#include "World.h"
#include <vector>

const int VERTEX_SIZE = 6;

const float topFace[24] = {
    // x, y, z, nx, ny, nz
    -0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
     0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
     0.5f, 0.5f,  0.5f, 0.0f, 1.0f, 0.0f,
    -0.5f, 0.5f,  0.5f, 0.0f, 1.0f, 0.0f
};
const float bottomFace[24] = {
    -0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
     0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
     0.5f, -0.5f,  0.5f, 0.0f, -1.0f, 0.0f,
    -0.5f, -0.5f,  0.5f, 0.0f, -1.0f, 0.0f
};
const float rightFace[24] = {
     0.5f,  0.5f,  0.5f, 1.0f, 0.0f, 0.0f,
     0.5f,  0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
     0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
     0.5f, -0.5f,  0.5f, 1.0f, 0.0f, 0.0f
};
const float leftFace[24] = {
    -0.5f,  0.5f,  0.5f, -1.0f, 0.0f, 0.0f,
    -0.5f,  0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f,  0.5f, -1.0f, 0.0f, 0.0f
};
const float frontFace[24] = {
    -0.5f,  0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
     0.5f,  0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
     0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
    -0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f
};
const float backFace[24] = {
    -0.5f,  0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
     0.5f,  0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
     0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
    -0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f
};

void addFace(glm::ivec3 pos, const float *faceVertices, std::vector<float> &vbo, std::vector<unsigned int> &ebo) {
    unsigned int vIndex = vbo.size() / VERTEX_SIZE;
    for (int i = 0; i < 4; i++) {
        const float* v = &faceVertices[i * VERTEX_SIZE];
        vbo.push_back(v[0] + pos.x);
        vbo.push_back(v[1] + pos.y);
        vbo.push_back(v[2] + pos.z);
        vbo.push_back(v[3]);
        vbo.push_back(v[4]);
        vbo.push_back(v[5]);
    }
    ebo.push_back(vIndex + 0);
    ebo.push_back(vIndex + 1);
    ebo.push_back(vIndex + 2);
    ebo.push_back(vIndex + 0);
    ebo.push_back(vIndex + 2);
    ebo.push_back(vIndex + 3);
}

World::World() {
    m_mesh.init();
}

Mesh& World::getMesh() {
    return m_mesh;
}

void World::generateMesh() {
    std::vector<float> vboData;
    std::vector<unsigned int> eboData;

    for (const glm::ivec3 pos : voxels) {
        if (voxels.count(pos + glm::ivec3(0, 1, 0)) == 0) {
            addFace(pos, topFace, vboData, eboData);
        }
        if (voxels.count(pos + glm::ivec3(0, -1, 0)) == 0) {
            addFace(pos, bottomFace, vboData, eboData);
        }
        if (voxels.count(pos + glm::ivec3(1, 0, 0)) == 0) {
            addFace(pos, rightFace, vboData, eboData);
        }
        if (voxels.count(pos + glm::ivec3(-1, 0, 0)) == 0) {
            addFace(pos, leftFace, vboData, eboData);
        }
        if (voxels.count(pos + glm::ivec3(0, 0, 1)) == 0) {
            addFace(pos, frontFace, vboData, eboData);
        }
        if (voxels.count(pos + glm::ivec3(0, 0, -1)) == 0) {
            addFace(pos, backFace, vboData, eboData);
        }
    }

    // Now, upload this data to our mesh object
    m_mesh.uploadData(vboData, eboData);
}