#include "chunk.h"
#include "world.h"

Chunk::Chunk(int x, int y) : m_posX(x), m_posY(y) { 
    std::ostringstream pos; // Vérifie l'existence d'un fichier .chunk avec sa position.
    pos << CHUNK_PATH << x << '_' << y << ".chunk";
    std::ifstream input(pos.str(), std::fstream::binary);

    if (input.fail()) {
        Perlin perlin = Perlin(8, 45.f, 7.f, PERLIN_SEED);
        m_blocks.Reset(BTYPE_AIR);

        for (int ix = 0; ix < CHUNK_SIZE_X; ++ix) // Montagnes
            for (int iz = 0; iz < CHUNK_SIZE_Z; ++iz) {
                float xnoiz, ynoiz;
                xnoiz = (double)(ix + x * CHUNK_SIZE_X) / (double)INT16_MAX;
                ynoiz = (double)(iz + y * CHUNK_SIZE_Z) / (double)INT16_MAX;
                float height = (perlin.Get(xnoiz, ynoiz)) * 20.f + 5.f;
                for (int iy = 0; iy <= (int)height % CHUNK_SIZE_Y; ++iy)
                    SetBlock(ix, iy, iz, BTYPE_METAL, nullptr);
            }
        for (int ix = 0; ix < CHUNK_SIZE_X; ++ix) // Collines
            for (int iz = 0; iz < CHUNK_SIZE_Z; ++iz) {
                float xnoiz, ynoiz;
                xnoiz = (double)(ix + x * CHUNK_SIZE_X) / (double)INT16_MAX;
                ynoiz = (double)(iz + y * CHUNK_SIZE_Z) / (double)INT16_MAX;
                float height = perlin.Get(xnoiz, ynoiz) * 5.f + 24.f;
                for (int iy = 0; iy <= (int)height % CHUNK_SIZE_Y; ++iy) {
                    if (GetBlock(ix, iy, iz) == BTYPE_AIR)
                        SetBlock(ix, iy, iz, BTYPE_GRASS, nullptr);
                }
            }
        for (int ix = 0; ix < CHUNK_SIZE_X; ++ix) // "Lacs"
            for (int iz = 0; iz < CHUNK_SIZE_Z; ++iz) {
                for (int iy = 0; iy < 13; ++iy) {
                    if (GetBlock(ix, iy, iz) == BTYPE_AIR)
                        SetBlock(ix, iy, iz, BTYPE_ICE, nullptr);
                }
            }
        for (int ix = 0; ix < CHUNK_SIZE_X; ++ix) // "Arbres"
            for (int iz = 0; iz < CHUNK_SIZE_Z; ++iz) {
                float xnoiz, ynoiz;
                xnoiz = (double)(iz * CHUNK_SIZE_Y + x * CHUNK_SIZE_X) / (double)INT16_MAX;
                ynoiz = (double)(ix * CHUNK_SIZE_Y + y * CHUNK_SIZE_Z) / (double)INT16_MAX;
                bool tree = (int)(abs(perlin.Get(xnoiz, ynoiz)) * 17933.f) % CHUNK_SIZE_Y > 126 ? true : false;

                for (int iy = 0; iy < CHUNK_SIZE_Y - 10; ++iy)
                    if (GetBlock(ix, iy, iz) == BTYPE_AIR)
                        if (GetBlock(ix, iy - 1, iz) == BTYPE_GRASS)
                            if (tree) {
                                for (int i = 0; i < (int)(abs(perlin.Get(xnoiz, ynoiz))) % 3 + 1; ++i)
                                    SetBlock(ix, iy + i, iz, BTYPE_DIRT, nullptr);
                                break;
                            }
            }
    }
    else {
        input.seekg(0, std::ios_base::end);
        int size = input.tellg();
        input.seekg(0, std::ios_base::beg);

        char data[CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z];
        input.read(data, size);
        input.close();

        for (int ix = 0; ix < CHUNK_SIZE_X; ++ix)
            for (int iz = 0; iz < CHUNK_SIZE_Z; ++iz)
                for (int iy = 0; iy < CHUNK_SIZE_Y; ++iy)
                    m_blocks.Set(ix, iy, iz, data[ix + (iz * CHUNK_SIZE_X) + (iy * CHUNK_SIZE_Z * CHUNK_SIZE_X)]);
    }
}

Chunk::~Chunk() {
    if (m_isModified) {
        char data[CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z];

        for (int x = 0; x < CHUNK_SIZE_X; ++x)
            for (int z = 0; z < CHUNK_SIZE_Z; ++z)
                for (int y = 0; y < CHUNK_SIZE_Y; ++y)
                    data[x + (z * CHUNK_SIZE_X) + (y * CHUNK_SIZE_Z * CHUNK_SIZE_X)] = (char)GetBlock(x, y, z);

        std::ostringstream pos;
        pos << CHUNK_PATH << m_posX << '_' << m_posY << ".chunk";

        std::ofstream output(pos.str(), std::fstream::binary);
        output.write(data, sizeof(data));
        output.close();
    }
}

void Chunk::RemoveBlock(int x, int y, int z, World* world) {
    m_blocks.Set(x, y, z, BTYPE_AIR);
    CheckNeighbors(x, y, world);
    m_isDirty = true;
}

void Chunk::SetBlock(int x, int y, int z, BlockType type, World* world) {
    m_blocks.Set(x, y, z, type);
    if (world) CheckNeighbors(x, z, world); // Si nullptr, ne pas vérifier les chunks voisines.
    m_isDirty = true;
}

BlockType Chunk::GetBlock(int x, int y, int z) { return m_blocks.Get(x, y, z); }

void Chunk::CheckNeighbors(int x, int z, World* world) {
    int cx, cy;

    world->GetScope(cx, cy);

    if (x == 0 && m_posX - cx >= 0 &&
        world->ChunkAt((m_posX - cx - 1) * CHUNK_SIZE_X, 1, (m_posY - cy) * CHUNK_SIZE_Z))
        world->ChunkAt((m_posX - cx - 1) * CHUNK_SIZE_X, 1, (m_posY - cy) * CHUNK_SIZE_Z)->MakeDirty();
    else if (x == CHUNK_SIZE_X - 1 && m_posX - cx < WORLD_SIZE_X && 
        world->ChunkAt((m_posX - cx + 1) * CHUNK_SIZE_X, 1, (m_posY - cy) * CHUNK_SIZE_Z))
        world->ChunkAt((m_posX - cx + 1) * CHUNK_SIZE_X, 1, (m_posY - cy) * CHUNK_SIZE_Z)->MakeDirty();

    if (z == 0 && m_posY - cy >= 0 && 
        world->ChunkAt((m_posX - cx) * CHUNK_SIZE_X, 1, (m_posY - cy - 1) * CHUNK_SIZE_Z))
        world->ChunkAt((m_posX - cx) * CHUNK_SIZE_X, 1, (m_posY - cy - 1) * CHUNK_SIZE_Z)->MakeDirty();
    else if (z == CHUNK_SIZE_X - 1 && m_posY - cy < WORLD_SIZE_Y &&
        world->ChunkAt((m_posX - cx) * CHUNK_SIZE_X, 1, (m_posY - cy + 1) * CHUNK_SIZE_Z))
        world->ChunkAt((m_posX - cx) * CHUNK_SIZE_X, 1, (m_posY - cy + 1) * CHUNK_SIZE_Z)->MakeDirty();
}

void Chunk::GetPosition(int& x, int& y) const { x = m_posX; y = m_posY; }

void Chunk::FlushMeshToVBO() {
    m_vertexBuffer.SetMeshData(m_vd, m_vcount);
    m_vcount = 0;
    delete[] m_vd;
}

void Chunk::Update(BlockInfo* blockinfo[BTYPE_LAST], World* world) {
    float u, v, s;
    // Update mesh
    if (m_isDirty) {
        int maxVertexCount = (CHUNK_SIZE_X * CHUNK_SIZE_Y * CHUNK_SIZE_Z) * (6 * 4);
        m_vd = new VertexBuffer::VertexData[maxVertexCount];
        m_vcount = 0;
        for (int x = 0; x < CHUNK_SIZE_X; ++x) {
            for (int z = 0; z < CHUNK_SIZE_Z; ++z) {
                for (int y = 0; y < CHUNK_SIZE_Y; ++y) {
                    if (m_vcount > USHRT_MAX)
                        break;

                    BlockType bt = GetBlock(x, y, z);

                    if (bt != BTYPE_AIR) {
                        blockinfo[bt]->GetTexture(u, v, s);
                        AddBlockToMesh(m_vd, m_vcount, bt, x, y, z, u, v, s, world);
                    }
                }
            }
        }
        if (m_vcount > USHRT_MAX) {
            m_vcount = USHRT_MAX;
            std::cout << "[ Chunk :: Update ] Chunk data truncaned , too much vertices to have a 16 bit index " << std::endl;
        }
    }
    m_isDirty = false;
}

void Chunk::AddBlockToMesh(VertexBuffer::VertexData* vd, int& count, BlockType bt, 
                           int x, int y, int z, float u, float v, float s, World* world) {
    
    int cex, cey;

    world->GetScope(cex, cey);

    int cx = x + (m_posX - cex) * CHUNK_SIZE_X, cy = z + (m_posY - cey) * CHUNK_SIZE_Z;

    if (y == CHUNK_SIZE_Y - 1 || GetBlock(x, y + 1, z) == BTYPE_AIR) {                      //  y
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z, .8f, .8f, .8f, u, v);
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z + 1.f, .8f, .8f, .8f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z + 1.f, .8f, .8f, .8f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z, .8f, .8f, .8f, u + s, v);
    }

    if (y == 0 || GetBlock(x, y - 1, z) == BTYPE_AIR) {                                     // -y
        vd[count++] = VertexBuffer::VertexData(x, y, z + 1.f, .2f, .2f, .2f, u, v);
        vd[count++] = VertexBuffer::VertexData(x, y, z, .2f, .2f, .2f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z, .2f, .2f, .2f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z + 1.f, .2f, .2f, .2f, u + s, v);
    }

    if (world->BlockAt(cx + 1, y, cy) == BTYPE_AIR) {                      //  x
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z, .9f, .9f, .9f, u, v);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z, .9f, .9f, .9f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z + 1.f, .9f, .9f, .9f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z + 1.f, .9f, .9f, .9f, u + s, v);
    }

    if (world->BlockAt(cx - 1, y, cy) == BTYPE_AIR) {                                     // -x
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z + 1.f, .5f, .5f, .5f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z, .5f, .5f, .5f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x, y, z, .5f, .5f, .5f, u + s, v);
        vd[count++] = VertexBuffer::VertexData(x, y, z + 1.f, .5f, .5f, .5f, u, v);
    }

    if (world->BlockAt(cx, y, cy + 1) == BTYPE_AIR) {                      //  z
        vd[count++] = VertexBuffer::VertexData(x, y, z + 1.f, .4f, .4f, .4f, u, v);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z + 1.f, .4f, .4f, .4f, u + s, v);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z + 1.f, .4f, .4f, .4f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z + 1.f, .4f, .4f, .4f, u, v + s);
    }

    if (world->BlockAt(cx, y, cy - 1) == BTYPE_AIR) {                                     // -z
        vd[count++] = VertexBuffer::VertexData(x, y + 1.f, z, 1.f, 1.f, 1.f, u, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y + 1.f, z, 1.f, 1.f, 1.f, u + s, v + s);
        vd[count++] = VertexBuffer::VertexData(x + 1.f, y, z , 1.f, 1.f, 1.f, u + s, v);
        vd[count++] = VertexBuffer::VertexData(x, y, z , 1.f, 1.f, 1.f, u, v);
    }
}

void Chunk::Render() const { m_vertexBuffer.Render(); }

bool Chunk::IsDirty() const { return m_isDirty; }

void Chunk::MakeDirty() { m_isDirty = true; }

void Chunk::MakeModified() { m_isModified = true; }