#include <gtest/gtest.h>
#include "vde/brep/brep_drawing.h"
#include "vde/brep/modeling.h"
#include <cmath>
#include <fstream>
#include <cstdio>

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

// ═══════════════════════════════════════════════════════════
//  generate_views — 基本测试
// ═══════════════════════════════════════════════════════════

TEST(BrepDrawingTest, GenerateViews_Box_ReturnsFourViews) {
    auto box = make_box(2, 3, 4);
    auto views = generate_views(box);

    EXPECT_EQ(views.size(), 4u);
    EXPECT_EQ(views[0].name, "front");
    EXPECT_EQ(views[1].name, "top");
    EXPECT_EQ(views[2].name, "right");
    EXPECT_EQ(views[3].name, "iso");
}

TEST(BrepDrawingTest, GenerateViews_Box_EachViewHasSegments) {
    auto box = make_box(2, 3, 4);
    auto views = generate_views(box);

    for (const auto& v : views) {
        EXPECT_GT(v.total_segments(), 0u)
            << "View " << v.name << " should have segments";
    }
}

TEST(BrepDrawingTest, GenerateViews_Box_FrontViewHasExpectedContent) {
    auto box = make_box(2, 2, 2);
    auto views = generate_views(box);

    const auto& front = views[0];
    EXPECT_EQ(front.name, "front");
    // Front view: XY plane projection, should show X=[-1,1], Y=[-1,1]
    EXPECT_GT(front.total_segments(), 0u);
}

TEST(BrepDrawingTest, GenerateViews_Box_ViewDirections) {
    auto box = make_box(1, 1, 1);
    auto views = generate_views(box);

    // Front: looking down -Z
    EXPECT_NEAR(views[0].view_direction.z(), -1.0, 1e-6);

    // Top: looking down -Y
    EXPECT_NEAR(views[1].view_direction.y(), -1.0, 1e-6);

    // Right: looking down -X
    EXPECT_NEAR(views[2].view_direction.x(), -1.0, 1e-6);
}

TEST(BrepDrawingTest, GenerateViews_EmptyBody_ReturnsEmpty) {
    BrepModel empty;
    auto views = generate_views(empty);
    EXPECT_TRUE(views.empty());
}

TEST(BrepDrawingTest, GenerateViews_Cylinder_ReturnsFourViews) {
    auto cyl = make_cylinder(1.0, 3.0, 16);
    auto views = generate_views(cyl);

    EXPECT_EQ(views.size(), 4u);
    for (const auto& v : views) {
        EXPECT_GT(v.total_segments(), 0u);
    }
}

TEST(BrepDrawingTest, GenerateViews_Sphere_ReturnsFourViews) {
    auto sphere = make_sphere(2.0, 16, 8);
    auto views = generate_views(sphere);

    EXPECT_EQ(views.size(), 4u);
    // 球所有视图的主要轮廓应类似
    for (const auto& v : views) {
        ASSERT_GT(v.total_segments(), 0u);
    }
}

// ═══════════════════════════════════════════════════════════
//  section_view — 测试
// ═══════════════════════════════════════════════════════════

TEST(BrepDrawingTest, SectionView_Box_AtCenter) {
    auto box = make_box(4, 4, 4);
    // 截平面 z = 0（XY 平面，法向量沿 Z）
    auto view = section_view(box, Point3D(0, 0, 0), Vector3D(0, 0, 1));

    EXPECT_EQ(view.name, "section");
    // 截面应为矩形轮廓，至少有 4 个交点形成轮廓线段
    // + hatch 线，总数应 > 4
    ASSERT_GT(view.total_segments(), 4u);
}

TEST(BrepDrawingTest, SectionView_Box_HorizontalPlane) {
    auto box = make_box(4, 4, 4);
    // z = 1 的水平截面（穿过盒子）
    auto view = section_view(box, Point3D(0, 0, 1), Vector3D(0, 0, 1));

    ASSERT_GT(view.total_segments(), 4u);
}

TEST(BrepDrawingTest, SectionView_Box_PlaneOutside) {
    auto box = make_box(2, 2, 2);
    // 截平面在盒子之外（z = 5）
    auto view = section_view(box, Point3D(0, 0, 5), Vector3D(0, 0, 1));

    // 交点不足 3 个 → 无法形成截面
    EXPECT_LT(view.total_segments(), 3u);
}

TEST(BrepDrawingTest, SectionView_EmptyBody_ReturnsEmpty) {
    BrepModel empty;
    auto view = section_view(empty, Point3D(0, 0, 0), Vector3D(0, 0, 1));

    EXPECT_EQ(view.name, "section");
    EXPECT_EQ(view.total_segments(), 0u);
}

TEST(BrepDrawingTest, SectionView_Cylinder_Midplane) {
    auto cyl = make_cylinder(2.0, 6.0, 32);
    // 垂直圆柱的 z=0 截面 → 圆形截面
    auto view = section_view(cyl, Point3D(0, 0, 0), Vector3D(0, 0, 1));

    ASSERT_GT(view.segments.size(), 3u);
}

// ═══════════════════════════════════════════════════════════
//  DXF 导出 — 测试
// ═══════════════════════════════════════════════════════════

TEST(BrepDrawingTest, ExportDxf_CreatesFile) {
    auto box = make_box(2, 2, 2);
    auto views = generate_views(box);

    const char* filepath = "test_output.dxf";
    std::remove(filepath);  // 清理旧文件

    bool ok = export_dxf(filepath, views);
    EXPECT_TRUE(ok);

    // 验证文件存在
    std::ifstream in(filepath);
    EXPECT_TRUE(in.is_open());
    std::string content((std::istreambuf_iterator<char>(in)),
                         std::istreambuf_iterator<char>());
    in.close();

    // 验证关键结构
    EXPECT_NE(content.find("SECTION"), std::string::npos);
    EXPECT_NE(content.find("ENTITIES"), std::string::npos);
    EXPECT_NE(content.find("LINE"), std::string::npos);
    EXPECT_NE(content.find("ENDSEC"), std::string::npos);
    EXPECT_NE(content.find("EOF"), std::string::npos);

    // 验证有至少一条 LINE 实体
    EXPECT_NE(content.find("LINE"), std::string::npos);

    std::remove(filepath);
}

TEST(BrepDrawingTest, ExportDxf_HasLayers) {
    auto box = make_box(2, 2, 2);
    auto views = generate_views(box);

    const char* filepath = "test_layers.dxf";
    std::remove(filepath);
    export_dxf(filepath, views);

    std::ifstream in(filepath);
    std::string content((std::istreambuf_iterator<char>(in)),
                         std::istreambuf_iterator<char>());
    in.close();

    EXPECT_NE(content.find("visible"), std::string::npos);
    EXPECT_NE(content.find("DASHED"), std::string::npos);

    std::remove(filepath);
}

TEST(BrepDrawingTest, ExportDxf_EmptyViews_StillWritesSkeleton) {
    std::vector<ProjectionView> empty_views;

    const char* filepath = "test_empty.dxf";
    std::remove(filepath);
    bool ok = export_dxf(filepath, empty_views);
    EXPECT_TRUE(ok);

    std::ifstream in(filepath);
    std::string content((std::istreambuf_iterator<char>(in)),
                         std::istreambuf_iterator<char>());
    in.close();

    EXPECT_NE(content.find("SECTION"), std::string::npos);
    EXPECT_NE(content.find("EOF"), std::string::npos);

    std::remove(filepath);
}

TEST(BrepDrawingTest, ExportDxf_InvalidPath_ReturnsFalse) {
    auto box = make_box(1, 1, 1);
    auto views = generate_views(box);
    bool ok = export_dxf("/nonexistent_dir_xyz/test.dxf", views);
    EXPECT_FALSE(ok);
}

// ═══════════════════════════════════════════════════════════
//  隐藏线 — 测试
// ═══════════════════════════════════════════════════════════

TEST(BrepDrawingTest, HiddenLines_Box_HasHiddenEdges) {
    auto box = make_box(2, 2, 2);
    auto views = generate_views(box);

    // 每个标准视图均应有隐藏边
    for (size_t i = 0; i < std::min(views.size(), 3u); ++i) {
        // 前/俯/右视图都应该有隐藏线
        EXPECT_GE(views[i].hidden_lines.size() + views[i].segments.size(), 1u);
    }
}

TEST(BrepDrawingTest, DrawSegment_DefaultNotHidden) {
    DrawSegment seg{0, 0, 1, 1};
    EXPECT_FALSE(seg.hidden);
}

TEST(BrepDrawingTest, DrawSegment_Hidden) {
    DrawSegment seg{0, 0, 1, 1, true};
    EXPECT_TRUE(seg.hidden);
}

TEST(BrepDrawingTest, ProjectionView_TotalSegments) {
    ProjectionView v;
    v.segments = {{0,0,1,0}, {1,0,1,1}};
    v.hidden_lines = {{0,1,0,0, true}};
    EXPECT_EQ(v.total_segments(), 3u);
}