/// @file bench_boolean_perf.cpp
/// @brief 布尔性能基准测试
///
/// 测试不同面数模型的 union / intersect / difference 性能。
/// 结果输出到 stdout，由 CI 汇总后写入 docs/benchmark-report.md

#include <gtest/gtest.h>
#include "vde/brep/brep.h"
#include "vde/brep/modeling.h"
#include "vde/brep/brep_boolean.h"
#include <chrono>
#include <iostream>
#include <iomanip>
#include <vector>
#include <string>

using namespace vde::brep;
using namespace std::chrono;

// ── 计时辅助 ──

struct BenchmarkResult {
    std::string name;
    double time_ms;
    size_t faces_a;
    size_t faces_b;
    size_t faces_result;
};

static std::vector<BenchmarkResult> g_results;

static double measure_ms(std::function<void()> fn, int iterations = 3) {
    double best = 1e18;
    for (int i = 0; i < iterations; ++i) {
        auto start = high_resolution_clock::now();
        fn();
        auto end = high_resolution_clock::now();
        double ms = duration_cast<microseconds>(end - start).count() / 1000.0;
        if (ms < best) best = ms;
    }
    return best;
}

static void record(const std::string& name, double ms,
                   size_t fa, size_t fb, size_t fr) {
    g_results.push_back({name, ms, fa, fb, fr});
    std::cout << "  [BENCH] " << std::left << std::setw(40) << name
              << std::right << std::setw(10) << std::fixed << std::setprecision(2)
              << ms << " ms"
              << "  (faces: " << fa << " + " << fb << " → " << fr << ")"
              << std::endl;
}

// ═══════════════════════════════════════════════
//  布尔并集基准
// ═══════════════════════════════════════════════

TEST(BenchmarkBoolean, Union_SmallModels) {
    // 小面数：两个低分辨率球体
    auto a = make_sphere(1.0, 8, 4);
    auto b = make_sphere(0.8, 8, 4);

    double ms = measure_ms([&]() {
        auto u = brep_union(a, b);
        (void)u.num_faces();
    }, 5);

    auto result = brep_union(a, b);
    record("Boolean.Union/Small", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

TEST(BenchmarkBoolean, Union_MediumModels) {
    // 中面数：两个中等细分球体
    auto a = make_sphere(2.0, 16, 8);
    auto b = make_sphere(1.5, 16, 8);

    double ms = measure_ms([&]() {
        auto u = brep_union(a, b);
        (void)u.num_faces();
    }, 3);

    auto result = brep_union(a, b);
    record("Boolean.Union/Medium", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

TEST(BenchmarkBoolean, Union_LargeModels) {
    // 大面数：两个高细分球体
    auto a = make_sphere(3.0, 24, 16);
    auto b = make_sphere(2.5, 24, 16);

    double ms = measure_ms([&]() {
        auto u = brep_union(a, b);
        (void)u.num_faces();
    }, 3);

    auto result = brep_union(a, b);
    record("Boolean.Union/Large", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

// ═══════════════════════════════════════════════
//  布尔交集基准
// ═══════════════════════════════════════════════

TEST(BenchmarkBoolean, Intersection_Small) {
    auto a = make_sphere(1.0, 8, 4);
    auto b = make_box(1.2, 1.2, 1.2);

    double ms = measure_ms([&]() {
        auto i = brep_intersection(a, b);
        (void)i.num_faces();
    }, 5);

    auto result = brep_intersection(a, b);
    record("Boolean.Intersection/Small", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

TEST(BenchmarkBoolean, Intersection_Medium) {
    auto a = make_sphere(2.0, 16, 8);
    auto b = make_cylinder(1.5, 4.0, 32);

    double ms = measure_ms([&]() {
        auto i = brep_intersection(a, b);
        (void)i.num_faces();
    }, 3);

    auto result = brep_intersection(a, b);
    record("Boolean.Intersection/Medium", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

TEST(BenchmarkBoolean, Intersection_Large) {
    auto a = make_sphere(3.0, 24, 16);
    auto b = make_cylinder(2.0, 6.0, 64);

    double ms = measure_ms([&]() {
        auto i = brep_intersection(a, b);
        (void)i.num_faces();
    }, 3);

    auto result = brep_intersection(a, b);
    record("Boolean.Intersection/Large", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

// ═══════════════════════════════════════════════
//  布尔差集基准
// ═══════════════════════════════════════════════

TEST(BenchmarkBoolean, Difference_Small) {
    auto a = make_box(2.0, 2.0, 2.0);
    auto b = make_sphere(0.8, 8, 4);

    double ms = measure_ms([&]() {
        auto d = brep_difference(a, b);
        (void)d.num_faces();
    }, 5);

    auto result = brep_difference(a, b);
    record("Boolean.Difference/Small", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

TEST(BenchmarkBoolean, Difference_Medium) {
    auto a = make_box(4.0, 4.0, 4.0);
    auto b = make_sphere(1.5, 16, 8);

    double ms = measure_ms([&]() {
        auto d = brep_difference(a, b);
        (void)d.num_faces();
    }, 3);

    auto result = brep_difference(a, b);
    record("Boolean.Difference/Medium", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}

TEST(BenchmarkBoolean, Difference_Large) {
    auto a = make_box(6.0, 6.0, 6.0);
    auto b = make_sphere(2.0, 24, 16);

    double ms = measure_ms([&]() {
        auto d = brep_difference(a, b);
        (void)d.num_faces();
    }, 3);

    auto result = brep_difference(a, b);
    record("Boolean.Difference/Large", ms, a.num_faces(), b.num_faces(), result.num_faces());
    EXPECT_TRUE(result.is_valid());
}