/**
 * Property-Based Tests for LOD System
 * Feature: pywrkgame-library, Property 10: LOD Optimization
 * Validates: Requirements 3.7
 * 
 * Property 10: LOD Optimization
 * For any 3D scene with LOD models, appropriate detail levels should be selected 
 * based on camera distance
 */

#include <gtest/gtest.h>
#include <rapidcheck/gtest.h>
#include "pywrkgame/rendering/RenderingEngine.h"
#include "pywrkgame/rendering/LODSystem.h"
#include <cmath>
#include <algorithm>

using namespace pywrkgame::rendering;

class LODSystemTest : public ::testing::Test {
protected:
    void SetUp() override {
        renderer = std::make_unique<RenderingEngine>();
        ASSERT_TRUE(renderer->Initialize());
        ASSERT_TRUE(renderer->SetupLODSystem());
        lodSystem = renderer->GetLODSystem();
        ASSERT_NE(lodSystem, nullptr);
    }
    
    void TearDown() override {
        renderer->Shutdown();
    }
    
    std::unique_ptr<RenderingEngine> renderer;
    LODSystem* lodSystem = nullptr;
};

// Unit test: LOD system initialization
TEST_F(LODSystemTest, LODSystemInitialized) {
    EXPECT_TRUE(lodSystem->IsInitialized());
    EXPECT_TRUE(lodSystem->IsEnabled());
}

// Unit test: Create LOD group
TEST_F(LODSystemTest, CreateLODGroup) {
    uint32_t groupId = lodSystem->CreateLODGroup();
    EXPECT_NE(groupId, 0u);
    
    auto* group = lodSystem->GetLODGroup(groupId);
    ASSERT_NE(group, nullptr);
    EXPECT_EQ(group->GetLODLevelCount(), 0u);
    
    lodSystem->DestroyLODGroup(groupId);
}

// Unit test: Add LOD levels
TEST_F(LODSystemTest, AddLODLevels) {
    uint32_t groupId = lodSystem->CreateLODGroup();
    ASSERT_NE(groupId, 0u);
    
    auto* group = lodSystem->GetLODGroup(groupId);
    ASSERT_NE(group, nullptr);
    
    // Create a dummy mesh
    MeshData meshData;
    meshData.vertices = {0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f};
    meshData.indices = {0, 1, 2};
    meshData.vertexCount = 3;
    meshData.indexCount = 3;
    
    auto mesh = renderer->CreateMesh(meshData);
    ASSERT_TRUE(mesh.IsValid());
    
    // Add LOD levels
    LODLevel level0;
    level0.mesh = mesh;
    level0.distance = 10.0f;
    level0.screenCoverage = 0.5f;
    level0.triangleCount = 1000;
    
    group->AddLODLevel(level0);
    EXPECT_EQ(group->GetLODLevelCount(), 1u);
    
    LODLevel level1;
    level1.mesh = mesh;
    level1.distance = 50.0f;
    level1.screenCoverage = 0.2f;
    level1.triangleCount = 500;
    
    group->AddLODLevel(level1);
    EXPECT_EQ(group->GetLODLevelCount(), 2u);
    
    renderer->DestroyMesh(mesh);
    lodSystem->DestroyLODGroup(groupId);
}

// Unit test: LOD selection by distance
TEST_F(LODSystemTest, LODSelectionByDistance) {
    uint32_t groupId = lodSystem->CreateLODGroup();
    ASSERT_NE(groupId, 0u);
    
    auto* group = lodSystem->GetLODGroup(groupId);
    ASSERT_NE(group, nullptr);
    
    // Create dummy meshes
    MeshData meshData;
    meshData.vertices = {0.0f, 0.0f, 0.0f};
    meshData.indices = {0};
    meshData.vertexCount = 1;
    meshData.indexCount = 1;
    
    auto mesh0 = renderer->CreateMesh(meshData);
    auto mesh1 = renderer->CreateMesh(meshData);
    
    // Add LOD levels
    LODLevel level0;
    level0.mesh = mesh0;
    level0.distance = 10.0f;
    level0.triangleCount = 1000;
    
    LODLevel level1;
    level1.mesh = mesh1;
    level1.distance = 50.0f;
    level1.triangleCount = 500;
    
    group->AddLODLevel(level0);
    group->AddLODLevel(level1);
    
    // Test LOD selection
    auto selectedMesh0 = group->GetLODForDistance(5.0f);
    EXPECT_EQ(selectedMesh0, mesh0);
    
    auto selectedMesh1 = group->GetLODForDistance(30.0f);
    EXPECT_EQ(selectedMesh1, mesh1);
    
    auto selectedMesh2 = group->GetLODForDistance(100.0f);
    EXPECT_EQ(selectedMesh2, mesh1);
    
    renderer->DestroyMesh(mesh0);
    renderer->DestroyMesh(mesh1);
    lodSystem->DestroyLODGroup(groupId);
}

// Unit test: LOD bias
TEST_F(LODSystemTest, LODBias) {
    float defaultBias = lodSystem->GetLODBias();
    EXPECT_FLOAT_EQ(defaultBias, 1.0f);
    
    lodSystem->SetLODBias(2.0f);
    EXPECT_FLOAT_EQ(lodSystem->GetLODBias(), 2.0f);
    
    lodSystem->SetLODBias(0.5f);
    EXPECT_FLOAT_EQ(lodSystem->GetLODBias(), 0.5f);
}

// Unit test: Camera settings
TEST_F(LODSystemTest, CameraSettings) {
    float x, y, z;
    lodSystem->GetCameraPosition(x, y, z);
    EXPECT_FLOAT_EQ(x, 0.0f);
    EXPECT_FLOAT_EQ(y, 0.0f);
    EXPECT_FLOAT_EQ(z, 0.0f);
    
    lodSystem->SetCameraPosition(10.0f, 20.0f, 30.0f);
    lodSystem->GetCameraPosition(x, y, z);
    EXPECT_FLOAT_EQ(x, 10.0f);
    EXPECT_FLOAT_EQ(y, 20.0f);
    EXPECT_FLOAT_EQ(z, 30.0f);
    
    EXPECT_FLOAT_EQ(lodSystem->GetCameraFOV(), 60.0f);
    lodSystem->SetCameraFOV(90.0f);
    EXPECT_FLOAT_EQ(lodSystem->GetCameraFOV(), 90.0f);
}

// Unit test: Enable/disable LOD system
TEST_F(LODSystemTest, EnableDisableLODSystem) {
    EXPECT_TRUE(lodSystem->IsEnabled());
    
    lodSystem->SetEnabled(false);
    EXPECT_FALSE(lodSystem->IsEnabled());
    
    lodSystem->SetEnabled(true);
    EXPECT_TRUE(lodSystem->IsEnabled());
}

// Property Test: LOD Group Creation
RC_GTEST_PROP(LODSystemPropertyTest, LODGroupCreationIsValid, ()) {
    /*
     * Feature: pywrkgame-library, Property 10: LOD Optimization
     * For any 3D scene with LOD models, appropriate detail levels should be selected 
     * based on camera distance
     * 
     * This test verifies that:
     * 1. LOD groups can be created successfully
     * 2. Each group has a unique ID
     * 3. Groups can be retrieved by ID
     */
    
    auto renderer = std::make_unique<RenderingEngine>();
    RC_ASSERT(renderer->Initialize());
    RC_ASSERT(renderer->SetupLODSystem());
    
    auto* lodSystem = renderer->GetLODSystem();
    RC_ASSERT(lodSystem != nullptr);
    RC_ASSERT(lodSystem->IsInitialized());
    
    // Generate random number of groups (1-10)
    auto numGroups = *rc::gen::inRange(1, 11);
    
    std::vector<uint32_t> groupIds;
    
    // Create groups
    for (int i = 0; i < numGroups; ++i) {
        uint32_t id = lodSystem->CreateLODGroup();
        RC_ASSERT(id != 0);
        
        // Verify ID is unique
        for (auto existingId : groupIds) {
            RC_ASSERT(id != existingId);
        }
        
        groupIds.push_back(id);
    }
    
    // Verify all groups can be retrieved
    for (auto id : groupIds) {
        auto* group = lodSystem->GetLODGroup(id);
        RC_ASSERT(group != nullptr);
    }
    
    // Clean up
    for (auto id : groupIds) {
        lodSystem->DestroyLODGroup(id);
    }
    
    renderer->Shutdown();
}

// Property Test: LOD Selection Based on Distance
RC_GTEST_PROP(LODSystemPropertyTest, LODSelectionIsCorrect, ()) {
    /*
     * Feature: pywrkgame-library, Property 10: LOD Optimization
     * 
     * This test verifies that:
     * 1. LOD selection is based on distance thresholds
     * 2. Closer distances select higher quality LODs
     * 3. Farther distances select lower quality LODs
     */
    
    auto renderer = std::make_unique<RenderingEngine>();
    RC_ASSERT(renderer->Initialize());
    RC_ASSERT(renderer->SetupLODSystem());
    
    auto* lodSystem = renderer->GetLODSystem();
    RC_ASSERT(lodSystem != nullptr);
    
    uint32_t groupId = lodSystem->CreateLODGroup();
    RC_ASSERT(groupId != 0);
    
    auto* group = lodSystem->GetLODGroup(groupId);
    RC_ASSERT(group != nullptr);
    
    // Create dummy meshes
    MeshData meshData;
    meshData.vertices = {0.0f};
    meshData.indices = {0};
    meshData.vertexCount = 1;
    meshData.indexCount = 1;
    
    auto mesh0 = renderer->CreateMesh(meshData);
    auto mesh1 = renderer->CreateMesh(meshData);
    
    RC_ASSERT(mesh0.IsValid());
    RC_ASSERT(mesh1.IsValid());
    
    // Generate random distance thresholds
    auto distance0 = *rc::gen::inRange(1.0f, 50.0f);
    auto distance1 = *rc::gen::inRange(distance0 + 1.0f, 100.0f);
    
    // Add LOD levels
    LODLevel level0;
    level0.mesh = mesh0;
    level0.distance = distance0;
    level0.triangleCount = 1000;
    
    LODLevel level1;
    level1.mesh = mesh1;
    level1.distance = distance1;
    level1.triangleCount = 500;
    
    group->AddLODLevel(level0);
    group->AddLODLevel(level1);
    
    // Test: distance less than first threshold should select LOD 0
    auto testDistance0 = distance0 * 0.5f;
    auto selectedMesh0 = group->GetLODForDistance(testDistance0);
    RC_ASSERT(selectedMesh0 == mesh0);
    
    // Test: distance between thresholds should select LOD 1
    auto testDistance1 = (distance0 + distance1) * 0.5f;
    auto selectedMesh1 = group->GetLODForDistance(testDistance1);
    RC_ASSERT(selectedMesh1 == mesh1);
    
    // Test: distance beyond all thresholds should select lowest quality LOD
    auto testDistance2 = distance1 * 2.0f;
    auto selectedMesh2 = group->GetLODForDistance(testDistance2);
    RC_ASSERT(selectedMesh2 == mesh1);
    
    renderer->DestroyMesh(mesh0);
    renderer->DestroyMesh(mesh1);
    lodSystem->DestroyLODGroup(groupId);
    renderer->Shutdown();
}

// Property Test: LOD Bias Effect
RC_GTEST_PROP(LODSystemPropertyTest, LODBiasAffectsSelection, ()) {
    /*
     * Feature: pywrkgame-library, Property 10: LOD Optimization
     * 
     * This test verifies that:
     * 1. LOD bias affects quality selection
     * 2. Higher bias values favor higher quality LODs
     * 3. Lower bias values favor lower quality LODs
     */
    
    auto renderer = std::make_unique<RenderingEngine>();
    RC_ASSERT(renderer->Initialize());
    RC_ASSERT(renderer->SetupLODSystem());
    
    auto* lodSystem = renderer->GetLODSystem();
    RC_ASSERT(lodSystem != nullptr);
    
    // Generate random bias value
    auto bias = *rc::gen::inRange(0.1f, 5.0f);
    
    lodSystem->SetLODBias(bias);
    RC_ASSERT(std::abs(lodSystem->GetLODBias() - bias) < 0.0001f);
    
    renderer->Shutdown();
}

// Property Test: Multiple LOD Groups Independence
RC_GTEST_PROP(LODSystemPropertyTest, MultipleGroupsAreIndependent, ()) {
    /*
     * Feature: pywrkgame-library, Property 10: LOD Optimization
     * 
     * This test verifies that:
     * 1. Multiple LOD groups can exist simultaneously
     * 2. Each group maintains its own LOD levels
     * 3. Modifying one group doesn't affect others
     */
    
    auto renderer = std::make_unique<RenderingEngine>();
    RC_ASSERT(renderer->Initialize());
    RC_ASSERT(renderer->SetupLODSystem());
    
    auto* lodSystem = renderer->GetLODSystem();
    RC_ASSERT(lodSystem != nullptr);
    
    // Create two groups
    uint32_t group1 = lodSystem->CreateLODGroup();
    uint32_t group2 = lodSystem->CreateLODGroup();
    
    RC_ASSERT(group1 != 0);
    RC_ASSERT(group2 != 0);
    RC_ASSERT(group1 != group2);
    
    auto* g1 = lodSystem->GetLODGroup(group1);
    auto* g2 = lodSystem->GetLODGroup(group2);
    
    RC_ASSERT(g1 != nullptr);
    RC_ASSERT(g2 != nullptr);
    
    // Create dummy mesh
    MeshData meshData;
    meshData.vertices = {0.0f};
    meshData.indices = {0};
    meshData.vertexCount = 1;
    meshData.indexCount = 1;
    
    auto mesh = renderer->CreateMesh(meshData);
    RC_ASSERT(mesh.IsValid());
    
    // Add LOD level to group 1
    LODLevel level;
    level.mesh = mesh;
    level.distance = 10.0f;
    level.triangleCount = 1000;
    
    g1->AddLODLevel(level);
    RC_ASSERT(g1->GetLODLevelCount() == 1);
    RC_ASSERT(g2->GetLODLevelCount() == 0);
    
    // Add LOD level to group 2
    g2->AddLODLevel(level);
    RC_ASSERT(g1->GetLODLevelCount() == 1);
    RC_ASSERT(g2->GetLODLevelCount() == 1);
    
    // Clear group 1
    g1->ClearLODLevels();
    RC_ASSERT(g1->GetLODLevelCount() == 0);
    RC_ASSERT(g2->GetLODLevelCount() == 1);
    
    renderer->DestroyMesh(mesh);
    lodSystem->DestroyLODGroup(group1);
    lodSystem->DestroyLODGroup(group2);
    renderer->Shutdown();
}
