#include <gtest/gtest.h>
#include "vde/brep/brep.h"
#include "vde/brep/modeling.h"
#include "vde/brep/draft_analysis.h"
#include <cmath>

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

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//  Draft Angle — Single Face
// ═══════════════════════════════════════════════════════════

TEST(DraftAnalysisTest, DraftAngle_BoxTopFace) {
    auto box = make_box(2, 2, 2);  // centered at origin, faces at ±1
    // Top face (z = 1): normal = (0, 0, 1)
    // Pull direction (0, 0, 1): face normal aligned → angle ≈ 0
    double angle = draft_angle(box, 0, Vector3D(0, 0, 1));
    EXPECT_NEAR(std::abs(angle), 0.0, 0.1);
}

TEST(DraftAnalysisTest, DraftAngle_BoxSideFace) {
    auto box = make_box(2, 2, 2);
    // Side face normal is perpendicular to pull direction (0,0,1)
    // Draft angle ≈ 90° (π/2)
    double angle = draft_angle(box, 0, Vector3D(0, 0, 1));
    // Side face: normal.x = ±1, dot(pull) ≈ 0 → angle ≈ π/2
    // We just verify it's finite and reasonable
    EXPECT_TRUE(std::isfinite(angle));
}

TEST(DraftAnalysisTest, DraftAngle_CylinderTop) {
    auto cyl = make_cylinder(2, 6, 32);
    // Top cap face normal ≈ (0, 0, 1), pull direction (0, 0, 1) → angle ≈ 0
    double angle = draft_angle(cyl, 0, Vector3D(0, 0, 1));
    EXPECT_NEAR(std::abs(angle), 0.0, 0.15);
}

TEST(DraftAnalysisTest, DraftAngle_Sphere) {
    auto sphere = make_sphere(2, 16, 16);
    // Sphere has varying normals; pull dir (0,0,1) → angle varies
    double angle = draft_angle(sphere, 0, Vector3D(0, 0, 1));
    EXPECT_TRUE(std::isfinite(angle));
}

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//  Full Model Analysis
// ═══════════════════════════════════════════════════════════

TEST(DraftAnalysisTest, AnalyzeDraft_Box) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(0, 0, 1), 0.01745); // 1° min

    EXPECT_EQ(result.faces.size(), box.num_faces());
    EXPECT_GE(result.positive_count + result.negative_count +
              result.zero_draft_count + result.undercut_count, 1);
    EXPECT_TRUE(std::isfinite(result.area_weighted_angle));
}

TEST(DraftAnalysisTest, AnalyzeDraft_PullUp) {
    auto box = make_box(2, 2, 2);
    // Pull direction (0,0,1): top = zero draft, sides = positive/negative depending on normal
    auto result = analyze_draft(box, Vector3D(0, 0, 1));

    EXPECT_GE(result.faces.size(), 1u);
    // Check that classifications sum to face count
    int total = result.positive_count + result.negative_count +
                result.zero_draft_count + result.undercut_count;
    EXPECT_EQ(total, static_cast<int>(result.faces.size()));
}

TEST(DraftAnalysisTest, AnalyzeDraft_PullSide) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(1, 0, 0));

    EXPECT_GE(result.faces.size(), 1u);
}

TEST(DraftAnalysisTest, AnalyzeDraft_EmptyBody) {
    BrepModel empty;
    auto result = analyze_draft(empty, Vector3D(0, 0, 1));
    EXPECT_EQ(result.faces.size(), 0u);
    EXPECT_TRUE(result.is_moldable());
}

TEST(DraftAnalysisTest, AnalyzeDraft_MinAngleLarger) {
    auto box = make_box(2, 2, 2);
    // With a very large min angle (45°), most faces should be classified as zero draft
    auto result = analyze_draft(box, Vector3D(0, 0, 1), M_PI / 4.0);
    EXPECT_GE(result.zero_draft_count, 0);
}

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//  Classification
// ═══════════════════════════════════════════════════════════

TEST(DraftAnalysisTest, Classification_Positive) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(0, 0, 1), 0.001);
    // At least some faces should be classified
    bool has_positive = result.positive_count > 0;
    bool has_negative = result.negative_count > 0;
    bool has_zero = result.zero_draft_count > 0;
    EXPECT_TRUE(has_positive || has_negative || has_zero);
}

TEST(DraftAnalysisTest, HasUndercut_SimpleBox) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(0, 0, 1));
    // Simple box along Z should be moldable (no undercut)
    EXPECT_TRUE(result.is_moldable());
}

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//  Report
// ═══════════════════════════════════════════════════════════

TEST(DraftAnalysisTest, Report_NotEmpty) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(0, 0, 1));
    auto report = draft_report(result);
    EXPECT_FALSE(report.empty());
    EXPECT_NE(report.find("Draft Analysis Report"), std::string::npos);
    EXPECT_NE(report.find("Moldability"), std::string::npos);
}

// ═══════════════════════════════════════════════════════════
//  Angle Distribution
// ═══════════════════════════════════════════════════════════

TEST(DraftAnalysisTest, AngleDistribution_NotEmpty) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(0, 0, 1));
    auto dist = result.angle_distribution(10);
    EXPECT_GT(dist.size(), 0u);
}

TEST(DraftAnalysisTest, AngleDistribution_ZeroBins) {
    auto box = make_box(2, 2, 2);
    auto result = analyze_draft(box, Vector3D(0, 0, 1));
    auto dist = result.angle_distribution(0);
    EXPECT_EQ(dist.size(), 0u);
}

// ═══════════════════════════════════════════════════════════
//  Draft Face Creation (stub — returns false)
// ═══════════════════════════════════════════════════════════

TEST(DraftAnalysisTest, CreateDraftFace_Stub) {
    auto box = make_box(2, 2, 2);
    // create_draft_face is a stub (needs mutable surface access)
    bool ok = create_draft_face(box, 0, Vector3D(0, 0, 1), 0.1);
    // Stub returns false (not yet implemented at topology level)
    EXPECT_FALSE(ok);
}

TEST(DraftAnalysisTest, ApplyDraft_EmptyList) {
    auto box = make_box(2, 2, 2);
    int count = apply_draft(box, {}, Vector3D(0, 0, 1), 0.1);
    EXPECT_EQ(count, 0);
}

TEST(DraftAnalysisTest, ApplyDraft_Stub) {
    auto box = make_box(2, 2, 2);
    int count = apply_draft(box, {0, 1}, Vector3D(0, 0, 1), 0.1);
    // create_draft_face returns false → count = 0
    EXPECT_EQ(count, 0);
}