#include <gtest/gtest.h>
#include "vde/curves/generative_surfaces.h"
#include "vde/curves/nurbs_curve.h"
#include "vde/core/point.h"
#include <cmath>

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

// ── 辅助：创建直线 NURBS ──
static NurbsCurve make_line(const Point3D& a, const Point3D& b) {
    return NurbsCurve({a, b}, {0, 0, 1, 1}, {1, 1}, 1);
}

// ── 辅助：创建圆弧 profile ──
static NurbsCurve make_arc_profile() {
    double r = 1.0;
    double w = std::sqrt(2.0) / 2.0;
    return NurbsCurve(
        {Point3D(0, r, 0), Point3D(r, r, 0), Point3D(r, 0, 0)},
        {0, 0, 0, 0.5, 1, 1, 1},
        {1, w, 1, w, 1, w, 1},
        2
    );
}

// ============================================================================
//  Sweep 测试
// ============================================================================

TEST(GenerativeSurfacesTest, SweepExplicit_Basic) {
    // 圆形 profile 沿直线扫描 → 圆柱面
    NurbsCurve profile(
        {Point3D(0, 1, 0), Point3D(1, 1, 0), Point3D(1, 0, 0)},
        {0, 0, 0, 1, 1, 1},
        {1, 1, 1},
        2
    );
    NurbsCurve path = make_line({0, 0, 0}, {0, 0, 5});

    SweepOption opt;
    opt.type = SweepType::Explicit;
    opt.samples = 8;

    auto surf = sweep_surface(profile, path, opt);

    EXPECT_EQ(surf.degree_u(), 2);
    EXPECT_GE(surf.num_control_points()[0], 3);
    EXPECT_GE(surf.num_control_points()[1], 3);

    // 验证曲面在参数域中点可求值
    auto p = surf.evaluate(0.5, 0.5);
    EXPECT_GE(p.x(), 0.0);
    EXPECT_LE(p.z(), 5.0);
}

TEST(GenerativeSurfacesTest, SweepExplicit_StraightPath) {
    // 矩形 profile 沿 X 轴扫描
    NurbsCurve profile = make_line({0, 0, 0}, {0, 0, 2});
    NurbsCurve path = make_line({0, 0, 0}, {10, 0, 0});

    SweepOption opt;
    opt.type = SweepType::Explicit;
    opt.samples = 4;

    auto surf = sweep_surface(profile, path, opt);

    // 验证曲面两端
    auto p0 = surf.evaluate(0.0, 0.0);
    auto p1 = surf.evaluate(1.0, 1.0);

    EXPECT_NEAR(p0.x(), 0.0, 1e-6);
    EXPECT_NEAR(p1.x(), 10.0, 1e-6);
    EXPECT_GE(p1.z(), 0.0);
}

TEST(GenerativeSurfacesTest, SweepExplicit_VaryingSamples) {
    NurbsCurve profile = make_line({0, 1, 0}, {0, -1, 0});
    NurbsCurve path = make_line({0, 0, 0}, {0, 0, 3});

    SweepOption opt;
    opt.type = SweepType::Explicit;
    opt.samples = 16;

    auto surf = sweep_surface(profile, path, opt);

    // 控制点数量应随采样增加
    int n_u = surf.num_control_points()[0];
    EXPECT_GT(n_u, 4);

    // 曲面可正常求值
    auto mid = surf.evaluate(0.5, 0.5);
    EXPECT_NEAR(mid.x(), 0.0, 1e-6);
    EXPECT_NEAR(mid.z(), 1.5, 1.0);
}

TEST(GenerativeSurfacesTest, SweepSpine_Basic) {
    // 使用独立脊线的扫描
    NurbsCurve profile = make_line({0, 1, 0}, {0, -1, 0});
    NurbsCurve path = make_line({0, 0, 0}, {5, 0, 0});

    // 脊线偏离路径，用于扭转控制
    NurbsCurve spine = make_line({0, 0, 0}, {5, 0, 2});

    SweepOption opt;
    opt.type = SweepType::Spine;
    opt.spine = spine;
    opt.samples = 8;

    auto surf = sweep_surface(profile, path, opt);

    EXPECT_GE(surf.num_control_points()[0], 3);
    EXPECT_GE(surf.num_control_points()[1], 2);

    // 验证曲面可求值
    auto p = surf.evaluate(0.5, 0.5);
    EXPECT_FALSE(std::isnan(p.x()));
    EXPECT_FALSE(std::isnan(p.y()));
    EXPECT_FALSE(std::isnan(p.z()));
}

TEST(GenerativeSurfacesTest, SweepTwoGuides_Basic) {
    // 双引导线扫描：两条引导线间距变化控制缩放
    NurbsCurve profile = make_line({0, 1, 0}, {0, -1, 0});
    NurbsCurve path = make_line({0, 0, 0}, {5, 0, 0});

    // 两条引导线逐渐分开
    NurbsCurve guide1 = make_line({0, 0.5, 0}, {5, 2, 0});
    NurbsCurve guide2 = make_line({0, -0.5, 0}, {5, -2, 0});

    SweepOption opt;
    opt.type = SweepType::TwoGuides;
    opt.guide1 = guide1;
    opt.guide2 = guide2;
    opt.samples = 8;

    auto surf = sweep_surface(profile, path, opt);

    EXPECT_GE(surf.num_control_points()[0], 3);
    EXPECT_GE(surf.num_control_points()[1], 2);

    // 曲面起点和终点宽度应不同（缩放生效）
    auto p_start = surf.evaluate(0.0, 0.5);
    auto p_end = surf.evaluate(1.0, 0.5);
    EXPECT_GE(std::abs(p_end.y()) - std::abs(p_start.y()), -0.5);
}

TEST(GenerativeSurfacesTest, Sweep_DefaultOption) {
    // 默认选项（Explicit 模式）
    NurbsCurve profile = make_line({0, 1, 0}, {0, -1, 0});
    NurbsCurve path = make_line({0, 0, 0}, {3, 0, 0});

    auto surf = sweep_surface(profile, path);

    EXPECT_GE(surf.num_control_points()[0], 3);
    auto p = surf.evaluate(0.5, 0.5);
    EXPECT_FALSE(std::isnan(p.x()));
}

// ============================================================================
//  Loft 测试
// ============================================================================

TEST(GenerativeSurfacesTest, Loft_Basic) {
    // 两条平行截面放样
    NurbsCurve s1 = make_line({0, 0, 0}, {2, 0, 0});
    NurbsCurve s2 = make_line({0, 2, 5}, {2, 2, 5});

    auto surf = loft_surface({s1, s2});

    EXPECT_GE(surf.num_control_points()[0], 2);
    EXPECT_GE(surf.num_control_points()[1], 2);

    // 验证曲面插值首尾截面
    auto p_bottom = surf.evaluate(0.5, 0.0);
    EXPECT_NEAR(p_bottom.z(), 0.0, 1e-6);

    auto p_top = surf.evaluate(0.5, 1.0);
    EXPECT_NEAR(p_top.z(), 5.0, 1e-6);
}

TEST(GenerativeSurfacesTest, Loft_ThreeSections) {
    NurbsCurve s1 = make_line({0, 0, 0}, {2, 0, 0});
    NurbsCurve s2 = make_line({0, 1, 3}, {2, 1, 3});
    NurbsCurve s3 = make_line({0, 0, 6}, {2, 0, 6});

    auto surf = loft_surface({s1, s2, s3});

    EXPECT_GE(surf.num_control_points()[0], 2);
    EXPECT_GE(surf.num_control_points()[1], 2);

    // 中间截面应偏离直线
    auto p_mid = surf.evaluate(0.5, 0.5);
    EXPECT_NEAR(p_mid.z(), 3.0, 1.0);
    EXPECT_GT(p_mid.y(), 0.0);
}

TEST(GenerativeSurfacesTest, Loft_WithGuides) {
    NurbsCurve s1 = make_line({0, 0, 0}, {2, 0, 0});
    NurbsCurve s2 = make_line({0, 0, 5}, {2, 0, 5});
    NurbsCurve s3 = make_line({0, 0, 10}, {2, 0, 10});

    // 引导线：弯曲的脊线
    NurbsCurve guide(
        {Point3D(0, 1, 2.5), Point3D(1, 0, 5), Point3D(0, -1, 7.5)},
        {0, 0, 0, 1, 1, 1},
        {1, 1, 1},
        2
    );

    auto surf = loft_surface({s1, s2, s3}, {guide});

    EXPECT_GE(surf.num_control_points()[0], 2);
    EXPECT_GE(surf.num_control_points()[1], 2);

    auto p = surf.evaluate(0.5, 0.5);
    EXPECT_FALSE(std::isnan(p.x()));
}

TEST(GenerativeSurfacesTest, Loft_WithTangents) {
    NurbsCurve s1 = make_line({0, 0, 0}, {2, 0, 0});
    NurbsCurve s2 = make_line({0, 0, 5}, {2, 0, 5});

    LoftConstraint cons;
    cons.start_tangent = Vector3D(0, 0, 1);  // 垂直向上
    cons.end_tangent = Vector3D(0, 0, 1);    // 垂直向上

    auto surf = loft_surface({s1, s2}, {}, cons);

    EXPECT_GE(surf.num_control_points()[0], 2);
    EXPECT_GE(surf.num_control_points()[1], 2);

    // 曲面应能正常求值
    auto p = surf.evaluate(0.5, 0.3);
    EXPECT_FALSE(std::isnan(p.x()));
}

TEST(GenerativeSurfacesTest, Loft_InvalidInput) {
    // 单个截面应抛出异常
    NurbsCurve s1 = make_line({0, 0, 0}, {1, 0, 0});
    EXPECT_THROW((void)loft_surface({s1}), std::invalid_argument);
}

// ============================================================================
//  Net 测试
// ============================================================================

TEST(GenerativeSurfacesTest, Net_Basic) {
    // 双向曲线网格：u 向和 v 向各 2 条线
    NurbsCurve u0 = make_line({0, 0, 0}, {5, 0, 0});
    NurbsCurve u1 = make_line({0, 2, 0}, {5, 2, 0});
    NurbsCurve v0 = make_line({0, 0, 0}, {0, 2, 0});
    NurbsCurve v1 = make_line({5, 0, 0}, {5, 2, 0});

    auto surf = net_surface({u0, u1}, {v0, v1});

    EXPECT_GE(surf.num_control_points()[0], 2);
    EXPECT_GE(surf.num_control_points()[1], 2);

    // 曲面应在 XY 平面内
    auto p = surf.evaluate(0.5, 0.5);
    EXPECT_NEAR(p.z(), 0.0, 1e-6);
    EXPECT_GE(p.x(), 0.0);
    EXPECT_GE(p.y(), 0.0);
}

TEST(GenerativeSurfacesTest, Net_UnequalCount) {
    // u 向 3 条，v 向 2 条
    NurbsCurve u0 = make_line({0, 0, 0}, {5, 0, 0});
    NurbsCurve u1 = make_line({0, 1, 0}, {5, 1, 0});
    NurbsCurve u2 = make_line({0, 2, 0}, {5, 2, 0});
    NurbsCurve v0 = make_line({0, 0, 0}, {0, 2, 0});
    NurbsCurve v1 = make_line({5, 0, 0}, {5, 2, 0});

    auto surf = net_surface({u0, u1, u2}, {v0, v1});

    EXPECT_EQ(surf.num_control_points()[0], 3);
    EXPECT_EQ(surf.num_control_points()[1], 2);
}

TEST(GenerativeSurfacesTest, Net_3DCurves) {
    // 三维网格曲面
    NurbsCurve u0(
        {Point3D(0, 0, 0), Point3D(1, 0, 1), Point3D(2, 0, 0)},
        {0, 0, 0, 1, 1, 1},
        {1, 1, 1},
        2
    );
    NurbsCurve u1(
        {Point3D(0, 2, 0), Point3D(1, 2, 1), Point3D(2, 2, 0)},
        {0, 0, 0, 1, 1, 1},
        {1, 1, 1},
        2
    );
    NurbsCurve v0 = make_line({0, 0, 0}, {0, 2, 0});
    NurbsCurve v1 = make_line({2, 0, 0}, {2, 2, 0});

    auto surf = net_surface({u0, u1}, {v0, v1});

    EXPECT_GE(surf.num_control_points()[0], 2);
    EXPECT_GE(surf.num_control_points()[1], 2);

    auto p = surf.evaluate(0.5, 0.5);
    EXPECT_FALSE(std::isnan(p.x()));
    EXPECT_GE(p.z(), 0.0);
}

TEST(GenerativeSurfacesTest, Net_InvalidInput) {
    NurbsCurve u0 = make_line({0, 0, 0}, {1, 0, 0});
    EXPECT_THROW((void)net_surface({u0}, {u0}), std::invalid_argument);

    NurbsCurve v0 = make_line({0, 0, 0}, {1, 0, 0});
    EXPECT_THROW((void)net_surface({u0, u0}, {v0}), std::invalid_argument);
}

// ============================================================================
//  集成测试：组合使用
// ============================================================================

TEST(GenerativeSurfacesTest, Integration_SweepThenEvaluate) {
    // 验证扫掠后曲面求值一致性
    NurbsCurve profile = make_line({0, 1, 0}, {0, -1, 0});
    NurbsCurve path = make_line({0, 0, 0}, {10, 0, 0});

    SweepOption opt;
    opt.type = SweepType::Explicit;
    opt.samples = 10;

    auto surf = sweep_surface(profile, path, opt);

    // 曲面法向应在 XY 平面内（近似）
    for (double u = 0.0; u <= 1.0; u += 0.25) {
        for (double v = 0.0; v <= 1.0; v += 0.25) {
            auto pt = surf.evaluate(u, v);
            EXPECT_FALSE(std::isnan(pt.x()));
            EXPECT_FALSE(std::isnan(pt.y()));
            EXPECT_FALSE(std::isnan(pt.z()));
        }
    }
}