#include "AROTBuilder.hpp"

namespace DataSpec
{
logvisor::Module Log("AROTBuilder");

#define AROT_MAX_LEVEL 6
#define COLLISION_MIN_NODE_TRIANGLES 16

static zeus::CAABox SplitAABB(const zeus::CAABox& aabb, int i)
{
    zeus::CAABox pos, neg;
    aabb.splitZ(neg, pos);
    if (i & 4)
    {
        zeus::CAABox(pos).splitY(neg, pos);
        if (i & 2)
        {
            zeus::CAABox(pos).splitX(neg, pos);
            if (i & 1)
                return pos;
            else
                return neg;
        }
        else
        {
            zeus::CAABox(neg).splitX(neg, pos);
            if (i & 1)
                return pos;
            else
                return neg;
        }
    }
    else
    {
        zeus::CAABox(neg).splitY(neg, pos);
        if (i & 2)
        {
            zeus::CAABox(pos).splitX(neg, pos);
            if (i & 1)
                return pos;
            else
                return neg;
        }
        else
        {
            zeus::CAABox(neg).splitX(neg, pos);
            if (i & 1)
                return pos;
            else
                return neg;
        }
    }
}

void AROTBuilder::Node::addChild(int level, int minChildren, const std::vector<zeus::CAABox>& triBoxes,
                                 const zeus::CAABox& curAABB, BspNodeType& typeOut)
{
    /* Gather intersecting faces */
    for (int i=0 ; i<triBoxes.size() ; ++i)
        if (triBoxes[i].intersects(curAABB))
            childIndices.insert(i);

    /* Return early if empty, triangle intersection below performance threshold, or at max level */
    if (childIndices.empty())
    {
        typeOut = BspNodeType::Invalid;
        return;
    }
    else if (childIndices.size() < minChildren || level == AROT_MAX_LEVEL)
    {
        typeOut = BspNodeType::Leaf;
        return;
    }

    /* Subdivide */
    typeOut = BspNodeType::Branch;
    childNodes.resize(8);
    for (int i=0 ; i<8 ; ++i)
    {
        BspNodeType chType;
        childNodes[i].addChild(level + 1, minChildren, triBoxes, SplitAABB(curAABB, i), chType);
        flags |= int(chType) << (i * 2);
    }

    /* Unsubdivide */
    compSubdivs = 0;
    if (childNodes[0].childIndices != childNodes[1].childIndices ||
        childNodes[4].childIndices != childNodes[5].childIndices ||
        childNodes[2].childIndices != childNodes[3].childIndices ||
        childNodes[6].childIndices != childNodes[7].childIndices)
        compSubdivs |= 0x4;
    if (childNodes[0].childIndices != childNodes[2].childIndices ||
        childNodes[1].childIndices != childNodes[3].childIndices ||
        childNodes[4].childIndices != childNodes[6].childIndices ||
        childNodes[5].childIndices != childNodes[7].childIndices)
        compSubdivs |= 0x2;
    if (childNodes[0].childIndices != childNodes[4].childIndices ||
        childNodes[1].childIndices != childNodes[5].childIndices ||
        childNodes[2].childIndices != childNodes[6].childIndices ||
        childNodes[3].childIndices != childNodes[7].childIndices)
        compSubdivs |= 0x1;

    if (!compSubdivs)
    {
        typeOut = BspNodeType::Leaf;
        childNodes = std::vector<Node>();
        flags = 0;
    }
}

size_t AROTBuilder::BitmapPool::addIndices(const std::set<int>& indices)
{
    for (size_t i=0 ; i<m_pool.size() ; ++i)
        if (m_pool[i] == indices)
            return i;
    m_pool.push_back(indices);
    return m_pool.size() - 1;
}

static const uint32_t AROTChildCounts[] = { 0, 2, 2, 4, 2, 4, 4, 8 };

void AROTBuilder::Node::nodeCount(size_t& sz, size_t& idxRefs, BitmapPool& bmpPool, size_t& curOff)
{
    sz += 1;
    poolIdx = bmpPool.addIndices(childIndices);
    if (poolIdx > 65535)
        Log.report(logvisor::Fatal, "AROT bitmap exceeds 16-bit node addressing; area too complex");

    uint32_t childCount = AROTChildCounts[compSubdivs];
    nodeOff = curOff;
    nodeSz = childCount * 2 + 4;
    curOff += nodeSz;
    if (childNodes.size())
    {
        for (int k=0 ; k < 1 + ((compSubdivs & 0x1) != 0) ; ++k)
        {
            for (int j=0 ; j < 1 + ((compSubdivs & 0x2) != 0) ; ++j)
            {
                for (int i=0 ; i < 1 + ((compSubdivs & 0x4) != 0) ; ++i)
                {
                    int idx = k*4 + j*2 + i;
                    childNodes[idx].nodeCount(sz, idxRefs, bmpPool, curOff);
                }
            }
        }
        idxRefs += childCount;
    }
}

void AROTBuilder::Node::writeIndirectionTable(athena::io::MemoryWriter& w)
{
    w.writeUint32Big(nodeOff);
    if (childNodes.size())
    {
        for (int k=0 ; k < 1 + ((compSubdivs & 0x1) != 0) ; ++k)
        {
            for (int j=0 ; j < 1 + ((compSubdivs & 0x2) != 0) ; ++j)
            {
                for (int i=0 ; i < 1 + ((compSubdivs & 0x4) != 0) ; ++i)
                {
                    int idx = k*4 + j*2 + i;
                    childNodes[idx].writeIndirectionTable(w);
                }
            }
        }
    }
}

void AROTBuilder::Node::writeNodes(athena::io::MemoryWriter& w, int nodeIdx)
{
    w.writeUint16Big(poolIdx);
    w.writeUint16Big(compSubdivs);

    if (childNodes.size())
    {
        int curIdx = nodeIdx + 1;
        if (curIdx > 65535)
            Log.report(logvisor::Fatal, "AROT node exceeds 16-bit node addressing; area too complex");

        int childIndices[8];

        for (int k=0 ; k < 1 + ((compSubdivs & 0x1) != 0) ; ++k)
        {
            for (int j=0 ; j < 1 + ((compSubdivs & 0x2) != 0) ; ++j)
            {
                for (int i=0 ; i < 1 + ((compSubdivs & 0x4) != 0) ; ++i)
                {
                    int idx = k*4 + j*2 + i;
                    w.writeUint16Big(curIdx);
                    childIndices[idx] = curIdx;
                    childNodes[idx].advanceIndex(curIdx);
                }
            }
        }

        for (int k=0 ; k < 1 + ((compSubdivs & 0x1) != 0) ; ++k)
        {
            for (int j=0 ; j < 1 + ((compSubdivs & 0x2) != 0) ; ++j)
            {
                for (int i=0 ; i < 1 + ((compSubdivs & 0x4) != 0) ; ++i)
                {
                    int idx = k*4 + j*2 + i;
                    childNodes[idx].writeNodes(w, childIndices[idx]);
                }
            }
        }
    }
}

void AROTBuilder::Node::advanceIndex(int& nodeIdx)
{
    ++nodeIdx;
    if (childNodes.size())
    {
        for (int k=0 ; k < 1 + ((compSubdivs & 0x1) != 0) ; ++k)
        {
            for (int j=0 ; j < 1 + ((compSubdivs & 0x2) != 0) ; ++j)
            {
                for (int i=0 ; i < 1 + ((compSubdivs & 0x4) != 0) ; ++i)
                {
                    int idx = k*4 + j*2 + i;
                    childNodes[idx].advanceIndex(nodeIdx);
                }
            }
        }
    }
}

void AROTBuilder::Node::colSize(size_t& totalSz)
{
    if (childIndices.size())
    {
        nodeOff = totalSz;
        if (childNodes.empty())
        {
            totalSz += 26 + childIndices.size() * 2;
        }
        else
        {
            totalSz += 36;
            for (int i=0 ; i<8 ; ++i)
                childNodes[i].colSize(totalSz);
        }
    }
}

void AROTBuilder::Node::writeColNodes(uint8_t*& ptr, const zeus::CAABox& curAABB)
{
    if (childIndices.size())
    {
        if (childNodes.empty())
        {
            float* aabbOut = reinterpret_cast<float*>(ptr);
            aabbOut[0] = hecl::SBig(curAABB.min[0]);
            aabbOut[1] = hecl::SBig(curAABB.min[1]);
            aabbOut[2] = hecl::SBig(curAABB.min[2]);
            aabbOut[3] = hecl::SBig(curAABB.max[0]);
            aabbOut[4] = hecl::SBig(curAABB.max[1]);
            aabbOut[5] = hecl::SBig(curAABB.max[2]);
            athena::io::MemoryWriter w(ptr + 24, INT32_MAX);
            w.writeUint16Big(childIndices.size());
            for (int idx : childIndices)
                w.writeUint16Big(idx);
            ptr += 26 + childIndices.size() * 2;
        }
        else
        {
            uint16_t* pflags = reinterpret_cast<uint16_t*>(ptr);
            uint32_t* offsets = reinterpret_cast<uint32_t*>(ptr + 4);
            memset(pflags, 0, sizeof(uint32_t) * 9);
            for (int i=0 ; i<8 ; ++i)
            {
                const Node& chNode = childNodes[i];
                BspNodeType type = BspNodeType((flags >> (i * 2)) & 0x3);
                if (type != BspNodeType::Invalid)
                    offsets[i] = hecl::SBig(uint32_t(chNode.nodeOff - nodeOff - 36));
            }

            *pflags = hecl::SBig(flags);
            ptr += 36;

            for (int i=0 ; i<8 ; ++i)
                childNodes[i].writeColNodes(ptr, SplitAABB(curAABB, i));
        }
    }
}

void AROTBuilder::build(std::vector<std::vector<uint8_t>>& secs, const zeus::CAABox& fullAabb,
                        const std::vector<zeus::CAABox>& meshAabbs, const std::vector<DNACMDL::Mesh>& meshes)
{
    /* Recursively split */
    BspNodeType rootType;
    rootNode.addChild(0, 1, meshAabbs, fullAabb, rootType);

    /* Calculate indexing metrics */
    size_t totalNodeCount = 0;
    size_t idxRefCount = 0;
    size_t curOff = 0;
    rootNode.nodeCount(totalNodeCount, idxRefCount, bmpPool, curOff);
    size_t bmpWordCount = ROUND_UP_32(meshes.size()) / 32;
    size_t arotSz = 64 + bmpWordCount * bmpPool.m_pool.size() * 4 + totalNodeCount * 8 + idxRefCount * 2;

    /* Write header */
    secs.emplace_back(arotSz, 0);
    athena::io::MemoryWriter w(secs.back().data(), secs.back().size());
    w.writeUint32Big('AROT');
    w.writeUint32Big(1);
    w.writeUint32Big(bmpPool.m_pool.size());
    w.writeUint32Big(meshes.size());
    w.writeUint32Big(totalNodeCount);
    w.writeVec3fBig(fullAabb.min);
    w.writeVec3fBig(fullAabb.max);
    w.seekAlign32();

    /* Write bitmap */
    std::vector<uint32_t> bmpWords;
    bmpWords.reserve(bmpWordCount);
    for (const std::set<int>& bmp : bmpPool.m_pool)
    {
        bmpWords.clear();
        bmpWords.resize(bmpWordCount);

        auto bmpIt = bmp.cbegin();
        if (bmpIt != bmp.cend())
        {
            int curIdx = 0;
            for (int w=0 ; w<bmpWordCount ; ++w)
            {
                for (int b=0 ; b<32 ; ++b)
                {
                    if (*bmpIt == curIdx)
                    {
                        bmpWords[w] |= 1 << b;
                        ++bmpIt;
                        if (bmpIt == bmp.cend())
                            break;
                    }
                    ++curIdx;
                }
                if (bmpIt == bmp.cend())
                    break;
            }
        }

        for (uint32_t word : bmpWords)
            w.writeUint32Big(word);
    }

    /* Write the rest */
    rootNode.writeIndirectionTable(w);
    rootNode.writeNodes(w, 0);
}

std::pair<std::unique_ptr<uint8_t[]>, uint32_t> AROTBuilder::buildCol(const ColMesh& mesh, BspNodeType& rootOut)
{
    /* Accumulate total AABB */
    zeus::CAABox fullAABB;
    for (const auto& vert : mesh.verts)
        fullAABB.accumulateBounds(zeus::CVector3f(vert));

    /* Predetermine triangle AABBs */
    std::vector<zeus::CAABox> triBoxes;
    triBoxes.reserve(mesh.trianges.size());
    for (const ColMesh::Triangle& tri : mesh.trianges)
    {
        triBoxes.emplace_back();
        zeus::CAABox& aabb = triBoxes.back();
        for (int e=0 ; e<3 ; ++e)
        {
            const ColMesh::Edge& edge = mesh.edges[tri.edges[e]];
            for (int v=0 ; v<2 ; ++v)
            {
                const auto& vert = mesh.verts[edge.verts[v]];
                aabb.accumulateBounds(zeus::CVector3f(vert));
            }
        }
    }

    /* Recursively split */
    rootNode.addChild(0, COLLISION_MIN_NODE_TRIANGLES, triBoxes, fullAABB, rootOut);

    /* Calculate offsets and write out */
    size_t totalSize = 0;
    rootNode.colSize(totalSize);
    std::unique_ptr<uint8_t[]> ret(new uint8_t[totalSize]);
    uint8_t* ptr = ret.get();
    rootNode.writeColNodes(ptr, fullAABB);

    return {std::move(ret), totalSize};
}

}