#include <gtest/gtest.h>
#include "vde/brep/brep.h"
#include "vde/brep/modeling.h"
#include "vde/brep/step_export.h"
#include <fstream>
#include <sstream>
#include <algorithm>

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

// ═══════════════════════════════════════════════════════════
//  STEP export basic tests
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, ExportBox_ProducesValidStructure) {
    auto box = make_box(2, 3, 4);
    std::string step = export_step({box});

    // Must start with ISO-10303-21 header
    EXPECT_TRUE(step.find("ISO-10303-21;") != std::string::npos);

    // Must contain HEADER section
    EXPECT_TRUE(step.find("HEADER;") != std::string::npos);
    EXPECT_TRUE(step.find("ENDSEC;") != std::string::npos);

    // Must contain DATA section
    EXPECT_TRUE(step.find("DATA;") != std::string::npos);

    // Must contain CARTESIAN_POINT entities
    EXPECT_TRUE(step.find("CARTESIAN_POINT") != std::string::npos);

    // Must contain topology entities
    EXPECT_TRUE(step.find("CLOSED_SHELL") != std::string::npos ||
                step.find("ADVANCED_FACE") != std::string::npos);

    // Must end properly
    EXPECT_TRUE(step.find("END-ISO-10303-21;") != std::string::npos);
}

TEST(StepExportTest, ExportBox_ContainsManifoldSolidBrep) {
    auto box = make_box(1, 1, 1);
    std::string step = export_step({box});

    EXPECT_TRUE(step.find("MANIFOLD_SOLID_BREP") != std::string::npos);
}

TEST(StepExportTest, ExportBox_ContainsPlanes) {
    auto box = make_box(2, 2, 2);
    std::string step = export_step({box});

    // Box faces are degree 1×1 → should export as PLANE
    EXPECT_TRUE(step.find("PLANE") != std::string::npos ||
                step.find("B_SPLINE_SURFACE") != std::string::npos);
}

TEST(StepExportTest, ExportBox_ContainsEdgeCurve) {
    auto box = make_box(1, 1, 1);
    std::string step = export_step({box});

    EXPECT_TRUE(step.find("EDGE_CURVE") != std::string::npos);
}

TEST(StepExportTest, ExportBox_ContainsOrientedEdge) {
    auto box = make_box(1, 1, 1);
    std::string step = export_step({box});

    EXPECT_TRUE(step.find("ORIENTED_EDGE") != std::string::npos);
}

TEST(StepExportTest, ExportBox_HasProperEntityNumbering) {
    auto box = make_box(1, 1, 1);
    std::string step = export_step({box});

    // Should have at least entity #1
    EXPECT_TRUE(step.find("#1 =") != std::string::npos);

    // Count entity occurrences to ensure numbering is sequential
    int entity_count = 0;
    size_t pos = 0;
    while ((pos = step.find("= ", pos)) != std::string::npos) {
        entity_count++;
        pos += 2;
    }
    EXPECT_GT(entity_count, 5);
}

// ═══════════════════════════════════════════════════════════
//  Sphere STEP export
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, ExportSphere_ProducesValidOutput) {
    auto sphere = make_sphere(2.0);
    std::string step = export_step({sphere});

    EXPECT_TRUE(step.find("ISO-10303-21;") != std::string::npos);
    EXPECT_TRUE(step.find("CARTESIAN_POINT") != std::string::npos);
    EXPECT_TRUE(step.find("MANIFOLD_SOLID_BREP") != std::string::npos ||
                step.find("CLOSED_SHELL") != std::string::npos);
}

// ═══════════════════════════════════════════════════════════
//  Cylinder STEP export
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, ExportCylinder_ProducesValidOutput) {
    auto cyl = make_cylinder(1.0, 4.0);
    std::string step = export_step({cyl});

    EXPECT_TRUE(step.find("ISO-10303-21;") != std::string::npos);
    EXPECT_TRUE(step.find("CARTESIAN_POINT") != std::string::npos);
}

// ═══════════════════════════════════════════════════════════
//  Multiple bodies
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, ExportMultipleBodies_ProducesValidOutput) {
    auto box1 = make_box(1, 1, 1);
    auto box2 = make_box(2, 2, 2);
    std::string step = export_step({box1, box2});

    EXPECT_TRUE(step.find("ISO-10303-21;") != std::string::npos);
    EXPECT_TRUE(step.find("MANIFOLD_SOLID_BREP") != std::string::npos);
}

// ═══════════════════════════════════════════════════════════
//  File export
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, ExportFile_WritesToDisk) {
    auto box = make_box(1, 1, 1);
    std::string path = "/tmp/test_vde_export.stp";
    export_step_file(path, {box});

    std::ifstream in(path);
    EXPECT_TRUE(in.good());
    std::string content((std::istreambuf_iterator<char>(in)),
                         std::istreambuf_iterator<char>());
    EXPECT_TRUE(content.find("ISO-10303-21;") != std::string::npos);
}

// ═══════════════════════════════════════════════════════════
//  Empty model
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, ExportEmptyModel_ProducesMinimalOutput) {
    BrepModel empty;
    std::string step = export_step({empty});

    EXPECT_TRUE(step.find("ISO-10303-21;") != std::string::npos);
    EXPECT_TRUE(step.find("DATA;") != std::string::npos);
}

// ═══════════════════════════════════════════════════════════
//  AP214 schema check
// ═══════════════════════════════════════════════════════════

TEST(StepExportTest, UsesAP214Schema) {
    auto box = make_box(1, 1, 1);
    std::string step = export_step({box});

    EXPECT_TRUE(step.find("AUTOMOTIVE_DESIGN") != std::string::npos ||
                step.find("AP214") != std::string::npos ||
                step.find("10303 214") != std::string::npos);
}