#include <gtest/gtest.h>
#include "vde/curves/advanced_intersection.h"
#include "vde/curves/nurbs_curve.h"
#include "vde/curves/nurbs_surface.h"
#include <cmath>

using namespace vde::curves;
using namespace vde::core;

// ---------------------------------------------------------------------------
//  Helpers
// ---------------------------------------------------------------------------

/// 平面 XY 平面 [0,1]×[0,1]
static NurbsSurface plane_surface() {
    std::vector<std::vector<Point3D>> grid = {
        {Point3D(0,0,0), Point3D(0,1,0)},
        {Point3D(1,0,0), Point3D(1,1,0)}
    };
    return NurbsSurface(grid, {0,0,1,1}, {0,0,1,1}, {{1,1},{1,1}}, 1, 1);
}

/// 倾斜平面（对角线方向）
static NurbsSurface tilted_plane() {
    std::vector<std::vector<Point3D>> grid = {
        {Point3D(0,0,0), Point3D(0,1,0.5)},
        {Point3D(1,0,0.5), Point3D(1,1,1)}
    };
    return NurbsSurface(grid, {0,0,1,1}, {0,0,1,1}, {{1,1},{1,1}}, 1, 1);
}

/// 抛物面
static NurbsSurface quad_surface() {
    std::vector<std::vector<Point3D>> grid = {
        {Point3D(0,0,0), Point3D(0,1,0.5), Point3D(0,2,0)},
        {Point3D(1,0,0.5), Point3D(1,1,1), Point3D(1,2,0.5)},
        {Point3D(2,0,0), Point3D(2,1,0.5), Point3D(2,2,0)}
    };
    return NurbsSurface(grid,
        {0,0,0,1,1,1}, {0,0,0,1,1,1},
        {{1,1,1},{1,1,1},{1,1,1}}, 2, 2);
}

/// 构造简单 NURBS 曲线
static NurbsCurve line(double x0, double y0, double z0, double x1, double y1, double z1) {
    return NurbsCurve(
        {Point3D(x0, y0, z0), Point3D(x1, y1, z1)},
        {0, 0, 1, 1}, {1, 1}, 1);
}

/// 三次 NURBS 曲线
static NurbsCurve cubic_curve() {
    return NurbsCurve(
        {Point3D(0,0,0), Point3D(1,2,0), Point3D(2,1,0), Point3D(3,0,0)},
        {0,0,0,0,1,1,1,1}, {1,1,1,1}, 3);
}

// ---------------------------------------------------------------------------
//  Test: Robust SSI — 鲁棒曲面求交
// ---------------------------------------------------------------------------

TEST(AdvancedIntersectionTest, RobustSSI_NonIntersectingPlanes) {
    auto a = plane_surface();
    // 平面在 Z=5，与 XY 平面无交
    std::vector<std::vector<Point3D>> grid2 = {
        {Point3D(0,0,5), Point3D(0,1,5)},
        {Point3D(1,0,5), Point3D(1,1,5)}
    };
    auto b = NurbsSurface(grid2, {0,0,1,1}, {0,0,1,1}, {{1,1},{1,1}}, 1, 1);

    SSIOptions opts;
    auto result = robust_ssi(a, b, opts);

    EXPECT_TRUE(result.success);
    EXPECT_EQ(0u, result.segments.size());
}

TEST(AdvancedIntersectionTest, RobustSSI_CoincidentPlanes) {
    auto a = plane_surface();
    auto b = plane_surface();  // 完全相同

    auto result = robust_ssi(a, b);

    EXPECT_TRUE(result.success);
    // 重合面应检测到交线（可能多个）
    EXPECT_GT(result.phase1_subdivisions, 0);
}

TEST(AdvancedIntersectionTest, RobustSSI_CrossingPlanes) {
    // XY 平面
    auto a = plane_surface();
    // XZ 平面（法向量为 Y 方向）
    std::vector<std::vector<Point3D>> grid2 = {
        {Point3D(0,0.5,0), Point3D(0,0.5,1)},
        {Point3D(1,0.5,0), Point3D(1,0.5,1)}
    };
    auto b = NurbsSurface(grid2, {0,0,1,1}, {0,0,1,1}, {{1,1},{1,1}}, 1, 1);

    auto result = robust_ssi(a, b);

    EXPECT_TRUE(result.success);
    // 两相交平面应有交线
    EXPECT_GT(result.segments.size(), 0u);
}

TEST(AdvancedIntersectionTest, RobustSSI_PhaseStatistics) {
    auto a = tilted_plane();
    auto b = plane_surface();

    auto result = robust_ssi(a, b);

    // 阶段统计应合理
    EXPECT_GE(result.phase1_subdivisions, 0);
    EXPECT_GE(result.phase2_converged + result.phase2_diverged,
              static_cast<int>(result.segments.size()));
    EXPECT_GE(result.total_time_ms, 0.0);
}

TEST(AdvancedIntersectionTest, RobustSSI_NewtonPrecision) {
    auto a = tilted_plane();
    auto b = plane_surface();

    SSIOptions opts;
    opts.newton_tolerance = 1e-10;
    opts.max_newton_iter = 25;

    auto result = robust_ssi(a, b, opts);

    // 检查结果精度
    for (const auto& seg : result.segments) {
        for (size_t i = 0; i < seg.points.size(); ++i) {
            auto pa = a.evaluate(seg.params_a[i].first, seg.params_a[i].second);
            auto pb = b.evaluate(seg.params_b[i].first, seg.params_b[i].second);
            EXPECT_LT((pa - pb).norm(), 1e-4);
        }
    }
}

// ---------------------------------------------------------------------------
//  Test: Curve-Surface Intersection — 曲线-曲面求交
// ---------------------------------------------------------------------------

TEST(AdvancedIntersectionTest, CurveSurfaceIntersection_LineThroughPlane) {
    auto surf = plane_surface();
    auto curve = line(0.5, 0.5, -1, 0.5, 0.5, 2);  // 垂直穿过的线

    auto pts = curve_surface_intersection(curve, surf);

    // 应检测到1个交点
    EXPECT_GE(pts.size(), 1u);
    if (!pts.empty()) {
        EXPECT_NEAR(pts[0].position.z(), 0.0, 1e-4);
    }
}

TEST(AdvancedIntersectionTest, CurveSurfaceIntersection_LineParallelToPlane) {
    auto surf = plane_surface();
    // 平行于 XY 平面的线（在 z=5 处）
    auto curve = line(0, 0, 5, 1, 1, 5);

    auto pts = curve_surface_intersection(curve, surf);

    // 平行线不应有交点（除非重合）
    for (const auto& p : pts) {
        EXPECT_NEAR(p.position.z(), 5.0, 1e-3);
    }
}

TEST(AdvancedIntersectionTest, CurveSurfaceIntersection_SortedByT) {
    auto surf = quad_surface();
    // 斜穿曲面的线（应在多处相交）
    auto curve = line(0.5, 0.5, -1, 1.5, 1.5, 2);

    auto pts = curve_surface_intersection(curve, surf);

    // 交点应按 t 排序
    for (size_t i = 1; i < pts.size(); ++i) {
        EXPECT_GE(pts[i].t, pts[i-1].t);
    }
}

TEST(AdvancedIntersectionTest, CurveSurfaceIntersection_TangentContact) {
    auto surf = plane_surface();
    // 在平面内的线
    auto curve = line(0, 0, 0, 1, 1, 0);

    auto pts = curve_surface_intersection(curve, surf);

    // 平面内的线可能有切线接触
    // （实现可能返回多个交点或标记为切线）
    for (const auto& p : pts) {
        EXPECT_NEAR(p.distance, 0.0, 1e-8);
    }
}

// ---------------------------------------------------------------------------
//  Test: Self-Intersection Detection — 自交检测
// ---------------------------------------------------------------------------

TEST(AdvancedIntersectionTest, SelfIntersection_PlaneNoSelfIntersection) {
    auto s = plane_surface();
    auto result = self_intersection_detection(s);

    // 平面不应自交
    EXPECT_FALSE(result.has_self_intersection);
    EXPECT_EQ(0u, result.regions.size());
    EXPECT_GT(result.total_checks, 0);
}

TEST(AdvancedIntersectionTest, SelfIntersection_QuadSurfaceNoSelfIntersection) {
    auto s = quad_surface();
    auto result = self_intersection_detection(s, 1e-6);

    // 规则曲面不应自交
    EXPECT_FALSE(result.has_self_intersection);
    EXPECT_GT(result.total_checks, 0);
}

TEST(AdvancedIntersectionTest, SelfIntersection_DetectionTime) {
    auto s = quad_surface();
    auto result = self_intersection_detection(s, 1e-8);

    EXPECT_GE(result.detection_time_ms, 0.0);
    EXPECT_GT(result.total_checks, 0);
}