#include "vde/sdf/sdf_tree.h"
#include <gtest/gtest.h>
#include <cmath>

using namespace vde::sdf;
using vde::core::Point3D;
using vde::core::Vector3D;

// ── Null/empty tree ──────────────────────────────────────────────

TEST(SdfTree, NullNodeReturnsLargeValue) {
    SdfNodePtr null_node = nullptr;
    double d = evaluate(null_node, Point3D(0, 0, 0));
    EXPECT_GT(d, 1e10);
}

// ── Primitive evaluation ─────────────────────────────────────────

TEST(SdfTree, SphereInsideOutsideBoundary) {
    auto s = SdfNode::sphere(1.0);

    // Origin = inside
    double d_in = evaluate(s, Point3D(0, 0, 0));
    EXPECT_LT(d_in, 0.0);
    EXPECT_NEAR(d_in, -1.0, 1e-6);

    // Surface (r=1 on X axis)
    double d_surf = evaluate(s, Point3D(1, 0, 0));
    EXPECT_NEAR(d_surf, 0.0, 1e-6);

    // Outside
    double d_out = evaluate(s, Point3D(2, 0, 0));
    EXPECT_GT(d_out, 0.0);
    EXPECT_NEAR(d_out, 1.0, 1e-6);
}

TEST(SdfTree, BoxEvaluation) {
    auto b = SdfNode::box(Point3D(1, 1, 1));

    // Center = inside
    EXPECT_LT(evaluate(b, Point3D(0, 0, 0)), 0.0);
    // Surface
    EXPECT_NEAR(evaluate(b, Point3D(1, 0, 0)), 0.0, 1e-6);
    // Outside
    EXPECT_GT(evaluate(b, Point3D(2, 0, 0)), 0.0);
}

TEST(SdfTree, TorusEvaluation) {
    auto t = SdfNode::torus(1.0, 0.3);

    // Point on the ring centerline (should be -minor_radius = inside)
    double d = evaluate(t, Point3D(1, 0, 0));
    EXPECT_LT(d, 0.0);
    EXPECT_NEAR(d, -0.3, 1e-6);
}

TEST(SdfTree, CylinderEvaluation) {
    auto c = SdfNode::cylinder(0.5, 1.0);

    EXPECT_LT(evaluate(c, Point3D(0, 0, 0)), 0.0);     // center
    EXPECT_NEAR(evaluate(c, Point3D(0.5, 0, 0)), 0.0, 1e-6); // surface
    EXPECT_GT(evaluate(c, Point3D(1, 0, 0)), 0.0);      // outside radius
    EXPECT_GT(evaluate(c, Point3D(0, 2, 0)), 0.0);      // above cap
}

TEST(SdfTree, PlaneEvaluation) {
    auto p = SdfNode::plane(Vector3D(0, 1, 0), 0.0); // horizontal at y=0

    EXPECT_GT(evaluate(p, Point3D(0, 1, 0)), 0.0);  // above
    EXPECT_LT(evaluate(p, Point3D(0, -1, 0)), 0.0); // below
    EXPECT_NEAR(evaluate(p, Point3D(0, 0, 0)), 0.0, 1e-6);
}

// ── CSG boolean operations ───────────────────────────────────────

TEST(SdfTree, UnionSphereBox) {
    auto tree = SdfNode::op_union(
        SdfNode::sphere(1.0),
        SdfNode::box(Point3D(1, 1, 1))
    );

    // Point inside sphere
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    // Point inside box (but outside sphere) — box surface at |x|=1
    EXPECT_LT(evaluate(tree, Point3D(0.5, 0, 0)), 0.0);
    // Point outside both
    EXPECT_GT(evaluate(tree, Point3D(3, 0, 0)), 0.0);
}

TEST(SdfTree, IntersectionSphereBox) {
    auto tree = SdfNode::op_intersection(
        SdfNode::sphere(1.0),
        SdfNode::box(Point3D(0.5, 0.5, 0.5))
    );

    // Inside intersection region
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    // Inside sphere but outside box
    EXPECT_GT(evaluate(tree, Point3D(0.8, 0, 0)), 0.0);
}

TEST(SdfTree, DifferenceSphereBox) {
    auto tree = SdfNode::op_difference(
        SdfNode::sphere(2.0),
        SdfNode::box(Point3D(1, 1, 1))
    );

    // Inside sphere, outside box → inside
    EXPECT_LT(evaluate(tree, Point3D(1.5, 0, 0)), 0.0);
    // Inside box (removed region) → outside
    EXPECT_GT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
}

// ── Smooth boolean operations ────────────────────────────────────

TEST(SdfTree, SmoothUnion) {
    auto tree = SdfNode::smooth_union(
        SdfNode::sphere(1.0),
        SdfNode::sphere(1.0),
        0.3
    );

    // Both spheres at origin → should be equivalent
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
}

// ── Domain transforms ────────────────────────────────────────────

TEST(SdfTree, TranslatedSphere) {
    auto tree = SdfNode::translate(
        SdfNode::sphere(1.0),
        Point3D(2, 0, 0)
    );

    // Original origin should be far away
    EXPECT_GT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    // New center should be inside
    EXPECT_LT(evaluate(tree, Point3D(2, 0, 0)), 0.0);
    EXPECT_NEAR(evaluate(tree, Point3D(2, 0, 0)), -1.0, 1e-6);
    // Surface at new center + radius
    EXPECT_NEAR(evaluate(tree, Point3D(3, 0, 0)), 0.0, 1e-6);
}

TEST(SdfTree, ScaledSphere) {
    auto tree = SdfNode::scale(
        SdfNode::sphere(1.0),
        Point3D(2, 1, 1)
    );

    // At (2,0,0) in world = (1,0,0) in local → on surface
    EXPECT_NEAR(evaluate(tree, Point3D(2, 0, 0)), 0.0, 1e-6);
    // At (0,0,0) in world = inside
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
}

TEST(SdfTree, RepeatedSphere) {
    auto tree = SdfNode::repeat(
        SdfNode::sphere(0.3),
        Point3D(2, 2, 2)
    );

    // Origin → mapped to (0,0,0) inside
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    // (2,0,0) → mapped to (0,0,0) inside
    EXPECT_LT(evaluate(tree, Point3D(2, 0, 0)), 0.0);
    // Between copies → outside
    EXPECT_GT(evaluate(tree, Point3D(1, 1, 0)), 0.0);
}

TEST(SdfTree, MirroredX) {
    auto tree = SdfNode::mirror_x(
        SdfNode::sphere(1.0)
    );

    // Both sides should have the sphere
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    EXPECT_LT(evaluate(tree, Point3D(-0.5, 0, 0)), 0.0);
    // Surface at ±1
    EXPECT_NEAR(evaluate(tree, Point3D(1, 0, 0)), 0.0, 1e-6);
    EXPECT_NEAR(evaluate(tree, Point3D(-1, 0, 0)), 0.0, 1e-6);
}

// ── Nested operations ────────────────────────────────────────────

TEST(SdfTree, NestedUnionTwist) {
    auto inner = SdfNode::op_union(
        SdfNode::sphere(1.0),
        SdfNode::box(Point3D(0.6, 0.6, 0.6))
    );
    auto tree = SdfNode::twist(std::move(inner), 0.5);

    // Should still evaluate successfully
    double d = evaluate(tree, Point3D(0, 0.5, 0));
    EXPECT_LT(d, 0.0); // interior of union
}

TEST(SdfTree, DeepNesting) {
    auto a = SdfNode::sphere(1.0);
    auto b = SdfNode::box(Point3D(0.5, 0.5, 0.5));
    auto uni = SdfNode::op_union(std::move(a), std::move(b));
    auto scaled = SdfNode::scale(std::move(uni), Point3D(2, 2, 2));
    auto translated = SdfNode::translate(std::move(scaled), Point3D(3, 0, 0));

    // Original origin → should be inside after inverse transform + union
    double d = evaluate(translated, Point3D(3, 0, 0));
    EXPECT_LT(d, 0.0);
}

// ── Modifiers ────────────────────────────────────────────────────

TEST(SdfTree, RoundModifier) {
    auto tree = SdfNode::round(
        SdfNode::box(Point3D(1, 1, 1)),
        0.2
    );

    // Center still inside
    EXPECT_LT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    // Original corner point (1,1,0) should now be outside (rounded away)
    double d_corner = evaluate(tree, Point3D(1, 0, 0));
    // Rounded box should have slightly larger radius at corners
    // The exact value depends on implementation, just verify it's farther
    double d_box = evaluate(SdfNode::box(Point3D(1, 1, 1)), Point3D(1, 0, 0));
    EXPECT_NEAR(d_corner, d_box - 0.2, 1e-6);
}

TEST(SdfTree, OnionModifier) {
    auto tree = SdfNode::onion(
        SdfNode::sphere(2.0),
        0.3
    );

    // Center should be outside (hollowed out)
    EXPECT_GT(evaluate(tree, Point3D(0, 0, 0)), 0.0);
    // Shell surface should exist
    EXPECT_NEAR(evaluate(tree, Point3D(1.7, 0, 0)), 0.0, 1e-6);
}

// ── Bounds estimation ────────────────────────────────────────────

TEST(SdfTree, EstimateBoundsSphere) {
    auto s = SdfNode::sphere(2.0);
    Point3D b = estimate_bounds(s, 0.0);
    EXPECT_NEAR(b.x(), 2.0, 1e-6);
    EXPECT_NEAR(b.y(), 2.0, 1e-6);
    EXPECT_NEAR(b.z(), 2.0, 1e-6);
}

TEST(SdfTree, EstimateBoundsWithMargin) {
    auto s = SdfNode::sphere(2.0);
    Point3D b = estimate_bounds(s, 1.0);
    EXPECT_NEAR(b.x(), 3.0, 1e-6);
}

TEST(SdfTree, EstimateBoundsUnion) {
    auto tree = SdfNode::op_union(
        SdfNode::sphere(2.0),
        SdfNode::box(Point3D(3, 3, 3))
    );
    Point3D b = estimate_bounds(tree, 0.0);
    // Box half-extent norm = sqrt(27) ≈ 5.196
    EXPECT_GT(b.norm(), 4.0);
}

TEST(SdfTree, EstimateBoundsTranslated) {
    auto tree = SdfNode::translate(
        SdfNode::sphere(1.0),
        Point3D(5, 0, 0)
    );
    Point3D b = estimate_bounds(tree, 0.0);
    EXPECT_GT(b.norm(), 5.0);
}

// ── Tree traversal ───────────────────────────────────────────────

TEST(SdfTree, VisitCountsNodes) {
    auto tree = SdfNode::op_union(
        SdfNode::sphere(1.0),
        SdfNode::box(Point3D(1, 1, 1))
    );

    int count = 0;
    tree->visit([&count](const SdfNode&) { ++count; });
    EXPECT_EQ(count, 3); // union + sphere + box
}