#include "o3d/mesh.hpp"
#include <vector>
#include <array>
#include <cstdint>
#include <cstddef>
#include <tuple>
#include "math/vector.hpp"
#include "vulkan_utils.hpp"

using namespace engine::o3d;

Mesh Mesh::plane(float width, float height) {
    const float w2 = width / 2,
                h2 = height / 2;
    return {
        {
            { -w2 / 2, 0.f, -h2 / 2 },
            { +w2 / 2, 0.f, -h2 / 2 },
            { +w2 / 2, 0.f, +h2 / 2 },
            { -w2 / 2, 0.f, +h2 / 2 },
        },
        {
            { 0.f, -1.f, 0.f },
            { 0.f, +1.f, 0.f },
        },
        {
            {{ {{ 0, 0 }}, {{ 1, 0 }}, {{ 2, 0 }} }},
            {{ {{ 2, 0 }}, {{ 3, 0 }}, {{ 0, 0 }} }},
            {{ {{ 0, 1 }}, {{ 3, 1 }}, {{ 2, 1 }} }},
            {{ {{ 2, 1 }}, {{ 1, 1 }}, {{ 0, 1 }} }},
        }
    };
}

std::tuple<std::vector<engine::vk::Vertex>, std::vector<uint16_t>> Mesh::linearize_indices() const & {
    std::vector<engine::vk::Vertex> linearized_vertices;
    std::vector<uint16_t> linearized_indices;

    size_t n = 0;
    for (const auto& triangle_indices : this->indices) {
        for (const auto& vertex_indices : triangle_indices) {
            linearized_vertices.emplace_back(this->vertices[vertex_indices[0]], this->normals[vertex_indices[1]]);
            linearized_indices.emplace_back(n++);
        }
    }

    // TODO: I'm not sure if passing vectors like that makes a copy or not, because they are passed
    // to a structured which is instantly returned. I think that copy-ellision catches that
    return std::tuple { linearized_vertices, linearized_indices };
}