/// @file fuzz_format.cpp
/// @brief 格式往返模糊测试（IGES/STEP）+ 持续运行模式
///
/// 测试策略：
///   1. 随机生成 B-Rep 体 → IGES 导出 → IGES 导入 → 验证一致性
///   2. 随机生成 B-Rep 体 → STEP 导出 → STEP 导入 → 验证一致性
///   3. 极端尺寸的格式往返
///   4. 多体格式往返
///   5. 持续运行模式

#include <gtest/gtest.h>
#include "vde/brep/brep.h"
#include "vde/brep/modeling.h"
#include "vde/brep/iges_export.h"
#include "vde/brep/iges_import.h"
#include "vde/brep/step_export.h"
#include "vde/brep/step_import.h"
#include "vde/core/point.h"
#include <cmath>
#include <random>
#include <string>
#include <cstdlib>

using namespace vde::brep;
using namespace vde::core;

static std::mt19937 s_rng(42);

namespace {

double rand_range(double lo, double hi) {
    return std::uniform_real_distribution<double>(lo, hi)(s_rng);
}

BrepModel rand_body() {
    int choice = static_cast<int>(rand_range(0, 3));
    switch (choice) {
    case 0:
        return make_box(rand_range(0.5, 10.0),
                        rand_range(0.5, 10.0),
                        rand_range(0.5, 10.0));
    case 1:
        return make_cylinder(rand_range(0.3, 5.0),
                             rand_range(0.5, 10.0),
                             static_cast<int>(rand_range(8, 32)));
    default:
        return make_sphere(rand_range(0.3, 5.0),
                           static_cast<int>(rand_range(8, 24)),
                           static_cast<int>(rand_range(4, 12)));
    }
}

} // anonymous

// ═══════════════════════════════════════════════
//  IGES 随机往返
// ═══════════════════════════════════════════════

TEST(FuzzFormat, Iges_RandomRoundTrip) {
    for (int i = 0; i < 30; ++i) {
        auto body = rand_body();
        EXPECT_TRUE(body.is_valid());

        // 导出 IGES
        std::string iges;
        EXPECT_NO_THROW({
            iges = export_iges({body});
        });
        EXPECT_FALSE(iges.empty()) << "IGES export failed at iteration " << i;

        // 重新导入
        std::vector<BrepModel> loaded;
        EXPECT_NO_THROW({
            loaded = import_iges_from_string(iges);
        });
        EXPECT_FALSE(loaded.empty()) << "IGES import failed at iteration " << i;

        // 验证导入体
        for (auto& lb : loaded) {
            EXPECT_TRUE(lb.is_valid()) << "imported body invalid at iteration " << i;
        }
    }
}

TEST(FuzzFormat, Iges_MultiBodyRoundTrip) {
    for (int i = 0; i < 15; ++i) {
        int count = static_cast<int>(rand_range(2, 5));
        std::vector<BrepModel> bodies;
        for (int j = 0; j < count; ++j) {
            bodies.push_back(rand_body());
        }

        std::string iges;
        EXPECT_NO_THROW({ iges = export_iges(bodies); });
        EXPECT_FALSE(iges.empty());

        std::vector<BrepModel> loaded;
        EXPECT_NO_THROW({ loaded = import_iges_from_string(iges); });
        EXPECT_FALSE(loaded.empty());
        EXPECT_GE(loaded.size(), 1u); // 可能合并或保留多个体

        for (auto& lb : loaded) {
            EXPECT_TRUE(lb.is_valid());
        }
    }
}

TEST(FuzzFormat, Iges_ExtremeSizes) {
    // 极端尺寸的 IGES 往返
    double sizes[] = {1e-3, 1e-1, 1.0, 10.0, 100.0, 1000.0};
    for (double s : sizes) {
        auto body = make_box(s, s * 0.5, s * 2.0);

        EXPECT_NO_THROW({
            std::string iges = export_iges({body});
            EXPECT_FALSE(iges.empty());

            auto loaded = import_iges_from_string(iges);
            EXPECT_FALSE(loaded.empty());
            EXPECT_TRUE(loaded[0].is_valid());
        }) << "failed at size=" << s;
    }
}

// ═══════════════════════════════════════════════
//  STEP 随机往返
// ═══════════════════════════════════════════════

TEST(FuzzFormat, Step_RandomRoundTrip) {
    for (int i = 0; i < 30; ++i) {
        auto body = rand_body();
        EXPECT_TRUE(body.is_valid());

        std::string step;
        EXPECT_NO_THROW({
            step = export_step({body});
        });
        EXPECT_FALSE(step.empty()) << "STEP export failed at iteration " << i;

        std::vector<BrepModel> loaded;
        EXPECT_NO_THROW({
            loaded = import_step_from_string(step);
        });
        EXPECT_FALSE(loaded.empty()) << "STEP import failed at iteration " << i;

        for (auto& lb : loaded) {
            EXPECT_TRUE(lb.is_valid()) << "imported body invalid at iteration " << i;
        }
    }
}

TEST(FuzzFormat, Step_MultiBodyRoundTrip) {
    for (int i = 0; i < 15; ++i) {
        int count = static_cast<int>(rand_range(2, 5));
        std::vector<BrepModel> bodies;
        for (int j = 0; j < count; ++j) {
            bodies.push_back(rand_body());
        }

        std::string step;
        EXPECT_NO_THROW({ step = export_step(bodies); });
        EXPECT_FALSE(step.empty());

        std::vector<BrepModel> loaded;
        EXPECT_NO_THROW({ loaded = import_step_from_string(step); });
        EXPECT_FALSE(loaded.empty());

        for (auto& lb : loaded) {
            EXPECT_TRUE(lb.is_valid());
        }
    }
}

TEST(FuzzFormat, Step_ExtremeSizes) {
    double sizes[] = {1e-3, 1e-1, 1.0, 10.0, 100.0, 1000.0};
    for (double s : sizes) {
        auto body = make_box(s, s * 0.5, s * 2.0);

        EXPECT_NO_THROW({
            std::string step = export_step({body});
            EXPECT_FALSE(step.empty());

            auto loaded = import_step_from_string(step);
            EXPECT_FALSE(loaded.empty());
            EXPECT_TRUE(loaded[0].is_valid());
        }) << "failed at size=" << s;
    }
}

// ═══════════════════════════════════════════════
//  交叉格式往返（IGES → STEP → IGES）
// ═══════════════════════════════════════════════

TEST(FuzzFormat, CrossFormat_IGES_to_STEP) {
    for (int i = 0; i < 15; ++i) {
        auto body = rand_body();

        EXPECT_NO_THROW({
            // IGES export → STEP import
            std::string iges = export_iges({body});
            auto from_iges = import_iges_from_string(iges);
            EXPECT_FALSE(from_iges.empty());

            // STEP export → IGES import
            std::string step = export_step({body});
            auto from_step = import_step_from_string(step);
            EXPECT_FALSE(from_step.empty());

            // Both should be valid
            EXPECT_TRUE(from_iges[0].is_valid());
            EXPECT_TRUE(from_step[0].is_valid());
        });
    }
}

TEST(FuzzFormat, CrossFormat_STEP_to_IGES) {
    for (int i = 0; i < 15; ++i) {
        auto body = rand_body();

        EXPECT_NO_THROW({
            // STEP → IGES
            std::string step = export_step({body});
            auto from_step = import_step_from_string(step);
            ASSERT_FALSE(from_step.empty());

            std::string iges = export_iges(from_step);
            auto from_iges = import_iges_from_string(iges);
            EXPECT_FALSE(from_iges.empty());
            EXPECT_TRUE(from_iges[0].is_valid());
        });
    }
}

// ═══════════════════════════════════════════════
//  布尔运算后的格式往返
// ═══════════════════════════════════════════════

TEST(FuzzFormat, BooleanThenRoundTrip) {
    for (int i = 0; i < 10; ++i) {
        auto a = rand_body();
        auto b = rand_body();

        EXPECT_NO_THROW({
            // 先做布尔运算
            auto u = brep_union(a, b);

            // IGES 往返
            std::string iges = export_iges({u});
            auto from_iges = import_iges_from_string(iges);
            EXPECT_FALSE(from_iges.empty());
            EXPECT_TRUE(from_iges[0].is_valid());

            // STEP 往返
            std::string step = export_step({u});
            auto from_step = import_step_from_string(step);
            EXPECT_FALSE(from_step.empty());
            EXPECT_TRUE(from_step[0].is_valid());
        });
    }
}

// ═══════════════════════════════════════════════
//  持续运行模式
// ═══════════════════════════════════════════════

TEST(FuzzFormat, ContinuousFuzz) {
    const char* forever = std::getenv("VDE_FUZZ_FOREVER");
    if (!forever || std::string(forever) != "1") {
        GTEST_SKIP() << "设置 VDE_FUZZ_FOREVER=1 启用持续模糊测试";
    }

    int iteration = 0;
    while (true) {
        ++iteration;
        auto body = rand_body();
        ASSERT_TRUE(body.is_valid());

        // IGES 往返
        std::string iges = export_iges({body});
        ASSERT_FALSE(iges.empty());
        auto from_iges = import_iges_from_string(iges);
        ASSERT_FALSE(from_iges.empty()) << "IGES import failed at iteration " << iteration;
        ASSERT_TRUE(from_iges[0].is_valid());

        // STEP 往返
        std::string step = export_step({body});
        ASSERT_FALSE(step.empty());
        auto from_step = import_step_from_string(step);
        ASSERT_FALSE(from_step.empty()) << "STEP import failed at iteration " << iteration;
        ASSERT_TRUE(from_step[0].is_valid());

        if (iteration % 1000 == 0) {
            std::cout << "[FuzzFormat] iteration=" << iteration
                      << " iges_len=" << iges.size()
                      << " step_len=" << step.size()
                      << std::endl;
        }
    }
}