/*
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Open Asset Import Library (assimp)
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*/
#include "UnitTestPCH.h"

#include "../../include/assimp/scene.h"
#include "PostProcessing/FindDegenerates.h"

#include <memory>

using namespace std;
using namespace Assimp;

class FindDegeneratesProcessTest : public ::testing::Test {
public:
    FindDegeneratesProcessTest() :
            Test(), mMesh(nullptr), mProcess(nullptr) {
        // empty
    }

protected:
    virtual void SetUp();
    virtual void TearDown();

protected:
    aiMesh *mMesh;
    FindDegeneratesProcess *mProcess;
};

void FindDegeneratesProcessTest::SetUp() {
    mMesh = new aiMesh();
    mProcess = new FindDegeneratesProcess();

    mMesh->mNumFaces = 1000;
    mMesh->mFaces = new aiFace[1000];

    mMesh->mNumVertices = 5000 * 2;
    mMesh->mVertices = new aiVector3D[5000 * 2];

    for (unsigned int i = 0; i < 5000; ++i) {
        mMesh->mVertices[i] = mMesh->mVertices[i + 5000] = aiVector3D((float)i);
    }

    mMesh->mPrimitiveTypes = aiPrimitiveType_LINE | aiPrimitiveType_POINT |
                             aiPrimitiveType_POLYGON | aiPrimitiveType_TRIANGLE;

    unsigned int numOut = 0, numFaces = 0;
    for (unsigned int i = 0; i < 1000; ++i) {
        aiFace &f = mMesh->mFaces[i];
        f.mNumIndices = (i % 5) + 1; // between 1 and 5
        f.mIndices = new unsigned int[f.mNumIndices];
        bool had = false;
        for (unsigned int n = 0; n < f.mNumIndices; ++n) {
            // FIXME
#if 0
        // some duplicate indices
        if ( n && n == (i / 200)+1) {
            f.mIndices[n] = f.mIndices[n-1];
            had = true;
        }
        // and some duplicate vertices
#endif
            if (n && i % 2 && 0 == n % 2) {
                f.mIndices[n] = f.mIndices[n - 1] + 5000;
                had = true;
            } else {
                f.mIndices[n] = numOut++;
            }
        }
        if (!had)
            ++numFaces;
    }
    mMesh->mNumUVComponents[0] = numOut;
    mMesh->mNumUVComponents[1] = numFaces;
}

void FindDegeneratesProcessTest::TearDown() {
    delete mMesh;
    delete mProcess;
}

TEST_F(FindDegeneratesProcessTest, testDegeneratesDetection) {
    mProcess->EnableInstantRemoval(false);
    mProcess->ExecuteOnMesh(mMesh);

    unsigned int out = 0;
    for (unsigned int i = 0; i < 1000; ++i) {
        aiFace &f = mMesh->mFaces[i];
        out += f.mNumIndices;
    }

    EXPECT_EQ(1000U, mMesh->mNumFaces);
    EXPECT_EQ(10000U, mMesh->mNumVertices);
    EXPECT_EQ(out, mMesh->mNumUVComponents[0]);
    EXPECT_EQ(static_cast<unsigned int>(
                      aiPrimitiveType_LINE | aiPrimitiveType_POINT |
                      aiPrimitiveType_POLYGON | aiPrimitiveType_TRIANGLE),
            mMesh->mPrimitiveTypes);
}

TEST_F(FindDegeneratesProcessTest, testDegeneratesRemoval) {
    mProcess->EnableAreaCheck(false);
    mProcess->EnableInstantRemoval(true);
    mProcess->ExecuteOnMesh(mMesh);

    EXPECT_EQ(mMesh->mNumUVComponents[1], mMesh->mNumFaces);
}

TEST_F(FindDegeneratesProcessTest, testDegeneratesRemovalWithAreaCheck) {
    mProcess->EnableAreaCheck(true);
    mProcess->EnableInstantRemoval(true);
    mProcess->ExecuteOnMesh(mMesh);

    EXPECT_EQ(mMesh->mNumUVComponents[1] - 100, mMesh->mNumFaces);
}

namespace
{
    std::unique_ptr<aiMesh> getDegenerateMesh()
    {
        std::unique_ptr<aiMesh> mesh(new aiMesh);
        mesh->mNumVertices = 2;
        mesh->mVertices = new aiVector3D[2];
        mesh->mVertices[0] = aiVector3D{ 0.0f, 0.0f, 0.0f };
        mesh->mVertices[1] = aiVector3D{ 1.0f, 0.0f, 0.0f };
        mesh->mNumFaces = 1;
        mesh->mFaces = new aiFace[1];
        mesh->mFaces[0].mNumIndices = 3;
        mesh->mFaces[0].mIndices = new unsigned int[3];
        mesh->mFaces[0].mIndices[0] = 0;
        mesh->mFaces[0].mIndices[1] = 1;
        mesh->mFaces[0].mIndices[2] = 0;
        return mesh;
    }
}

TEST_F(FindDegeneratesProcessTest, meshRemoval) {
    mProcess->EnableAreaCheck(true);
    mProcess->EnableInstantRemoval(true);
    mProcess->ExecuteOnMesh(mMesh);

    std::unique_ptr<aiScene> scene(new aiScene);
    scene->mNumMeshes = 5;
    scene->mMeshes = new aiMesh*[5];

    /// Use the mesh which doesn't get completely stripped of faces from the main test.
    aiMesh* meshWhichSurvives = mMesh;
    mMesh = nullptr;

    scene->mMeshes[0] = getDegenerateMesh().release();
    scene->mMeshes[1] = getDegenerateMesh().release();
    scene->mMeshes[2] = meshWhichSurvives;
    scene->mMeshes[3] = getDegenerateMesh().release();
    scene->mMeshes[4] = getDegenerateMesh().release();

    scene->mRootNode = new aiNode;
    scene->mRootNode->mNumMeshes = 5;
    scene->mRootNode->mMeshes = new unsigned int[5];
    scene->mRootNode->mMeshes[0] = 0;
    scene->mRootNode->mMeshes[1] = 1;
    scene->mRootNode->mMeshes[2] = 2;
    scene->mRootNode->mMeshes[3] = 3;
    scene->mRootNode->mMeshes[4] = 4;

    mProcess->Execute(scene.get());    

    EXPECT_EQ(scene->mNumMeshes, 1);
    EXPECT_EQ(scene->mMeshes[0], meshWhichSurvives);
    EXPECT_EQ(scene->mRootNode->mNumMeshes, 1);
    EXPECT_EQ(scene->mRootNode->mMeshes[0], 0);    
}
