#include "rendering/mesh.hpp"

namespace wowee {
namespace rendering {

Mesh::~Mesh() {
    destroy();
}

void Mesh::create(const std::vector<Vertex>& vertices, const std::vector<uint32_t>& indices) {
    indexCount = indices.size();

    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), vertices.data(), GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(uint32_t), indices.data(), GL_STATIC_DRAW);

    // Position
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, position));

    // Normal
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, normal));

    // TexCoord
    glEnableVertexAttribArray(2);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, texCoord));

    glBindVertexArray(0);
}

void Mesh::destroy() {
    if (VAO) glDeleteVertexArrays(1, &VAO);
    if (VBO) glDeleteBuffers(1, &VBO);
    if (EBO) glDeleteBuffers(1, &EBO);
    VAO = VBO = EBO = 0;
}

void Mesh::draw() const {
    if (VAO && indexCount > 0) {
        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_INT, 0);
        glBindVertexArray(0);
    }
}

} // namespace rendering
} // namespace wowee