vector3(2, 2, 2));
    Bounds b(Vector3(1, 1, 1), Vector3(2, 2, 2));
    
    EXPECT_TRUE(a.Intersects(b));
}

TEST(Math_Bounds, Intersects_Separate) {
    Bounds a(Vector3::Zero(), Vector3(2, 2, 2));
    Bounds b(Vector3(10, 10, 10), Vector3(2, 2, 2));
    
    EXPECT_FALSE(a.Intersects(b));
}

TEST(Math_Bounds, Encapsulate_Point) {
    Bounds bounds(Vector3::Zero(), Vector3(2, 2, 2));
    bounds.Encapsulate(Vector3(5, 5, 5));
    
    EXPECT_GT(bounds.GetMax().x, 5.0f);
}

TEST(Math_Bounds, Encapsulate_Bounds) {
    Bounds a(Vector3::Zero(), Vector3(2, 2, 2));
    Bounds b(Vector3(5, 5, 5), Vector3(2, 2, 2));
    a.Encapsulate(b);
    
    EXPECT_GT(a.GetMax().x, 5.0f);
}

TEST(Math_Bounds, Expand) {
    Bounds bounds(Vector3::Zero(), Vector3(2, 2, 2));
    bounds.Expand(2.0f);
    
    EXPECT_GT(bounds.GetMax().x, 3.0f);
}

TEST(Math_Bounds, GetVolume) {
    Bounds bounds(Vector3::Zero(), Vector3(2, 4, 6));
    float volume = bounds.GetVolume();
    
    EXPECT_FLOAT_EQ(volume, 48.0f);
}

TEST(Math_Bounds, GetClosestPoint) {
    Bounds bounds(Vector3::Zero(), Vector3(2, 2, 2));
    Vector3 point = bounds.GetClosestPoint(Vector3(10, 10, 10));
    
    EXPECT_FLOAT_EQ(point.x, 1.0f);
    EXPECT_FLOAT_EQ(point.y, 1.0f);
    EXPECT_FLOAT_EQ(point.z, 1.0f);
}

// ============================================================
// Frustum Tests
// ============================================================

TEST(Math_Frustum, Contains_Point) {
    Frustum frustum;
    Plane nearPlane;
    nearPlane.normal = Vector3::Forward();
    nearPlane.distance = 1.0f;
    frustum.planes[4] = nearPlane;
    
    EXPECT_TRUE(frustum.Contains(Vector3(0, 0, 2)));
}

TEST(Math_Frustum, Contains_Sphere) {
    Frustum frustum;
    Plane nearPlane;
    nearPlane.normal = Vector3::Forward();
    nearPlane.distance = 1.0f;
    frustum.planes[4] = nearPlane;
    
    Sphere sphere(Vector3(0, 0, 5), 1.0f);
    EXPECT_TRUE(frustum.Contains(sphere));
}

TEST(Math_Frustum, Intersects_Sphere) {
    Frustum frustum;
    Plane nearPlane;
    nearPlane.normal = Vector3::Forward();
    nearPlane.distance = 1.0f;
    frustum.planes[4] = nearPlane;
    
    Sphere sphere(Vector3(0, 0, 2), 0.5f);
    EXPECT_TRUE(frustum.Intersects(sphere));
}

TEST(Math_Frustum, Intersects_Bounds) {
    Frustum frustum;
    Plane nearPlane;
    nearPlane.normal = Vector3::Forward();
    nearPlane.distance = 1.0f;
    frustum.planes[4] = nearPlane;
    
    Bounds bounds(Vector3(0, 0, 2), Vector3(1, 1, 1));
    EXPECT_TRUE(frustum.Intersects(bounds));
}

} // namespace